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Transmission Rebuild 101: A Shop Manager's Perspective

Introduction: The View from Behind the Service Desk

Well...How many out there have ever had your transmission rebuilt ? Okay, thank you for the show of hands. All of you are dismissed! Just kidding.

This article will be geared to the first-time person in need of a rebuild ... or to all you people "pre-transmission" rebuild ... to help you gain some insight.

What qualifies me to write on this topic? Simple, I was a commision-paid transmission shop manager for four years, making a good living. Quite often I had to explain many particulars about the transmission to my customers. Even some men needed a little crash course in transmissions when it came to having the thing underneath them rebuilt.

That thing underneath you all the time, like most things that we don't see all the time, tends to be taken for granted. But, like all machines...with every bit of use it begins to slowly wear down, every time you accelerate. That's just the nature of everything on the planet. So, someday without warning, you will have transmission troubles. Those of you who like to keep your vehicles a long time have probably already factored into your plans that one day you will need a transmission rebuild.

Transmission rebuilds are not cheap. Let me justify why a rebuild is going to cost you, and we will go from there.

Transmissions are big and bulky. It takes a great deal of care and expertise to do the job right from beginning to end. Transmissions, even standard transmissions, have a great many moving parts that need to work perfectly together like a watch. You would not try to "short-cut" putting a watch back together and then expect it to work properly. That goes double for that heavy, complicated piece of machinery beneath the floorboard of your vehicle. You are really counting on it to do its job right every time.

Nice clean professional shop with plenty of new automobile repair lifts.

Nice clean professional shop with plenty of new automobile repair lifts.

What Might a Good Transmission Shop Look Like?

When you walk into the front door of your local transmission shop, I'd like you to be prepared and know what to expect.

Why do you need to know what a good shop looks like? Because you don't want to pull into some "fly-by-night" operation, or a "flat-rate" shop, or a bunch of amateurs, do you? I mean you might like the sound of the price they give you ... but what good does that do you if you find yourself back on the highway and stuck again after a month or two? Know what to start looking for as you enter the parking lot of the transmission shop: the first one that you have chosen.

Unlike a restaurant, a lot of cars in the parking lot doesn't mean it's a good place to eat or that they are always busy. That a transmission shop has many cars in the parking lot might just mean that they are slow, or incompetent. You don't want me!

The Makings of a Good Shop

Ok, I'm educating you already (from behind the service desk) on things that make up a good shop and how it should look. That way you can begin to recognize good shops. Ones who will work hard for you and do the job right. Not some "shady" company with one beat-up ol' lift inside a building that is barely standing...and a few cats (and mice) making homes out of the vehicles left to be fixed... someday! Or, an old dilapidated Place that sends out some "unskilled" worker with lift stands and a ratchet to crawl under your vehicle to pull the tranny out on his back.

Now some good folks who make a living by pulling and rebuilding transmissions in a place like that...mainly local "shade-tree" mechanics. Just make sure that if you use them for your transmission job, that they come highly recommended from experience from a very good friend or family member, and that the transmission that was built for them worked for them for a very long time after the job.

OK, moving on. Let me cover some other good things that make up a good shop. Things you should look for.

There should be several of both of these items at a good shop for a good shop to stay busy, making money and keeping everyone happy.

  • At least one or two brand new lifts (lifts wear out and eventually need replacing after repeated use over the years.) Transmissions are not easy to get to. To access them quickly and efficiently requires two specialized tools right off the bat: an automobile lift and a transmission jack, neither of them cheap.
  • Several transmission jacks
  • Some employees in the shop, some hustle and bustle.
  • Some ironed-starched uniforms—maybe oily—actually they should be oily somewhere on the shirts if they have actually been working on vehicles.
  • Cases and cases of huge standing tool boxes. Each employee is responsible for having their own tools—all kinds of tools.
  • Organized parts area
  • Clean floor with few spills
  • A sign of some kind to discourage you from just walking around the shop floor (which means they actually carry insurance!),
  • At least one guy studying or carefully assembling a transmission
  • A very big parts washer (looks and sounds like a dishwasher),
  • A large metal press-looking machine
  • Visible air hose connectors on the wall with rubber air hoses
  • Cars that have been rotated off the lifts for the most part (at least after several days; some cars are too much trouble to move once the bottom frame for the front end has been removed),
  • Large storage tanks for new oil
  • Large storage tank for used oil
  • A clean public office area. (Maybe even some nice reading material, clean chairs, and fresh coffee ... at least in the morning),

Other things to look for in the public office area:

  • Mats, including welcome mats
  • Pictures of their favorite rebuilds/customers
  • Better Business Bureau insignias, or maybe even an award or plaque from the Chamber of Commerce or Rotary Club
  • Transmission Rebuilders Trade Association emblems
  • Some kind of poster promoting the products they use (meaning they do enough business to have sales reps of transmission-related products calling on them)
  • Basic information near the service desk bragging about their shop
  • Description of the warranties they offer (because they offer a great warranty which can be compared with other leading shops in the area),
  • A manager who is attentive to the fact that you just entered the shop office area.

These are all the makings of a professional shop. Look for these things when comparing a "ratty" run shop and a reputable one, even though some of these are just common sense.

A local independent shop will not have the kind of money a franchise can have for fancy floors, landscaping outside, and an espresso automatic coffee maker...and that may be a good thing. Maybe, the independent shop just wants to work hard at impressing you with the kind of work they do ... and leave that kind of frilly stuff to the big franchises. Big Franchises who in turn will put all those frills back into your final bill. Oh...and did I mention big advertising expense? Someone has to pay for the TV commercials or full-page ad in the paper. Independents don't usually have that kind of budget, but then they don't have that kind of overhead either. And, their price should reflect it! One way or another. We all get what we pay for!

The Owner Is Key

If you go to a "ratty" run shop...expect that type of quality in their work. Expect it in their attitude. Their attitude will tell you a lot about the quality of their work. Their professionalism will tell you a lot about how they perceive themselves. How they come across as you walk through the door...tells you a lot about the owner.

The owner of the shop is the key to the whole operation. An owner brave enough to stand behind the work of his people, proud enough of what he or she does to warranty a very complex piece of machinery, And proud enough of his company that he is willing to spend a few extra dollars to look sharp, look professional. There are reasons for everything the owner does ... you should be able to notice it from the minute you enter the parking lot. That goes into the kind of people he has working for him. The kind of business he is seeking. And the kind of quality he projects, and so on—you get the point.

Hate to say it...But a Good Quality Transmission Rebuild is going to cost some good money. Bottom Line.

Hate to say it...But a Good Quality Transmission Rebuild is going to cost some good money. Bottom Line.

What Goes Into the Price of a Transmission Job?

Now, let's look at another thing an informed customer needs to know about rebuilding a transmission. Specifically: how do you determine whether you are getting a fair price? Why does this work cost so much?

Here are some quick notes on things that you might not have thought of.

1. Be Prepared to Be Without Your Vehicle for a While

1. Your vehicle just had a major breakdown. It cannot be fixed overnight. There is a great deal to do to produce a completely repaired transmission.

2. Not Everyone Can Rebuild a Transmission

Not just any mechanic can rebuild a transmission. A transmission is a completely different creature from the engine, altogether, although rebuilding trannies shares some skills with rebuilding differentials and 4WD transfer cases.) It is like any other profession. Does the butcher come out from behind the counter to bag your groceries? No, there is a person for each task. The builder, like the butcher, is highly skilled. He rebuilds, as his main job. He knows about your particular transmission and the updates to it. He may know how to pull a transmission out of a car, but what he really does is build transmissions. The expertise needed demands strict devotion to building one transmission at a time. Nothing less!

Bigger shops with high volumes have many builders. Smaller Independents have one! The builder is the backbone of the business, like a skilled surgeon is to an operation on a vital organ. Transmissions don't work when built by people that don't know what they are doing. Period.

3. Transmissions Have Changed a Lot!

Whatever plan you had for dealing with transmission problems in the long-ago past does not work on modern transmissions, unless you have the luck of a gambler. Transmissions have evolved several times per decade since the long-ago days of the past. It isn't the same transmission that used to be under the floorboard of that old truck. I can't tell you how many people drove up to our shop and were shocked because the transmission didn't stop slipping because they changed the transmission fluid. OK, I fixed an old '82 Mercury that way too...back in the day. But things are much, much more different now.

4. It Won't Be Cheap

Because of the skill required, the number of parts involved, the precision necessary to do the job right, and the technical knowledge and technical updates involved, you are going to have to pay what the job is worth. Unless you have a family member in the transmission rebuilding industry that owes you money and a very big favor...It should not be cheap! The price to make this job right automatically includes

  • a basic rebuild kit,
  • a rebuilt torque converter,
  • any "hard parts" needing replacement,
  • the cost of parts getting to the shop,
  • and the hours of labor needed to
  1. pull the trans,
  2. put it back together accurately with quality parts,
  3. update it (the majority of the updates are done to the valve body...a highly intricate part of the tranny)
  4. reinstall it correctly,
  5. top it off with 14 quarts transmission fluid,
  6. road-test it,
  7. and adjust it if needed.

Those are the basic essentials of a rebuild, the bare minimum.

The shop needs to warranty the work for a minimum of 30 days (in most states). Our shop's average warranty, a few years back, was 2 years or 24,000 miles. Then the owner of that shop has to share a percent of the profit of that rebuilt transmission with his manager, and pay all the workers, the utilities, the upkeep, the misc. shop fees, towels, paper mats, carpet spot remover ... You get where I am going with this? It is going to take a reasonable amount of $$$ to do the job at the bare minimum.

Maybe, you don't want to think about all that included in the price. Maybe, you just want to fix the transmission for dirt cheap and get the vehicle down the road? Maybe you just want to resolve this current problem the quickest, and cheapest way possible? But now, which corner, out of the things above, are you willing to cut to get the result you desire?

If you want to go on in life with that particular automobile, with a completely rebuilt transmission, get this work started at a good shop that stands behind their warranty ... and feel good about making a wise choice. If you are not willing to do it at the price that a good shop gave you, and you decide to go with a shop with a ridiculous "low-ball' price, or replace your broken transmission with a used unit, then, expect the results of having a few corners cut! Again: "You get what you pay for!"

5. Beware the Low-Ball Price

How do I warn you to be aware of companies or individuals that would take advantage of you during this stressful event of trying to get your vehicle working again? By stating: "Beware the "low-ball" price." The guy down the road that has four cars permanently stuck to the pavement out in his parking lot, and offers to fix your transmission at a great low price, is not your friend. How did he give you a price over the phone when he doesn't even know what's wrong? What were the exact words he used when he gave you that price? Did he say "should be" that amount to rebuild? Maybe he even possibly outright said that the price could go up. So, at least he's honest when he said the "low-ball" could go up. The final price he ends up giving you may be the highest price around.

Honest shops will tell you that they have no idea what is wrong with your car before they see it., and won't know what is wrong with your transmission before they open it up! Get the picture? If you are given a "low-ball" amount for a job of this nature on a modern vehicle and the price is ridiculously low, Somewhere, somehow, there is a "short-cut" to get to the final outcome as compared to getting to a quality rebuild.

You may be the best shopper around...but your skills have to change for this job. Here the key is to compare apples to apples, oranges to oranges, and the quality of the shop matched up against the quality of the shop. Let quality shops determine the outcome of your vehicle...that's all I'm saying!

The most common view of your vehicle from a transmission shop's perspective.

The most common view of your vehicle from a transmission shop's perspective.

Transmission Terms, Part 1: Transmission Shop People

Like any profession, transmission rebuilding has its own jargon that describes what is happening. The people in the shop use their own lingo to each other.

In this first part section are some terms for people—owners, workers and customers.

By the way, in our business, a "trans" is just a transmission (you would not want to say the long version every time) and a "tranny" is a hot-rod magazine variant of that term.

"R & R Man"

This is the remove and re-install guy. Buy this guy a Coke. He is the one that puts actual hands on your vehicle. He gracefully removes your transmission (on a front-wheel drive or four-wheel drive vehicle that is no small task) and then "buttons it up."

"Swing Man"

An old term, but you should still hear it at big shops that have been around awhile. It refers to an R & R Man (who might even be an apprentice builder) who can build the old school trannies, such as an AOD ( 80's F-150 truck), 350 (70's GM Truck), and maybe everyone's favorite trans, from a front-wheel drive: The AXOD (Early 90's Ford Taurus). A lot of naturally good R&R guys become swing men ... just because they have been around so long and have picked it up over the years.


Well ... I just mentioned the best of the R&R Man ... let me mention the worst. There shouldn't be any butchers in the industry...that's the bottom line. A "butcher" is someone who butchers your transmission when putting it back in. They force the tranny back into place, don't know what the heck they are doing, end up with a bunch of extra parts, or end up screwing something up. Butchers don't cut it at any shop...for obvious reasons.


A repeat visit back from the same transmission. Never desired!


Same thing...the job goes on the Production Board as a C.B. "Come back".


This is a vehicle that is ready to return to its owner after being thoroughly road-tested.


UUGHH! A word associated with the scum of the industry. Anyone who tells you outright how much your particular transmission will cost without checking the condition of the "hard parts" is a "flat-rater.". They have no idea how many "hard parts" might be destroyed on the inside. So, when it becomes time to actually fix the transmission ... a variety of things can happen: They may have to give you a new price to cover the additional "hard parts" needing replacing. They may just install the "soft parts" with an overhaul kit and hope for the best. New seals and clutches are a good start to helping bring the transmission back up to specs, but your trans still needs every part that is inside it checked and brought back up to specs to be reliable again. If a "hard part" goes out later while you are driving around, because it was not replaced, because the shop you visited just gave you one "flat rate" price to technically only have an overhaul kit installed in it, guess what may need to be rebuilt again...only the near future?

Also, "flat-raters" have been known to spray down the outside casing of a transmission with a Varsol gun (Varsol is a solvent used for heavy-duty cleaning of intricate parts), and paint the outside of it, without the transmission ever being pulled!

About the only thing you may get out of them is a 30-day warranty on your transmission ("as is"... even though you didn't know better). But, seeing how they operate business...I imagine that 30-day warranty on your transmission is not going to be very helpful.


A short-cutters is a shop that cuts corners on a rebuild to keep the price low on a transmission. This can happen, for sure, if you get a quote from one shop and then another shop joins in on the hunt. When you try to pit two shops against each are probably the one who will lose! If a shop is honest, they know they can't tell if they do it for under the price the other shop gave without looking at the transmission. Again, one of the reasons for dealing with good shops!

If the shop you are at is trying to jack with you on a ridiculous price, research it, protest, negotiate, and take your complaint right to the owner. A good shop will be able to go toe-to-toe with you on price justification; they will be able to validate the price for work needed to be performed, and will care that this thing is costing you an arm and a leg. A bad shop could care less, or it won't be able to stand up to the scrutiny. Aren't good shops great!?

You Are a "Lead"

Whether you know it or not, or choose to be naive about it, you became a "lead" when you made your first call. Your transmission is a big sale to the shop. They will treat it as sales from the moment you make the first call. They are a business.

What y'all both do from here on out is completely up to how good of a business they are, and how well you can rely on them. If they have been around for any time at all, they didn't stay in business by not taking care of the customer. Just know that the bottom line for you—no matter what is said to get you in the front door—is that you have a rebuilt transmission that is reliable once again, and at a fair price. This is where you need to put your focus while talking to the shop that deserves your business!

You Are Also a Number

The minute your vehicle rolled into the lot...It became referred to by its Transmission name. If you vist the shop and check on their progress, and you hear them shouting A4LD or 4L60E or AX4LN, they may be talking about your and your vehicle and you would never know it. Or perhaps, you might have a fantastic shop manager like myself, who informed you of the model of your Trans and what problems it is prone to have, and of course, what updates we are doing and suggesting to help correct the problem.

Transmission Lingo Part 2: Types of Service

Fluid Change

Back a few years ago the interval for a fluid change was 25,000 miles, to keep everything in working order and keep the transmission at peak operation. After 100,000 miles it is better to use more caution on a fluid change. The main reason for that, is that transmission fluids have a detergent in them. When you combine that with the high pressure that transmission fluid operates at inside the unit, you may end up loosening a particle of something somewhere that can now travel through the valve body, if not caught by the transmission filter first. Something to think about. It is a fine balance though. With every rotation of the pump inside the transmission and use throughout the unit, the viscosity of the trans fluid begins to diminish through age and use.

Bench Job

When someone who works on cars and trucks all the time wants a transmission job done, they "pull it" themselves. They also install it themselves. That transmission goes straight to the builder's bench for Inspection. They won't get a full warranty until after they bring the transmission back to the shop upon re-installing it. That way the transmission shop can do a thorough inspection to make sure they put everything back correctly. It isn't as easy as sounds. There is a lot to keep track of on an installation, even on older vehicles that have easy underneath access to the trans.

Drop the Pan

Every honest shop should offer to inspect the transmission pan for free. Some front-wheel drive models from a few years ago do not have a pan that is accessible, and there might be other vehicles today that are like that. In the pan you might see the following things:.

  • a very large thick buildup of metal on the magnet to the pan;
  • dark, or dark brown tran. fluid is dark or dark brown (if it is burnt black it is burnt up inside):
  • "bronze" glitter (that is brass from the torque converter) in the tranny fluid
  • "silver" (aluminum; many planetary gear housings around the spline as well as other parts are aluminum) in the tranny fluid,
  • sludge pieces moving together like sand underwater (excess clutch material, or
  • metal chunks and small metal debris in the bottom of the pan

These are all signs of big transmission problems.

If, on the other hand, you have high mileage on your transmission and there is a small buildup of metal on the inside magnet in the pan, that is to be expected from normal wear. Start preparing for a transmission rebuild in your future. Don't feel like you have to sell the vehicle right away; that vehicle and transmission could have another 100,000 to 200,000 miles left in it. Whereas the next vehicle you get may not! Just monitor the amount of metal build-up with periodic checks to that transmission shop. An honest shop will want to work and build a relationship with a potential future customer. Especially, one who will come back to see them, and will talk about how honest that shop was, and was not trying to tell them they need a transmission rebuild quite yet...after a serious look at the pan! Aren't honest shops great?

Scan for Codes

Highly important in every evaluation of a trans condition are the electronics which are involved in how the engine operates including how the transmission operates. I can not explain all the intricacies of electronic sensors and solenoids throughout your vehicle, other than to tell you that your vehicle has them, including in the transmission. Unless it is an American vehicle of the very early '90s and before that. It would take another article to explain them and their different functions. I am no expert, but I did get very familiar with each one that was important to the proper operation of the motor and transmission. The rest is up to auto diagnostic experts and the process of scanning each vehicle for codes.

Transmission builders are very good with the important sensors and solenoids down the line that affect the operation of the transmission. It comes with experience. One benefit of scanning your vehicle for codes is that you can discover a bad solenoid inside the transmission right away, if it sends out a code. Most transmission centers will do this free for you as a service to the customer. They do this because it is a fairly quick way to get a picture of what problems your vehicle actually has. It may not be a trans problem at all, even if it feels like it to you, the customer. The scan helps get the ball rolling for the shop to see what the next step is.


Remove, disassemble, and inspect. Every shop has a term for this; this was ours. It means the internal inspection of your problematic transmission. The shop pulls your transmission and goes through it to find out which parts are salvageable and which are not. No one has any idea how much it will cost to repair your transmission accurately until this step happens. It is a Catch-22 of sorts, because you will have to pay some money to have this step done. It is a great deal of work. The transmission builder will:

  • examine each part,
  • measure all tolerances,
  • check all components based on his knowledge and experience,
  • evaluate the condition of gears and bearings inside your planetary gears,
  • inspect drums and splines for wear,

and so on. You get the picture.

The RDI fee will be waived once you both come to an agreement of the work that needs to be done and the price. Hence, the Catch already have a disassembled transmission lying on their workbench. You feel you are at an extreme disadvantage. Oh, but researched this company and got a reliable referral from someone you trusted first, you checked with the Better Business Bureau, and you are happy with the warranty they offer, and the way they deal with the customer. Correct? So go with the repair there...even if it is a little bit more than you were expecting.

  • This is a company with a proven track record. Correct?
  • You get what you pay for. Correct?
  • You want a good reliable rebuilt transmission, Correct?
  • I know you would rather pay this amount to fix the tranny than go down the road and get screwed. Right?
  • Aren't you glad you spent all the time up front checking out the Transmission Shop you are at...before you proceeded with having them begin any work?

Here's a bonus tip for you to feel a little bit better about this whole transmission repair ordeal, "R. D. I.", that you are going through: A good honest Shop will take the time to show you each and every problem, bad part, and necessary improvement that needs to be made to your sophisticated transmission. And your trans will be lined up in an organized fashion on the workbench to demonstrate all the work needed and parts needing replacement. They will explain what it will take, in order for you to have a completely-updated and back-up-to-specification rebuilt transmission. They should be able to educate you on many of the questions you have in regards to your rebuild, and give you all the benefits of having that particular unit rebuilt with them. A "not-so-honest" shop would probably want to pass on this step of the sale for a rebuild...and move on to less involved customers.

More About Come-Back Service

Why might a vehicle come back? Many times it can be non-transmission problems, a series of problems that caused the transmission to go in the first place. If the vehicle wasn't running when it came in, the transmission center fixed the problem they were assigned to: the transmission. Now, it is time to evaluate the underlying reason the trans had enough problems to cease working or function intermittently.

Often the problem can be traced from electronic solenoids acting up. Or your vehicle computer may have problems, brakes have been known to stick which will wear the trans. down in a hurry, your vehicle may have overheated on a hot commute once, and you didn't even notice the gauge (or the temp gauge may have intermittent problems) ... there are many other reasons. I know I have seen all kinds of combination problems associated with transmission problems.

Blame the people who put the electronic solenoids under the hood to begin with...and added a new series of problems. Seriously ... I ain't joking! Many solenoids control the shifts and other functions to the tranny coming from the vehicle's computer. As well as ones that control the engine, the emissions, the ignition switch, and one that even can act up if your vehicle's gas cap (on some makes) isn't secured tight enough.

In any case...both you and the shop will work through it, because you went to a good shop in the first place. Right? One that will stand by their work, honor their warranty, and help you all the way through the process of getting your vehicle right.


A cut-out is a transmission unit that is taken out of a junk vehicle. A shop that can afford a lot of inventory will have a lot of these. The hard parts are all pulled and mic'd (measured) for specifications. The outside transmission cases become part of the inventory as well, or can be scrapped for recycling. Although, today there are so many variations in case models, where they were made, etc. that it makes it hard to match a Transmission case. It is rare that an entire transmission case needs replacing. But, heat and abuse can crack or warp a case. It is not indestructible.

Many people choose to go with a "cut-out" or used unit as an answer to their rebuild problems. If you ask me, you just bought someone else's part (and their problem?) and have to start over with whatever history that unit has. Good luck if you go that route, you must be a gambler.

Most all transmission shops know what they are doing! They are not in the business of gambling with used transmissions. But, I'm sure you could pay them to install it professionally. That way, at least you can make sure that the used unit was installed correctly. Then, after that, it will be your headache to deal with moving forward. Heck, a really good shop will appreciate the opportunity to assist you and demonstrate their abilities during your project. That way, you will know who to bring that used transmission back to when it needs rebuilding!

Button It Up

Refers to the re-installation of the transmission. Everything from CV axles to frame pieces has to be removed to get to the transmission (and those are the basics). The R&R man becomes your personal vehicle's best friend ... and puts every little thing back in place...just the way it was before the transmission was removed.

Transmission Lingo Part 3: Problems and Symptoms


An uneven vibration that can occur at intermittent intervals. This is one sign (and a huge one at that) of a problem with your Torque Converter.

Stall Speed

Each factory has a pre-set stall speed for each torque converter. This is when the torque converter kicks in at a set RPM off of the motor, which is one of the many jobs of a torque converter.


A transmission whose "hard parts" have come apart on the inside (or whose torque converter came apart).


If your trans is burnt, the clutches have fried, or the Transmission has overheated for one reason or another. Reminder: The same tremendous heat that your engine is susceptible to...your transmission is, as well!

Blown Seal

A leak can happen at the front or rear seal of the transmission. If you have metal debris floating around in the transmission (which could be a "tell-tale" sign of bigger problems going on inside the transmission), then the metal can slip through at the seal, wreck the seal, and result in a bad leak. Also, seals go bad as part of wear and tear, The front and rear seals are the ones usually facing the outdoor elements day after day.

The transmission front pump components sit right behind that front seal, so if the front seal is blown, then the front pump may be in bad shape as well. Sorry to inform, but if this happens then the minimum a good shop will have to do to repair the leak is replace the front seal, rebuild the front pump, and replace the torque converter to insure a good seal on that front seal, one which fits snug around the hub of the torque converter.

But, remember what I said about metal debris and it possibly being a "tell-tale" sign. You might want to have the whole transmission checked to prevent another very possible return leak. (A point to think about: Quickest way to fry some clutches inside and "hard parts" is to run that trans without fluid!) In fact, if there is any metal debris inside the transmission, a good shop would not tell you that you can get by for long by just replacing the front seal and/or rebuilding the front pump. Because they know that will not be the ultimate solution to the problem.

If you're a gambler, you could probably find someone to just slap in a new front seal, without the rest of the repairs I mentioned. Anybody who would do that simple of a job would be crazy to warranty the job though, and you would be crazy to expect it to last. Better have a tow truck phone number handy, and pray that when the transmission goes (from other problems behind that original leak), that it doesn't happen late at night.

Some causes for front seals to blow are manufacturer defects with the pump, metal debris (as stated), and heat. Hot transmission fluid has to go somewhere, and the front seal is one of the big indicators that your transmission got hotter then it was spec'd for. This can be a very common problem in regions like Texas where folks are sitting parked for long periods on baking cement freeways with no circulation under their vehicle, and with the AC running, and the motor already running hot (your tranny butts up right to the motor). Some vehicle models are very prone to this condition, and although I won't mention them, I would like to thank them for all the business they created back in the day. One good solution to this is an aftermarket transmission cooler that can cool at greater capacity than a stock one, or the ordinary one that flows through the radiator (if the radiator gets hot—guess what happens to the transmission fluid flowing through the radiator?)

The transmission rear seal is a much easier and affordable fix than the front one; it can also be a "tell-tale" sign of what is going on in the transmission. However, the seal in the rear does need to be replaced as a solution to a problem if you have a high-mileage rear-wheel-drive vehicle that spends a lot of time parked "nose-pointed-up" on an incline, or if you ever had a U-Joint go bad. These are two things that can cause a rear seal to go out faster than you might be expecting on the tranny. This also applies to axle seals on front wheel drives that have problems with CV axles. Have those axle seals replaced to avoid an additional labor charge, and tow charge fee, or trans rebuild expense later. There is a good chance that after replacing a bad CV axle, somewhere down the line, the trans. fluid could start leaking. For gosh sakes...Please check the trans. pan every time you have a leak from a seal (although, a good shop will do this automatically.)

Late Hit

This means the shift takes a slightly longer time than normal to happen, and then when it does, it hits harder than it should. This can come from many causes, but the most common are bad solenoids, bad trans or front-end lower frame mounts, and also sludge buildup in the valve body. The sludge buildup would be from too much clutch material and/or metal shavings off of your internal metal components ("hard parts" that are wearing out) inside the trans unit. If too much debris enters the valve body (and the filter does not trap it), it will create all kinds of problems. One of the real problems it creates is "late hits" from sticking valves.


Pretty much even a novice to transmission problems can pinpoint this in a troubleshoot. The tranny does not engage into the next gear, period. Or it spends a great amount of time doing that. The feeling under the floorboard or hood (front wheel drives) is that of something "slipping." The main cause for this problem: clutch wear.

A Good Shop taking time to go over things with the customer.

A Good Shop taking time to go over things with the customer.

Well ,Class, I hope you have enjoyed getting a little bit of the inside scoop during this course, Transmission Rebuild 101. I know I have really enjoyed sitting behind the service desk once again, if only for a brief time. I hope that everything I have entrusted to you has helped make you a better and more educated consumer--a consumer that only a good shop could stand up to! See how that works!? (Author Smiles...)

I hope I was able to give you a lot of "meat and potatoes" from a former transmission shop manager's perspective. Thank you for reading this entire article...thus far. I hope that my Texas conversational writing style helped to make this read an enjoyable one.

Happy everyone out there!

Happy everyone out there!

© 2011 Me, Steve Walters