Rick's Free Auto Repair Advice

Transmission problems

How to evaluate and deal with transmission problems

Transmission problems usually cost big bucks. There’s no mechanical system in your car or truck with more moving parts than your automatic transmission. They can fail completely, where you step on the gas and nothing happens, or they can fail partially, where it won’t shift properly or makes strange noises. Finding the root cause of the failure is complicated and usually involves removal, teardown and rebuild. Few transmission problems can be solved with a quick and cheap fix.

What are the most common transmission problems?

Well, we have a tie for first place. Lack of response and late or no shifting are the two most common transmission problems. Let’s take a look at what can cause those.

1)     Lack of response: You put the pedal to the metal and you hear the engine RPMs pick up but you’re going nowhere. This is never a good symptom and fixing it almost always includes a total rebuild or the installation of a used transmission. The root cause can be a bad pump

transmission problems

Displacement gear style transmission pump

that can’t produce enough pressure to lock the clutch packs, a failed torque converter, a sticking valve body that’s not directing pressure to the proper areas, or a leaking internal seal that prevents the transmission from building pressure. Replacing each of these parts requires the technician to remove the transmission from the vehicle and tear it apart on the workbench. You simply can’t access these components with the transmission still in the vehicle.

2)     Late or no shifting or slipping: If the transmission shifts into a gear but won’t shift beyond that point and the check engine light or service engine soon light is on, your transmission may be in “limp in” mode. Car makers prevent a transmission problemsdamaged transmission from going through the full range of shifts in order to prevent further damage. But the point here is that there’s a root problem that caused the computer to put the transmission into limp mode. What are the possibilities: If you’re lucky, it’s just a bad speed input or output sensor or a malfunctioning shift solenoid. transmisison problemsSpeed sensors and shift solenoids can often be replaced without removing the transmission. But the first step is always getting the trouble codes read before replacing any parts. Beyond sensors and solenoids, the other possible causes of late or no shifting or slipping are far more serious and usually require teardown and rebuild.

3)     Transmission whines, clunks or grinds: You’ve got trouble with a capital T, dude. This is going to be an expensive fix. Don’t even ask if a bottle of transmission fix with cure it; it’ll be a complete waste of money—money you’re going to need for a transmission rebuild.

4)     Leaking fluid: Transmissions can leak fluid from the pan gasket (cheap fix), a servo cover gasket (perhaps two hours labor plus an inexpensive seal), transmission cooling lines (a bit more expensive), axle shaft seals (more transmission pan leakexpensive yet, but still manageable) or the torque converter seal (the seal is cheap but you’re talking a full day’s labor to remove and reinstall the transmission).

5)     Burning smell: A burning smell is almost always a symptom of an overheating condition and that’s never a good sign. Internal overheating can be caused by low fluid levels, excessive clearances that allow metal to metal contact, radiator obstructions or radiator fan problems that prevent the radiator from properly cooling the transmission fluid. Radiator and radiator fan issues can usually be diagnosed and repair for around $500. But if there has been internal overheating, you’re looking at the tip of the iceberg—the internal damage will require a rebuild. However, if transmission fluid is leaking onto a hot exhaust pipe that can usually be repaired for a moderate price.

Where to get transmission problems diagnosed and repaired?

Independent neighborhood auto repair shop

I usually recommend using an independent neighborhood shop for most repairs. But in this case I hesitate. Here’s why: most neighborhood repair shops don’t deal with transmission problems on a regular basis and they usually don’t do their own rebuilding. Instead, they remove the transmission and send it to a local rebuilder. That way they keep you as a customer and earn their normal hourly rate for removal and re-installation. Is there a problem with that? Not really, except that most independent neighborhood shops just narrow the diagnosis down to the transmission and then recommend a complete rebuild. They’re not really transmission experts so they don’t continue their diagnosis to find the root cause. That approach works for 90% of all their customers. But sometimes the transmission problems are just a symptom of a software or computer problem. In those cases the shop might recommend a rebuild only to discover it didn’t fix the problem. At that point the shop is out a lot of money for the rebuilder who did his job and they’re out all the labor for removal and replacement. The shop will be looking to you to pay the bill because, after all, you did get a rebuilt transmission.

If you use an independent neighborhood shop for major transmission repair, get some kind of assurance up front that they’ll stand behind their diagnosis and offer a solid warranty on the rebuild.

Should you go to the dealer for transmission problems?

Like an independent shop, most dealers don’t specialize in transmission rebuilds. If your transmission is toast, the dealer will replace it with a factory rebuild. However, they are often better equipped to diagnose a software or computer problem, and for that reason, I think you should consider having your car diagnosed there before you choose another shop. Yes, you’ll pay for the diagnostic work, but you don’t have to have the actual rebuild work done at the dealer.

Should you got to a transmission repair shop?

Now we’re getting down to the nitty gritty. Here’s the bottom line with transmission shops. Most chain operated transmission shops are either company owned or franchises. They don’t perform do their own rebuilding. They remove the transmission and send it to the franchisor or get a replacement from the company warehouse. In my opinion (and it’s just my opinion) no matter what’s wrong with your car, when you take it to a chain operated transmission shop, they will sell you a rebuilt transmission—because that’s all they have to offer. In most cases, their technicians are just trained on removal and installation, not diagnosis. So, my advice is to avoid chain operated transmission shops.

How about independently owned transmission shops? Maybe. First, they must belong to and be in good standing with the American Transmission Rebuilders Association (ATRA). Second, they must do their own rebuilding, have the latest scan tools and access to factory software, and have good diagnosticians. There are quite a few really good independently owned transmission shops around. But they’re hard to find. They don’t advertise on TV, they don’t offer discount coupons (because they don’t have to) and they have good ratings with Yelp and the BBB.

Bottom line: Go to a reputable independently owned transmission shop or your local dealer for diagnosis and repair.

Should you install a rebuilt transmission instead of rebuilding yours?

This is a really tough call because it depends on what killed yours. If your transmission is known for failing in a predictable way, then the replacement transmission from the junk yard will also fail that same way and you’ll be back in the same boat. Rebuilders usually update the transmission will parts specifically designed to prevent the same type of failure. So I would choose a rebuilt from a reputable local rebuilder or a factory rebuilt transmission from a dealer before I’d choose one from a junkyard that has known failure issues.

But if your transmission failed due to a leak, abuse or neglect, then a junkyard transmission may be a good option; as long as the shop has confidence in the supplier. What you want to avoid is shopping around junkyards for the best price on a used transmission and then asking a local shop to install it. You don’t know the reputations of the local junkyard, so you’re buying a pig in a poke. Don’t expect the installing shop to stand behind it, because they didn’t make any money on it. And don’t expect the junkyard to pony up a refund with a smile. They will blame the failure on the installing shop. At best, they’ll offer you another transmission, but they won’t pay for the labor to remove and replace it a second time. If you’re going to install a junkyard transmission, let the local shop find it and put their reputation on the line.

At what point should you walk away from a major transmission repair?

Look, most transmission repairs are expensive—in the $1,500 to $3,000 dollar range. Nobody can remove, rebuild and reinstall a transmission for less and do a good job. Hack rebuilders can throw in a Chinese rebuild kit (cost around $100) and “rebuild” your transmission for $800, but that’s not really a rebuild. They’ll reuse bands, gears, solenoids, etc. and they’ll do the job in their garage between the hours of 9:00pm and 3:00am while drinking beer and eating chips. Transmission rebuilding requires patience and cleanliness because you’re dealing with very tight tolerances with no room for dirt and crud.

So back to the question; should you rebuild the transmission or get rid of the car? Here’s my take: no matter how good the body is, a high mileage vehicle has high mileage. That means the engine, electronics, wiring, suspension, sub-frame and steering components all have high mileage. As they say, you can put lipstick on a pig, but you still wouldn’t want to date her. The same applies to pouring big money into a high mileage vehicle. If you’ve got more than 150,000 miles on your vehicle, think twice about putting $3,000 into the transmission, especially if it failed because of abuse or neglect, because that means you’ve abused or neglected other important maintenance items.

©, 2016 Rick Muscoplat

 

 

Posted on by Rick Muscoplat

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