Trans service

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.
See posts with no answers
tlmgcamp

tlmgcamp

Well-known member
Joined
Jul 16, 2016
Posts
834
My daughter is looking to keep her car well beyond the 125k miles that is on it now. I am thinking about a service on the automatic trans, which has never been touched. I am hearing that messing with it now might stir things that best not be stirred. It's a Toyota Corolla, not an RV but hoping I could ask the group for some opinions
 
Toyotas don't have filters in the transmission, just a screen. One of the guys at work had (may still, we both retired and I haven't kept up with him) a Toyota Privia. Last I saw of it he was approaching a half million miles on it (he used shoe polish to write the mileage, 480K or whatever, in the back window. He made a point of telling everyone that he dumped the fluid in the transmission pan and refilled it, EVERY oil change.

When I got my Pontiac Vibe (a restyled Toyota Matrix built by NUMMI) which is built on the Corolla platform, I started doing the same thing. Every 10K I changed the full synthetic Amsoil motor oil, and the transmission fluid (3 qts to refill it, don't mess with removing the pan after you do it the first time, just dump and fill). I'm at 322K on it now. Biggest issue is the pan only has about two turns of thread for the drain plug, and it finally stripped out on me, so I replaced the pan and plug with genuine Toyota parts. Requires a new crush seal EVERY plug removal and takes 13 lb/ft (156 lb/in) and NO MORE.

I highly advocate for frequent fluid changes in any transmission, especially for those used in motorhomes or tow vehicles. But yes, get a new pan gasket and crush washer, drop the pan and wipe it out and also wipe the magnets off (make sure you get them in the right places when done) and replace the pan. I cannot see that you will be stirring up anything if you clean the pan out, it will have a black scum inside it. Get a genuine Toyota gasket, they are much better than the aftermarket ones.

Charles
 
Two things owners seem to neglect, automatic transmission maintenance and scheduled brake fluid replacement.
Many vehicle makers recommend replacing brake fluid every 3-5 years.
 
MH and trucks should have their transmission fluid changed on a regular basis since they are subject to extreme operating conditions. Changing transmission fluid for the first time in a car with over 100K miles is not a good idea unless the fluid is dark, smells burnt, or it doesn't shift right. In an older transmission particles build up in the fluid. These increase the friction on the clutches and bands and keep it operating. Replacing it with new fluid can cause it to start slipping.

This is one of those situations where people believe the reason their transmission lasts 200+K miles was because they changed the fluid on a regular basis. But it very well could have lasted 200+k without changing the fluid.
 
Last edited:
Older transmissions slipped because they had worn clutches and bands. Bands can be adjusted (however the last bands I know of were in Mopar transmissions discontinued in 2007) New transmissions monitor the input and output speeds and time the shifts. As clutches wear you would expect more clearance to develop and slippage from the large amount of movement of the clutch piston to engage the clutch. However, those speed sensors and the electronics vary the flow and pressure so that a shift on a 300K transmission feels just like the shift on a new one, its wearing out, you just don't know it.

Remember, you are not changing all of the fluid, I only get 3 qts from the pan. Total capacity is about 7 quarts, you are changing less than half of it. (the torque converter is holding the majority of the rest of it)

Clean fluid means the bearings and hydraulic components of the transmission are NOT experiencing excess wear from junked up fluid. Seals in clutch pistons, bearings and bushings, hydraulic valving, are not experiencing excess wear, that is how the transmission lasts longer. Fresh fluid also replenishes the additives in the fluid that help maintain pliable seals, and act as "friction modifiers" to reduce overall wear.

I don't buy the reasoning that the particulate matter keeps the clutches from slipping. If that were the case, my 322K transmission with extremely clean synthetic ATF would be slipping from lack of those particles. For me, the argument is just an old wives tale that doesn't make sense.

Charles.
 
Last edited:
Have it flushed. Replacing the quart or two in the pan is a fraction of the fluid needed in the transmission and torque converter.
I have my vehicles flushed about every 25k miles.
 
I'm with CharlesinGA 100%. Yes, changing fluid on a neglected transmission can trigger a failure. But the writing was on the wall, it was damaged already and I seriously doubt that wounded transmission would work much longer with failed fluid. I am totally in the camp of change early and often. OEM change intervals are based on "typical" use and what the manufacturer considers a useful service life. These are the same people in the business of selling new cars. You can stretch change intervals and maybe get lucky, or be more proactive and ensure that lubrication or contaminants won't be the primary failure mode during your ownership. It is so much easier to change fluids than change engines and transmissions. I don't change my transmission fluid every oil change but I generally will at half the recommended interval. I've done it several times now in my pickup which has a manual gearbox. Most folks would never change manual fluid but I'll do it every 50K. Same for axle goop. These are simple and inexpensive preventative measures to take so why not take them.

Mark B.
Albuquerque, NM
 
CharlesinGA said:
Older transmissions slipped because they had worn clutches and bands. Bands can be adjusted (however the last bands I know of were in Mopar transmissions discontinued in 2007) New transmissions monitor the input and output speeds and time the shifts. As clutches wear you would expect more clearance to develop and slippage from the large amount of movement of the clutch piston to engage the clutch. However, those speed sensors and the electronics vary the flow and pressure so that a shift on a 300K transmission feels just like the shift on a new one, its wearing out, you just don't know it.

Remember, you are not changing all of the fluid, I only get 3 qts from the pan. Total capacity is about 7 quarts, you are changing less than half of it. (the torque converter is holding the majority of the rest of it)

Clean fluid means the bearings and hydraulic components of the transmission are NOT experiencing excess wear from junked up fluid. Seals in clutch pistons, bearings and bushings, hydraulic valving, are not experiencing excess wear, that is how the transmission lasts longer. Fresh fluid also replenishes the additives in the fluid that help maintain pliable seals, and act as "friction modifiers" to reduce overall wear.

I don't buy the reasoning that the particulate matter keeps the clutches from slipping. If that were the case, my 322K transmission with extremely clean synthetic ATF would be slipping from lack of those particles. For me, the argument is just an old wives tale that doesn't make sense.

Charles.
Click to expand...
I did not say to stop replacing the fluid. I said it was not recommended on cars (only) that already had 100k without changing the fluid. Maybe you've never had one apart but older vehicles were pretty efficient at monitoring the input and output speeds and adjusting the pressure to time the shifts. Without electronics.

My Durango has the ZF-8 speed transmission with "lifetime fluid" like many new cars/trucks. That is likely planned obsolescence but the owners manual says changing it would void the warranty. There is no dipstick anymore so you can't tell if it is low. But my SIL has over 220K on his 2014 Jeep with the same transmission. It's still working fine without changing the fluid or even being able to check the level.
 
In 2001 we bought a new Toyota RAV4 and put 97,000 miles on it before passing it along to one of our daughters. At 130,670 miles she gave it to our grandson, who put another 96,000 miles on it at last check. In all that time, the only transmission problem has been a broken shift cable. The transmission was flushed at ~100,000 miles and hasn't been touched since. Our current RAV4 has just 67,000 miles on it plus another ~30,000 miles in tow behind our motorhome, and has had no transmission issues so far.
 
Modern light-duty (car) transmissions are impressive. By look and even by fluid analysis, the fluid in a tranny with 100k-150k miles still seems new. I doubt that changing it, either partial or full-flush, is going to have much effect on life of the tranny as a whole. I'm inclined to go with the look & smell test - if the fluid is still clean & clear with no "burnt smell", I'd leave it alone. Of course if in doubt, change it.

With my heavy duty Allison 3000 motorhome transmission, I began annual fluid analysis at age 6. After a few tests, it became evident that the fluid analysis was basically telling me when it was time to replace the twin filters. After a filter change, the fluid test showed basically the same condition as as 2-3 years previous, i.e. the last time the filters were changed.
 
tlmgcamp said:
. I am thinking about a service on the automatic trans, which has never been touched.
Click to expand...
Then do not touch it, if not leaking and no obvious issues. It is common for an auto-trans to leak after a fluid change as the new fluid cleans out the junk that was holding in the fluid.

With auto trannies, either change the fluid often or not at all.

At 125K miles, just wait until it breaks and then decide what to do. A fluid change is unlike to make it last longer at this point.

-Don- Reno, NV
 
We usually average about 250-300 k miles on a vehicle without ever messing with the Tranny.
The only time I ever had an Automatic Tranny fail was on The Mrs' Oldsmobile, when a guy at a Gas station talked her into having the Tranny serviced because the Fluid looked "a bit discolored" . It lasted about a month after that.
 
You must log in or register to reply here.

Latest posts

Members online

Total: 1,114 (members: 21, guests: 1,093)

Forum statistics

Threads
131,995
Posts
1,388,814
Members
137,741
Latest member
bogwoods
Back
Top Bottom