Freaking out. May be nothing

After enjoying ya'lls threads and opinions for many years, I might have a problem. The truck has aged from 110k to 130k since I bought it in 2020. I have kept up with regular maintenance and before we moved I did the drain fill on the transmission. However, lately, I have noticed the transmission is shifting a little bit rougher than I remember previously. It did two 5k lbs. for 16 hours and did it like a champ, but I am concerned the transmission is going to start acting up here soon as the shifting has gotten barely noticeable. It smoothed out to nothing after the fluid exchange and it has gotten rougher since then. Am I freaking out about nothing or would this be concerned? I am looking to also upgrade a few parts on the truck as well and am trying to get ahead of any noticeable things wrong instead of investing money in upgrades. Thanks so much for your help!

 

Are you sure the fluid level is correct?

If it was me, I would probably drain and fill it again for safe measure and then ensure the fluid level is correct (OBD2 temp gauge, IR thermometer, or short out the OBD2 pins).

 

Tell us more.

Is the transmission clunking, jerking, grinding or shifting slow?

Which gear is it most commonly happening in and at what RPM?

Is the roughness in an upshift or downshift?

Any tire changes recently?

 

Was your truck level when you filled it? You could be a little low on fluid. Recheck and see if its a nice trickle not a dribble. You can also add a 1/2 quart extra as the pan can accommodate extra fluid. I always add 1/2 to 3/4 quart after the trickle check.
Good luck.

 

Not clunking or jerking. No tire changes.

i used a cheap drain pan to measure how much came out. It was 4 quarts overfull. So I drained it to a drizzle. The truck was level and the driveway was as good as it gets. I’ll pull the plug after this weekend

 

I imagine our motor oil pans would accommodate more oil too. I would not suggest overfilling either.

I personally would perform another drain and fill (as suggested) with the correct fluid, and using the correct leveling procedure. Then you'll KNOW it's done properly, without adding fluid all willy nilly.

 

I agree and only state that as I've been doing it for quite some time now. Sometimes it does alleviate some shifting issues. Although could also be from a fill that was off.

 

This.

To add, how often do your u-joints get grease? Driveline slack - including soft springs - can imitate transmission shifting issues. Before you do anything else, I’d grease the u joints (assuming you have zerk fittings on thr joints; I don’t remember what year they stopped installing them but maybe 2018?) and drive around the block. My transmission always ‘shifted smoother’ after I grease the zerks.

If your springs are worn and tired, they can have a little bit of wrap between shifts that will feel like rough transmission operation. Throw some weight in the bed and take it around the block. See if it changes anything.

5k lbs for 16 hrs isn’t a big deal unless you were running with the converter unlocked the whole time and smoked the fluid from excessive heat. I’ve prolly done that much towing this month alone and the transmission is still happy. Last month was almost that much at max trailering weight.

Still, I would take the advice of doing another drain and fill. It won’t hurt anything, and it will give you an idea of how the fluid is holding up.

 

I hadn’t thought about the U-joints! I figured the towing wasn’t an issue, but drain and fill might not be a bad idea. Probably won’t do the usual 16 qts. The springs you referenced are the leaf springs?

 

When I didn’t grease my u joints it felt like I had a transmission issue. Greased them every oil change after I figured it out

 

Yes, the leaf springs. As they wear and flatten out a little, they don’t resist the axle torque as well and can wind up a little bit causing a small degree of axle wrap.

 

How are you getting 16qts on a drain and fill?

 

When people reference a transmission "Drain and Fill", it is draining ONLY THE PAN and will generally yield around 4 quarts removed and replaced. I believe this method is designed to avoid "shocking" the system with a complete replacement of ATF. I think a full fluid swap is probably a lot safer than a pressurized flush (at higher mileage), but still leaves room on the table for subsequent transmission problems.

So you probably don't need to do an actuall drain and fills but I would absolutely toss a quart in and perform the recommended leveling procedure to ensure you have the proper amount of ATF.

I also hear these Aisin transmissions are kinda picky about fluid types so I only use Toyota WS ATF in my tundra.

 

Did you check the level cold? Or hot? if you checked it cold, after refilling it, odds are you are really low on fluid. I did the level check cold without running it to the required temperature and had to refill it since there was nothing coming out of the check valve. Turned out all the fluid I dropped in, it spat out...