[tthebeast21]

Recently I replaced the catalytic converter, and my car feels very responsive compared to what it felt like before. However I still have a issue where the transmission seems to be slow at changing gears, and this happens mainly in 2nd and 3rd gear. It isn’t rough, sometimes it will slightly jerk a bit but you can’t really feel it. The RPMs will jump up slightly before it goes into the next gear. It doesn’t happen all the time and when it doesn’t happen it shifts smooth. I would say it happens after the car is warmed up at operating temps but it’s happened a few times right after starting up then it just doesn’t happen at all.

I am planning on changing transmission fluid tomorrow , don’t know if it’s good to do so since the car is at 121k miles and I don’t think it’s ever been changed. But I’m not sure what else I can do anyways. Just hoping my transmission isn’t beginning to fail.

 

[DrivenDaily]

Yes, absolutely drain and fill the trans fluid. GM does not support any kind of flush, either by an external machine or by using the transmission to pump it out while you pour in new fluid.

Draining gets only about 1/2 of the fluid, so you may want to schedule a 2nd drain on the next oil change.

Then schedule the next one about 25,ooo to 35,ooo miles later.

 

[tthebeast21]

Yes, absolutely drain and fill the trans fluid. GM does not support any kind of flush, either by an external machine or by using the transmission to pump it out while you pour in new fluid.

Draining gets only about 1/2 of the fluid, so you may want to schedule a 2nd drain on the next oil change.

Then schedule the next one about 25,ooo to 35,ooo miles later.

Thanks, thats exactly what I’m going to do, drain and fill. My next oil change is at 123k so probably won’t be very long until I would need to change it again. I’ll be doing all of that myself, but I’m hoping changing it will help the trans out and fix that issue

 

[campb292]

On mine it was an occasional cold start flare between 3-4. Only cold, never when warm. Fix was a combination of fluid changes via drain and fill, getting the fluid level right (it was off 3/4 quart) and having the adaptive fast learn run.

 

[tthebeast21]

On mine it was an occasional cold start flare between 3-4. Only cold, never when warm. Fix was a combination of fluid changes via drain and fill, getting the fluid level right (it was off 3/4 quart) and having the adaptive fast learn run.

I drained and filled the fluid today and it was off by a quart when I measured it and was pretty much black. Put new fluid in and now it shifts great. Hoping it will stay like that until the next oil change which is when I’ll change it again

 

[tthebeast21]

Well a day later and the shift flare is starting to come back though not as bad as it was originally. It’s doing it cold and warm but again not all the time. I am going to change the fluid as soon as possible again, but I’m not sure if it matters but I used O Reillys Dexron VI fluid instead of ACDelco, hopefully that didn’t mess with anything? I’m guessing it would be too late to use OEM fluid now

 

[DrivenDaily]

To the best of my understanding, so long as the fluid meets OE specs, then it should not have contributed to the issue.

 

[campb292]

Setting fluid level can be finicky. What method did you use?

 

[tthebeast21]

Setting fluid level can be finicky. What method did you use?

I followed the PDF guide that was in here somewhere, but I measured the fluid by pouring it back into the container. It was low to begin with when I drained it (4qts) But I had bought 6 quarts and I put 5 quarts in. I did that because I didn’t want to overfill it in case there was more already in there and I’d have to take the tire off to actually check it


@DrivenDaily the label on the back of the jug says it is GM licensed fluid

 

[tthebeast21]

So I disconnected the battery a few times and it seems to be clearing up now. I've driven maybe 50-100 miles since and so far it hasn't really came back yet under moderate/heavy acceleration. I'm going to try and wait til next oil change to drain the fluid again, but I wouldn't consider this completely solved yet since there are a few times I can tell it wanted to shift differently