[Rob S]

I bought a 2011 Enclave with 87k miles on it a few years back. Trans started shifting late and other minor annoyances. Had the dealer change the fluid for $100 and things improved. Since then I have the trans fluid every 30k miles (120k & 150k). My Enclave has 164k miles on it and trans shifts fairly well but intermittently shifts late.
Cannot emphasize the importance of changing the trans fluid on 1st generation models. 2nd generation also seems to benefit as well.
I did research and have been happy with the XADO trans fluid treatment (on Amazon). Magic Russian "cureall" oil does seem to make a difference with how my Enclave shifts. Less delay and a bit less slippage.
You should also consider adding a transmission cooler to supplement the factory one.
Cheers.

 

[Rob S]

Figured I'd update this. Did the drain and refill a few weeks ago. While doing it I noticed the front brakes were pretty bad so decided to do them at the same time. After the first re-fill took the E to get new pads/rotors and took the long way home. Drove it pretty hard to redline through the first couple gears to get it mixed up well and since I was still filthy and didn't feel like doing this job again in a week I decided to just do the 2nd drain and fill immediately. After about a week the occasional clunk I'd get on the very first cold shift from 2nd to 3rd is gone. Didn't really see any other differences but I also wasn't experiencing any other issues. Fluid was pretty brown on the first drain but didn't smell burnt or anything. 2nd drain had pretty good color so I'm confident what's in there now is mostly new fluid.

Thanks for the follow-up post. I have considered changing the fluid twice in a row like you did but the minor slippage issues always disappear after the 1st change.