2020 GMC SIERRA TRANSMISSION FLUID

Nasser Aldhaheri · May 18, 2023

Hello,

i have recently bought a 2020 GMC Sierra with 91,000 KM (56,544 Miles) on the dash, as per the manual, I should change my transmission fluid every 70,000 KM (43,495 Miles). Meaning I am ~13,000 Miles over the recommended transmission fluid change. I have checked the color of the transmission fluid and it’s dark red.

I am not facing any issues other than the gear clunk (feels like someone rear ended me) when downshifting during a full stop. (From third to second gear/second to first gear) can’t really tell and it happens 3/10 times during a stop, but have heard on the forum it’s a common problem and is fixed by a resetting (which I plan to do if I change my transmission fluid). Other than this issue the car shifts smoothly.

The question is, is it too long overdue to change the transmission fluid? Should I change it?

Thanks!

repairman54 · May 18, 2023

Change it. A little overdue is no problem.

If a transmission fails due to a fluid change it was going to blow anyway. Old mechanics wife stories.

Gangly · May 18, 2023

12 hours ago, Nasser Aldhaheri said:

Hello,

i have recently bought a 2020 GMC Sierra with 91,000 KM (56,544 Miles) on the dash, as per the manual, I should change my transmission fluid every 70,000 KM (43,495 Miles). Meaning I am ~13,000 Miles over the recommended transmission fluid change. I have checked the color of the transmission fluid and it’s dark red.

I am not facing any issues other than the gear clunk (feels like someone rear ended me) when downshifting during a full stop. (From third to second gear/second to first gear) can’t really tell and it happens 3/10 times during a stop, but have heard on the forum it’s a common problem and is fixed by a resetting (which I plan to do if I change my transmission fluid). Other than this issue the car shifts smoothly.

The question is, is it too long overdue to change the transmission fluid? Should I change it?

Thanks!

Change it if you can, but I wouldn't lose any sweat over it not being changed yet. I think the recommended interval is around 45K miles, but that's for SEVERE use.