8L90 Thermostat bypass

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

06 Taco

TYF Newbie
Joined
Nov 18, 2019
Posts
27
Reaction score
5
I have a 2015 Yukon Denali 6.2 with the 8L90. I am planning on ordering the Superior sure cool STL010 or the TransGo 6L80-CLR BYPASS thermostat mod and I'm curious if anyone has had any issues? I live in Florida and usually spend summer in Connecticut so I'm not concerned that the transmission won't run hot enough. I'm hoping that the transmission will run a lot cooler on the drive from FL to CT.
 

B-train

Full Access Member
Joined
Sep 12, 2022
Posts
2,421
Reaction score
4,224
I have the same transmission and was going to do the same. I bought a kit that advertised it did both the 6 and 8 speeds. I asked my friend (master GM tech of 35 years) about the longevity of the 8 speed with heat failure vs the 6 speed. He said they are really good transmissions once you get the correct fluid in them and aren't prone to the same failure.

Keep it serviced every 40k and leave it be. It uses a completely different fluid than the 6 speed as well. I never ended up putting it in and just left it as is. Currently at 170k.
 
Top