STL010 Cooler Flow Bypass Valve Kit Upgrade Compatible With Cadillac Chevy Transmission 2014-Up GM 6L80 6L90, 2016-Up 8L90 8L80 8L90E,Automatic Transmission Assemblies

I bought this for a 2017 Chevy silverado with a 6 speed transmission with 46,000 miles on the truck. Trans temps were around 190F. After the install of this kit the average temp is now 135-140F. This kit lowered the temp about 50 degrees. I have been working on cars for 30 years. I am not sure whose bright idea it was to put a thermostat on a transmission but they should be slapped. REALLY HARD. Morons. The stock thermostat is set to 194F. That is too hot. The cooler you can run a transmission the better. This kit fixed that issue. I HIGHLY recommend this kit. Great value compared to the cost of a new transmission.It also has a bonus. There is no need to wait for the thermostat to open to add fluid to the system.They even give it a special name. What IS a thermostat they call it a Transmission Thermal Bypass Valve. Kind of the way Doctors have special names for things. (Just so they can feel smart). Heart attack = Cardiac event. Blood clot in the leg = deep vein thrombosis. etc etcThe install "can" be a bear. I live in Buffalo NY so rust and corrosion are always issues. Remove the transmission line from the Bypass valve. Remove the block from the transmission. Now you need to remove the snap ring holding the piece into the block. Once that is done you need to remove the end piece from the valve. That is the hard part(for me anyway). Mine would not come out. I prayed it with PB Blaster and used a little heat. The block is aluminum so be careful with any heat. After trying to remove it there was nothing left of the little tip that sticks out. Nothing for pliers to grab onto. None of this worked. I Finally drilled a small whole in the end and put a drywall screw in it. Now I had something to grab onto again. After a few minutes of trying to pull the piece out it finally began to loosen up. It then came out. There is no need to worry about this piece as you will never use it again. The kit comes with a new one and comes with new O-rings.Remember to check your trans fluid level when finished. You will not loose alot but you will need a little.NOTE: 2 years after the purchase of this truck GM redesign this valve. The new one opens at 154F instead of 194F. To my knowledge there is no recall for this. If there was, I was never notified.There are tons of youtube videos to help you rebuild the valve using the kit.

So lemme tell ya..my 2019 silverado was leaning towards 180 on a basic crosstown journey..maybe 20 miles..Read up in these and bought one..I just returned from a 5 hr trip from ga...I never went over 130 degrees!! It was roughly 75/80 degrees out..this thing works!!Highly recommend!!

Installed in a 2018 GMC Sierra with 8 speed trans. Factory trans thermo was a 180 degree. This kit now allows trans fluid to run at 120 degrees and lower. Haven’t towed a trailer yet, but I’m sure it will keep trans fluid cooler by over 50 degrees or more. Kit is good quality but only negative was that no instructions were included with the kit. A simple diagram breakdown of pieces would have been nice.

Seems to work good so far for 30k miles keeps the trans at about 130-170

Good kit, easy to install. Lowers your operating temp 20 degree's lower, sometimes less. However, along with this kit you need to do a full system flush and drain because GM used crappy oil and they put the worst torque converters in these trucks. I have a 2021 Silverado with 41,000 miles and I already had TC shudder and funky shifting. As soon as I put this kit in and flushed the trans all those issues went away. I have 3 friends with transmission failure already. Shame on you GM. Fire your engineers! Just my thoughts.

I was reading about the 8L90 trans temp and saw future failure on it due to it over heating, drove for 30 min on the stock thermostat and jumped up to 160-190 F. I decided to order and install this part for peace of mind. Easy install fit as it should in the thermostat took about 15min to install and remove the oem part, came with 1 extra O ring, felt like great quality. It functioned as it should dropped my temperature to 130-140F on a 30 min drive. Happy with the results hope this review helps!

This valve did not lower my transmission temperature at all.

These are great and work well, there a simple install and then keeps your transmission running cooler! A must on the 6L80 GM!