2017-2019 GM 6.6L Duramax Transmission Fluid Thermal Bypass Valve

The part is made extremely nice. Fits perfect. Trans was running 190-195, now it runs 160-162. Highly recommend to prolong the life of the grenade known as the 6L80.

Works Great Trans Temp here in Phoenix During the day Usually Hover around 195-205 installed This Bypass Valve Now I’m Seeing around 160-170. Heading to South Dakota in 2 weeks Pulling a Trailer that Should give it a Good Test. Other wise it’s doing what it’s supposed to do and the Build quality is Great.

Bought at the end of April, installed at the beginning of May, and gave it a real good test towing around 2500 lb through the Treasure Valley and Southeast Oregon desert the second week of June '25. Sorry it's taking so long for me to write this review, I just wanted to give a thorough review of the performance. Temperatures were mid 80s to mid-90s ambient air temperature. Before I averaged 180 to 199° F. towing through the same area a year prior. This year I never saw anything over 175°. In fact, the transmission fluid actually cools down when not under a load such as going down grades or flat level highway. Before the fluid would get warm and stay warm without ever cooling down unless you shut the vehicle off. Lots of grades and hilly terrain going through this area. Absolutely impressed with the performance of this thermal bypass valve. No more worrying. Was fairly easy to install with only a little fluid loss. Glad I found PPE! Also, my decal sticker looks good on the back window! ;-)

I cannot possibly say enough good things about your product. I was told I needed to spend 7K rebuilding my transmission and gave your product a shot as a last ditched effort and it saved me. It took me less than five minutes to install and instantly got my temps below spec (for reference the day prior I hit 258). It now rarely exceeds 170 which makes me much more comfortable. I commute 200 miles a day so that's very important to me. I'm sure I'll have transmission issues at some point but your product saved me a ton of anguish and money for now. Thank you not only for making a quality product, but getting it shipped to me quickly. I would recommend your products to anyone without hesitation.

Chevys are know for their trannies blowing up. The OEM thermal bypass valve is inferior. I had this PPE bypass valve installed and my transmission fluid dropped from 180°F-190°F down to 140°F - 145°F instantly. Also live in NC where it’s 90°F with 90%+ humidity