6L80 Trans pill flip maintenance question

mikeyk101 · October 30, 2021

My thoughts... The new updated thermal valve can be had for just over $50 online and new gasket, a couple bucks and shipping of around $15. It shouldn't take more than about 10-15 mins tops to swap out. The dealer will charge a diagnostic charge of most likely more than this to check plus the time to go to dealer, wait for diagnostic check, and then the swap out. I would have to allocate way more than 15 mins and that's assuming they could get to it right away. It just seems like this would be a great weekend project and would be done on my time. I know that if done under warranty the diagnostic charge wouldn't apply bit that's also assuming that the dealer agrees that the thermal valve needs to be changed. And if they don't agree, then I will have to eat the diagnostic charge and then have to go through the motions at another dealership that may or may not change out the valve. I am leaning towards just picking this up on my own so I won't have any questions like I might if my pill flip mod was to be discovered.

And I know many here who have done the pill flip mod say that there are no issues with doing it and then dealing with the colder temps in winter. I haven't experienced this yet as I did it earlier this year well after winter. But this could help give me piece of mind as the trans would probably warm up quicker in cooler temps but still have protection as it would no longer have to heat up to 190⁰ before the trans cooler came into play. It's seems like this is a no brainer. Granted it is more expensive than just doing the free pill flip mod, but would be considerably cheaper and less time than dealing with the dealer. I think I will be ordering this soon...

mikeyk101 · November 4, 2021

I ended up ordering from http://gmpartsgiant.com and their prices seemed reasonable. I got notification that it shipped from Milford, OH and should be delivered on Sat but not sure when I will be able to install it. Since I've been under there before for the pill flip, it should be pretty simple to do.

But when I took the "thermo valve" off the last time, I don't remember there being a gasket between the valve and the transmission. I did order the gasket but not sure if it requires any kind of sealant or if it goes on dry. Can anyone enlighten me on this?

Edited November 4, 2021 by mikeyk101

Grumpy Bear · November 4, 2021

2 hours ago, mikeyk101 said:

I ended up ordering from http://gmpartsgiant.com and their prices seemed reasonable. I got notification that it shipped from Milford, OH and should be delivered on Sat but not sure when I will be able to install it. Since I've been under there before for the pill flip, it should be pretty simple to do.

But when I took the "thermo valve" off the last time, I don't remember there being a gasket between the valve and the transmission. I did order the gasket but not sure if it requires any kind of sealant or if it goes on dry. Can anyone enlighten me on this?

Dry

bayouguy71 · November 4, 2021

Why the gasket on the new one and none with the old?

Does anyone know?

I have mine flipped but am also following this subject.

Grumpy Bear · November 4, 2021

7 hours ago, bayouguy71 said:

Why the gasket on the new one and none with the old?

Does anyone know?

I have mine flipped but am also following this subject.

Pretty sure the gasket is on all of them; may stick to the valve, may stick to the transmission.

mikeyk101 · November 5, 2021

9 hours ago, Grumpy Bear said:

Pretty sure the gasket is on all of them; may stick to the valve, may stick to the transmission.

I will have to look carefully when I swap out the valves. Like I mentioned, I didn't recall any gasket when doing pill flip but might have missed it and was stuck on trans like you say. Either way, I have a new gasket and will have to make sure that there is no old gasket left behind which would be a problem. Thanks!

11bravoZ71 · December 19, 2021

Not to thread Jack. But speaking of the new 158f thermostat since so far it’s only out for the 6l80…for those who might want to use a factory method of lowering the 8l90 temperature

I decided to buy one from the dealer about 2 weeks ago thinking I can use it in my 8l90 but the housing is different so I just opened it swapped the “pill” they are identical other then the 135F stamp And 180F stamp on the 8l90’s…. I simply reused my 8l90 thermostat housing and happy to report it works as intended I drove about 6 hours total today towing a light car on a trailer and the highest I saw was 165F in town. And highway was 145 ishh.

without towing after fully warmed up it’ll hover between 140 and 160

id you drive like a maniac it’ll go up to 169 at the max. And that’s trying. With 75 degree SoCal weather.

Will never go back 190+ temperatures on any GM trannys. That Heat kills them by 150k or less miles IMO and all the data I’ve read etc.

Edited December 19, 2021 by 11bravoZ71