Who has used a high viscosity transmission fluid in a LV application?

[Rat407]

Yes. I use amsoil in all our vehicles and stand by it. However, while they recommended it for the 10r80…. I can’t believe they did. It clearly altered the characteristics of the transmission with about a 50% swap, slowing the shift precision and altering its feel during partial lockup (I think that’s what I was feeling). I dumped it and replaced with valvoline ULV. This was all to chase a problem which resolved beautifully after later adding just 2oz of LG red. Sure it was driveable, but it wasn’t right, lost its precision. Now with ULV and the LG, it’s almost as precise and out-of-the-way as the Lexus. The engineers really did their homework on the prgramming of that trans - it’s really that good when it’s happy. I’m not sure what happened between fluid chemistry and presumably the valve body materials. Cost cutting? Didn’t test the materials? Changed an o-ring material somewhere without testing?

Not sure what the difference is since this transmission was a joint effort. But my 10sp in my 2019 Silverado is running just fine on AMSOIL's ATL fluid. Swapped it over at the dealership.

 

[meep]

I’ve ridden in the gm applications and it does feel to me like they have different shifting strategies. They both highlight different attitudes. The ford seems to target quick, fast shifts in a more sporting manner. The gm seems a little more patient and more refined. the patience in the shifting may give wiggle room whereas ford’s rapid transitions reveal the difference? Just my theory.

 

[tig1]

A couple of years ago I switched from Valvoline LV ATF to M1 LV HP ATF in my 2017 Fusion with the 6F35 trans. I did notice better up and down shifting. In fact it shifts very smooth both ways. I believe the M1 atf has a 5.9 cst.

 

[tig1]

Yes, I do. The WS 100C viscosity spec is 5.3 cSt, + 0.5 cSt, - 0.3 cSt, and may be composed of Group III, IV and V base oils and additives.

https://www.mobil.com/en-th/passenger-vehicle-lube/pds/ap-xx-mobil-atf-ws
https://totachi.com/wp-content/uploads/2017/09/TDS_ATF-WS-1.pdf

Almost identical to what? Visual appearance tells you nothing as only a comprehensive analysis will really tell you the condition of the fluid.

Undoubtedly, you have never taken the full chemistry curriculum and your insistence on throwing in Off-topics indicates these are more emotional, rather than knowledgeable responses.

You may be right about visual appearance of ATF, but pouring in pink atf and draining out black atf is unsettling to me in an auto trans. The MC atf I used for awhile always came out black, but since changing to M1 LV HP a couple of years ago it always comes out pink. At least I feel better about it. Thanks for your replies.