[2016ghost]

Having the transmission temp sensor replaced in my car and the trans shop uses Castrol Transmax fluid and said that's all he uses in all transmissions by GM and other manufacturers, said saying only use Mobil1 blue label was just a money making thing between ExxonMobil and GM, and as long as you put in the same formulation recommended by GM it will be fine. Transmax is Low Viscosity and for high performance use according to what I've read. My car has had two flushes and that was done before the Mobil1 Blue Label came out, so I don`t know what fluid it actually has in it right now, and it has a slight shudder but not very often. Should I request or take some Mobil1 blue label with me so he has it or let him put the Castrol in it and keep my fingers crossed?

[Deacon Blues]

I mean I feel like if you're paying for it, you should get what you want...not saying the shop is wrong but if you want the official/correct fluid, it should be your call (or find another shop).

[NashZL1]

https://www.castrol.com/en_us/united...-transmax.html

They say it's a universal fluid that works in traditional automatics and CVTs. One size fits all? Interesting.

I'd personally stick with OEM recommended fluid.

[OB0001]

Originally Posted by 2016ghost

Having the transmission temp sensor replaced in my car and the trans shop uses Castrol Transmax fluid and said that's all he uses in all transmissions by GM and other manufacturers, said saying only use Mobil1 blue label was just a money making thing between ExxonMobil and GM, and as long as you put in the same formulation recommended by GM it will be fine. Transmax is Low Viscosity and for high performance use according to what I've read. My car has had two flushes and that was done before the Mobil1 Blue Label came out, so I don`t know what fluid it actually has in it right now, and it has a slight shudder but not very often. Should I request or take some Mobil1 blue label with me so he has it or let him put the Castrol in it and keep my fingers crossed?

Wrong.use only the blue label Mobile

[Spaceme1117]

Use the Mobil 1 Synthetic LV ATF HP that GM specifies. That is the correct fluid.