amsoil synchromesh?

[blownrunner]

I have a 2002 GTS, all stock. The FSM reads to use 75w-85 gear oil in the transmission. The T-56 is a synchromesh transmission, so why doesn't the FSM state to use this type of fluid? I have a 91' ZR-1 Corvette, also with a manual, and synchromesh oil is recommended.

I want to change the transmission fluid using an Amsoil product like their sychromesh oil. I really like Amsoil products and want to change everything over to their products. Thanks.

 

[Steve-Indy]

Actually, the 2002 Viper Service Manual states on page 21-4 "Fill transmission with Mopar Synthetic Manual Trans Lubricant 75 W-85 (MS-9070). This is a rebranded Castrol product used to suppress neutral gear rattle. It is important to use a G L-4 product.

 

[MoparMap]

Yeah, my understanding is that it is Castrol Syntorq in a Mopar bottle. However, Castrol Syntorq is just as hard and expensive to come by as the Mopar stuff. Others have swapped in different fluids without any issue, but it's whatever you're willing to put up with. There's always a chance it could cause a problem, but it's not like the car is in warranty or anything at this point. The T56 has been put in all sorts of vehicles that I'm sure use all kinds of different fluids. Carbon blocking rings and high power are what most likely drives the fluid selection.

 

[blownrunner]

Thanks. I have read how some people one these forums use the severe gear oil, but this actually appears to be the right oil to use based on the gl-4 and ms-9070 requirement: https://www.amsoil.com/lit/databulletins/g2077.pdf It has gotten a little colder here in Florida in December, and now a few times is has been more difficult to shift back into first. During the hotter months this wasn't a problem, but I have noticed today. Just got my 2002 GTS a few months ago and I guess it must be time for a fluid change.

 

[MoparMap]

I know what you mean about tough shifting. I drive my car all the time unless there is snow on the roads, so it has seen temps down in the 20s and probably even 10s a few times. Shifting it when cold is like stirring syrup, but after a few minutes of driving it loosens up and shifts just like normal. Just have to let things warm up a bit. The earlier cars with Dexron certainly have a lighter shift feel.