Rear end oil.

[Miami Dolphins]

getting ready to swap center section on my 71-340 Demon, going from 3:91 to 3:23 sure grip. I have decided to use synthetic but not sure on the viscosity, 85W140 OR 75W90, the car is stock and I live Georgia. Any suggestions??? I will add a bottle of the sure grip additive.

Thank you.

 

[rrvolare]

Not synthetic for 742 case unit ... 80/90 with additive ...

 

[fishy68]

Not synthetic for 742 case unit ... 80/90 with additive ...

Why not? What does synthetic hurt in a 742? I've used it with no issues in a 742. Agree on the 80w90