would o`reilys carry anything decent for a 1st gen? i talked to them and asked for their top of the line..its synthetic but i forgot the name. they dont have amsoil OR redline...

 

I will say this once..The BEST possible synthetic gear oil money can buy (that I have found) is NEO snthetic RHD..You can buy it from
www.bakerprecision.com

 

I've used the Amsoil 75W-90 for many years with good results in both transmissions and non limited-slip diffs.
I've noticed that transmissions in particular run quieter, and in the case of my RX4, Amsoil basically "cured" my scritchy 3rd-gear synchro.

 

Yup! I've been using their 75w/90 HD gear oil for a long time, never had one problem with a trans or diff. As a matter of fact, it's all mazdatrix uses in all of their race cars.