is it fine to use redline MTL on manual transmission and differential on 93 fd rx7?

 

It's accepted that mt90 is the standard... No experience with mtl but it's listed as a 75-80 so I guess it would be fine

 

The FSM specifies 75w-90 and in a warm climate 80w-90. (GL-4 or 5)
MTL doesn’t meet spec.

 

so redline MT-90 is fine for transmission and diff?

 

Yes.

 

thanks, appreciate it.

 

MT90 is fine for transmission.
Differential takes 75/90 gear oil. Different additive package.

 

The service manual has an interesting statement about the differential fluid.

Apparently, some of these cars didn't come with a limited slip. Or this is more likely an error.

If you want a GL-5 fluid in the Red line family for your diff., I used 57904 (75W90) GL-5.

 

I think that's leftover from the copy/paste from the FC shop manual. All FD's had the Torsen diff.

Idemitsu makes a good gear oil as well, that's worth checking out.

Dale

 

Adding to this, don't use gear oil that has LSD friction modifier in it. Redline offers both options. That doesn't play well with the Torsen's 'clutches'. Avoid the shockproof stuff too. That also gums up the works in the Torsen.