A couple of on-line houses (Bofi and Flyin Miata) are recommending 50./50 Redline MT90 and Redline Light Shockproof for 5 and 6-speed XMSNs.

I know Joe had a 6-speed fluid thread a couple of years ago, but I cannot find it, only Hustler's old thread(s).

Any thoughts on the above mix? Experiences with it.

DNMAKINSON

 

Apparently as far as wear protection is concerned, places that rebuild and open a lot of Miata transmissions seem to be liking Motul.

 

In for answers. Ive always used straight mt-90 and some mobil 75-90 in my run down 6 speed.
I get cold gear whine in 1/2 gears, less so with mt-90 and have considered the same mix on my next fluid change.

 

Forget about MT90, shockproof, etc. Just get Motul Gear 300 and be done with it.

 

Okay. Use same in Torsen Diff?

 

This is interesting. Any details about the reasons for that?

I put Motul Gear 300 in my 6 speed and Torsen last summer.

There was an immediate improvement in smooth shifting quality but it didn’t last long before getting notchy again, especially 1st - 2nd.

I more recently swapped to Castrol SynTrans 75w-90 GL4 (99% sure it’s rebranded Motorcraft unicorn fluid) and it was the same result.

Great shifting to start with but not long lasting. Maybe my 6 speed is just too worn out and the friction modifiers can only do so much.

 

I've been using Motul 300 for years, and heave always had some notchiness in my 6sp. I just switched to Amsoil 75/90 and so far haven't noticed much difference. I guess my trans is just "tired" after 22 years of "enthusiastic" use.