In my experience this removed gear grind and made shifting SUPER smooth in 4 different cars, has anyone tried or know if FDs can use this in the tranny?

 

So does Redline MT90...

 

I tried it before and didn't really like it on cold start in the morning. Once the car warmed up properly, it shifted like normal. Didn't see much of a difference but it caused med to warm the car up longer just to avoid the notchy feeling of 1st and 2nd gear.

Stick with Redline MT90 or Royal Purple

 

I used it and didn't like it. Plus it contains additives that attack the brass synchros. It is very good for the diff however.

MT-90 is the best of the Redline oils for our transmission.

David

 

I'm pretty sure you are talking about synchromesh, lightweight shockproof doesn't eat the synchros I've used it in my wrx for over 80k, checked every 20k no shavings at all. I will try MT-90 for the RX7 though

 

Synchromesh is a Pennzoil product and I've never tried it. Shockproof has solids in it that inhibit synchro action plus active sulfur/phosphorus in the EP package that are not good for brass.

Of course it's all relative, but I talked with the guys at Redline for a while and they were pretty convinced on MT-90.