[dkb111]

What gearbox lube have you had good experience with (Alfa synchros, not dogbox) for racing?

Regards

David

p. s.-- John Cullen / Jack Beck recommend Redline MTL (70-80, GL4).

Redline recommends 75-90NS (GL5) based on Alfa's original spec of GL5 lube and Porsche/Alfa-type synchros.

 

[Alfar7]

Transaxle/transmission Lube

Redline recommends 75-90NS (GL5) based on Alfa's original spec of GL5 lube and Porsche/Alfa-type synchros.

75-90 NS is the only lube I ever have reccommended for these Transaxles/Gearboxes.
MTL works, but is too thin (viscosity) even at 70-80 or 90 wt. It is about the viscosity of 10W40 motor oil. The gears need the heavier lubricity & the syncros & LSD clutches need the additives. With the thinner lube temp is higher.

This has been covered numerous times, on the BB and Alfa racing list. GL ratings have changed over the years. What is now GL5 was GL6
The correct lube for 105 & later cars up to the syncro design change for the front wheel drive cars is GL4. GL5 is too shear resistant for the syncros to work.

 

[BlpltGTV]

I'd stay away from Redline. I did use it for a few years, but when I nuked yet another 5th gear in my Datsun roadster 5spd (a Porsche designed steel syncro box) I decided to look else where. My syncros were showing much more wear than they should as well. On the syncros, I double clutch or heal and toe all my downshifts. (A habit learned while learning to drive in a car with a worn out transmission.) I have now gone to SWEPCO. Pelican parts sells it. Its about the same price as Redline, but all the Porsche guys swear by it. I've been happy with it in the roadster. It takes a little while to warm up, but is nice once warm.

Will

 

[dkb111]

Thanks Richard.

Will, which redline were you using?

David

 

[BlpltGTV]

I had the last failure with the shockproof redline. That I had just changed 2 days before. The others I was running the 80/90NT I think (what ever the GL5 is that isn't MT90) The guy who built my box has seen other strange failures in transmissions that have run Redline as well, one of the reasons he suggested the SWEPCO.

Will