Spitfire Spitfire 4 Transmission Fluid

[STL_Joe]

Recently pulled my transmission with the engine. Installed new slave cylinder, Throwout bearing(boy was that hard to find!), and throwout lever linkage. Drained it and filled with 85W gear lube from Advance Auto. Later was reading a catalog from a supplier in PA where they indicated that the new gear lube GL5 would eat up the brass synchro parts in my transmission and that I should use GL4 type. Need to check exactly what is in there but would like your feedback.

Thanks!

 

[TR3driver]

I believe the "GL5 problem" is real, but that it does not apply to all GL5 oils.

IMO, check your oil and see if it is also rated MT1. If so, it should be fine. Or at least corrosion of the "yellow metal" should not be a problem. Some synthetic GL5 oils are apparently also too 'slick' for good synchro operation.

 

[BRSLimited]

GL4 is still available but getting harder to find. I managed to find a supplier local to me but it's like $13/qt.

 

[dklawson]

You could try Red-Line MTL-90.
https://www.allraceoil.com/redlinemtlmt90.html

That is what is in our '72 Spit's gearbox.

 

[mgedit]

Bought this at NAPA a couple of years ago for TR6 diff.

I found redline to be too "slippy" in my non-OD TR6 transmission (slipped out of gear on downsifts to second gear). I use 30 weight non-detergent motor oil now new transmission in TR6 (with OD). Lots of discussion about which fluids to use, but I'd be cautious with GL5 products.

Cheers, Mike

 

[TonyPanchot]

13 $$ a Quart, you can afford that !

 

[billspit]

I bought the Stalube a couple of years from a NAP store ago for $12/gallon I think.

 

[Andrew Mace]

I bought the Stalube a couple of years from a NAP store ago for $12/gallon I think.

So did I, but that was then and this is now. I just saw it on the shelf at my local NAPA for almost $30/gallon! Fortunately, I've still got a good 1/5 qts left....