1971 Loadstar 4 spd gearbox fluid

[Aruba1]

Sorry about the basic question but I searched on the internet and found no answer. What is the transmission fluid type that is required in the 4 spd manual transmission of the loadstar?

 

[cole in mo.]

Always ran 85-90 in our older 4 and 5 speeds.

 

[old]

The 80W-90 or the newer 85W-140 is just fine.

 

[Jon Hagen]

Many specify a 50wt non detergent motor oil, but 80-90 GL4 or lower gear lube is OK. I have used 80-90 GL5 gear lube in them myself without problem, but a GL5 gear oil has a sulfer based extreem pressure additive for hypoid rear end gears that they tell me will attack white or yellow (aluminum or brass) bushings, thrust washers or syncro blocker rings, so use a GL5 gear oil at your own risk. They claim that condensation moisture combined with the sulfer additive in GL5 oil, produces sulferic adid that attacks the white and yellow metal.

 

[Aruba1]

Really good responses, I'll need to check around for GL4 fluid. Thank you, Gio

 

[Duner Wi]

Check with Napa for Sta Lube 85W90 GL4.
They should have it in 1 or 5 gallons. More than likely have to order it for overnight delivery.
I have seen GL-4 90wt at Autozone made by Coastal in 1 gallon jug.

 

[rusty6]

I use a straight #30 motor oil in my 71 Loadstar four speed trans. After reading an article at www.oldihc.org where they advised against using gear lube . Seems to working fine with the number 30 motor oil so I will continue.