which weight gear oil
- Thread starter hotrodjohn71
- Start date
Dobie Gillis
Well-known member
Not that stuff, it's hypoid. Here's what I use in my T-85 w/OD: https://www.tractorsupply.com/tsc/p...actor-all-mineral-90-transmission-fluid-2-gal
rotorwrench
Well-known member
GL-5 is hypoid and GL-4 is mild EP. The package states hypoid but most folks would agree that it is a step less on EP than GL-5. The operator's manual generally specifies SAE 80 for winter or cold weather and SAE 90 for summer or warm weather. The rear axle can use GL-5 if you want since it has no bronze bushings in there. The transmission should use mild EP or GL-4. Original spec was GL-3 but it is obsolete. GL-4 replaced GL-3 and does have more EP additive than GL-3 did but not lot more.
A good quality SAE 50 motor oil will work for a transmission since it is the same viscosity as SAE 90 gear lube. It's somewhere between straight mineral GL-1 and GL-4 but it will work if you don't abuse it. I use Aero Shell W100 aviation oil in my overdrive transmissions and it works well. If a person goes the aviation oil route just make sure and avoid any oil with Lycoming TCP additive in it. The W100+ (or plus) is one to avoid.
A good quality SAE 50 motor oil will work for a transmission since it is the same viscosity as SAE 90 gear lube. It's somewhere between straight mineral GL-1 and GL-4 but it will work if you don't abuse it. I use Aero Shell W100 aviation oil in my overdrive transmissions and it works well. If a person goes the aviation oil route just make sure and avoid any oil with Lycoming TCP additive in it. The W100+ (or plus) is one to avoid.
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hotrodjohn71
New member
Thank you kindly guys. Just can't buy the mineral stuff at the local auto supply these days I guess...times change.
I'm gonna return the Sta-Lube back to napa and next time I head out of town, I'll stop by s tractor supply and get some 90w like you shared.
Thanks
I'm gonna return the Sta-Lube back to napa and next time I head out of town, I'll stop by s tractor supply and get some 90w like you shared.
Thanks
50fordcoupeman
Well-known member
NAPA should be able to get GL-4 for you..........they do here.
rotorwrench
Well-known member
That Sta-Lube photo in post #1 has the GL-4 on the package. It is useable even if it does have the term "hypoid" on there.
Kahuna
Well-known member
I use a NAPA product with a 75-90 rating in my 4 speed transmission, Overdrive adapter, Overdrive, and Banjo rear axle.
Has been working fine for the last several years & makes it easy to have just one lubricating fluid for everything except the engine. I use 5-30 in that.
Has been working fine for the last several years & makes it easy to have just one lubricating fluid for everything except the engine. I use 5-30 in that.
slumlord44
Senior Member
Valvoline makes a synthetic that is made for the old transmisions with brass syncro rings. Don't recall the name.