The Ford Barn

hotrodjohn71 · 08-10-2018, 11:25 AM

1956 Ford F250 pickup truck.
Which weight of non sulfur (GL-4) gear oil would you recommend for T98 4 speed trans and Dana rear?

How about this stuff??? California.

Dobie Gillis · 08-10-2018, 01:38 PM

Not that stuff, it's hypoid. Here's what I use in my T-85 w/OD: https://www.tractorsupply.com/tsc/pr...on-fluid-2-gal

rotorwrench · 08-10-2018, 04:26 PM

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 Original spec was GL-3 but it is obsolete.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.

hotrodjohn71 · 08-10-2018, 09:04 PM

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

50fordcoupeman · 08-10-2018, 11:30 PM

NAPA should be able to get GL-4 for you..........they do here.

rotorwrench · 08-11-2018, 08:42 AM

Sponsored Links (Register now to hide all advertisements)

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 · 08-12-2018, 01:17 AM

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.

bobss396 · 08-12-2018, 08:13 AM

I use a Richmond GL4 in my 4-speed, have also used a Brad Penn product. For the posi rear, I went with some Valvoline product.

slumlord44 · 08-12-2018, 10:45 PM

Valvoline makes a synthetic that is made for the old transmisions with brass syncro rings. Don't recall the name.

08-10-2018, 01:38 PM	#2
Dobie Gillis Senior Member Join Date: May 2012 Location: Middle TN Posts: 1,060	Re: which weight gear oil Not that stuff, it's hypoid. Here's what I use in my T-85 w/OD: https://www.tractorsupply.com/tsc/pr...on-fluid-2-gal __________________ Often wrong but never in doubt.

08-10-2018, 04:26 PM	#3
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,442	Re: which weight gear oil 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. Last edited by rotorwrench; 08-10-2018 at 06:07 PM.

08-10-2018, 09:04 PM	#4
hotrodjohn71 Junior Member Join Date: Aug 2018 Posts: 2	Re: which weight gear oil 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

08-10-2018, 11:30 PM	#5
50fordcoupeman Senior Member Join Date: Mar 2016 Location: LaGrande Oregon Posts: 866	Re: which weight gear oil NAPA should be able to get GL-4 for you..........they do here.

08-11-2018, 08:42 AM	#6
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,442	Re: which weight gear oil Sponsored Links (Register now to hide all advertisements) 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.

08-12-2018, 01:17 AM	#7
Kahuna Senior Member Join Date: May 2010 Location: NorCal Posts: 2,617	Re: which weight gear oil 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.

08-12-2018, 08:13 AM	#8
bobss396 Senior Member Join Date: Aug 2014 Posts: 721	Re: which weight gear oil I use a Richmond GL4 in my 4-speed, have also used a Brad Penn product. For the posi rear, I went with some Valvoline product.

08-12-2018, 10:45 PM	#9
slumlord44 Senior Member Join Date: Jun 2017 Posts: 104	Re: which weight gear oil Valvoline makes a synthetic that is made for the old transmisions with brass syncro rings. Don't recall the name.