90 wt HYPOID lube vs 80-90 GEAR oil
 

Maybe terminology has just changed, but I used the proper gear oil to fill my 3 speed w/od trans and now am ready to top off the diff with the specified 90 wt HYPOID lube. I have read the definition of Hypoid, it is for ring & pinion type gear sets. I am having trouble finding this, I see some marine applications, long story well long,... what are folks using for diff lubrication? Thanks!

Re: 90 wt HYPOID lube vs 80-90 GEAR oil
 

I use regular 80-90 gear oil

Re: 90 wt HYPOID lube vs 80-90 GEAR oil
 

The conventional wisdom is to use GL-4 gear oil in the trans and GL-5 gear oil in a hypoid differential like a shoebox Ford. (The banjo-type earlier differentials (spiral bevel, not hypoid) would use the GL-4.) Have not seen the word "hypoid" used much on labels, just the generic "gear oil" or similar designation.

Re: 90 wt HYPOID lube vs 80-90 GEAR oil
 

You need GL-4. GL-5 will attack the yellow metals in your trans. You can run GL-5 in the diff, but I keep it simple and put 140 GL-4 in the trans and diff. You can find the MasterPro brand cheap at Oreillys. I’ve read Van Pelt recommends 140 for the trans. I like the way mine shifts with it over 90 oil.

Re: 90 wt HYPOID lube vs 80-90 GEAR oil
 

exactly what i use in my '37 trans and diff. Tom.

Re: 90 wt HYPOID lube vs 80-90 GEAR oil
 

All good comments guys, thanks much. FWIW I found the Sta-lube line by CRC has various weights recommended for Hypoid gears as well as other applications.

Re: 90 wt HYPOID lube vs 80-90 GEAR oil
 

when the pinon gear is below the ring gear center it is a hypoid rear

Re: 90 wt HYPOID lube vs 80-90 GEAR oil
 

Millers oil options, I think you can get it on Amazon.

Re: 90 wt HYPOID lube vs 80-90 GEAR oil
 

Sta-Lube 140. Was easy to find, haven't looked for a while.

Re: 90 wt HYPOID lube vs 80-90 GEAR oil
 

O'Reillys sells GL-140.
https://www.oreillyauto.com/search?q...ckajYwJGwwJGgw

Re: 90 wt HYPOID lube vs 80-90 GEAR oil
 

If 140 works for you that's all that matters. That said, I was talking to Mac Van Pelt today regarding the 3 spd/OD trans he built for my '51 Tudor, and said to use GL-4 85-90 gear oil not 140, which is more for truck transmissions. I have a jug of Sta-Lube GL-4 85/90 coming.