Differential Lube

[djbr459]

Hi all,
Looking for recommendations on differential lube in an 8 3/4, 3.23 posi unit.
Thanks

 

[dadsbee]

Cheap old 80W90 dinosaur gear old for hypoid and a bottle of whale oil. DO NOT use synthetic...

 

[Geoff 2]

Redline 80w/140. Suitable for std & LSD diffs. Been using it for 25 yrs. It quieted down the slight gear whine I had that conventional oil wouldn't.

 

[66Satellite47]

The 80-90 should be fine. If you have the clutch style limited slip, you want the friction modifier too. The Ford style works really good, maybe Mopar if they still have it.

 

[33 IMP]

Dino oil, and Motorcraft friction modifier. No synthetic!
I had a friend who owned a rear-end shop, specializing in racing 9"ers, but worked on everything. He would warrantee a rear-end job for six seconds, six feet, whichever came first, if the customer insisted on synthetic gear lube.

 

[djbr459]

Thanks for the replies.
I was thinking about synthetic but not now based on your recommendations.

 

[66Satellite47]

FYI, I did switch to synthetic in my Dana after installing the spool. Limited slip, no.

 

[Geoff 2]

There is nothing wrong with syn lube for the rear end. The Redline quoted above is designed for LSD & has the correct additives. There are also many other brands available. Much better to buy an oil, syn or min, that has the LSD additive added rather than guesswork adding somebody else's product....
I have used RL for over 20 yrs, weekly driver.
Rear end builders who live in the past probably still think the flat head Ford is the one to beat...

 

[66Satellite47]

In the past the LSD additive in most gear oils was not correct for some types of limited slips. What worked for a cone type Mopar LSD didn't for a clutch type. What worked for a GM didn't for a Ford or Mopar clutch type. Maybe things have changed now, I don't know.

 

[Longknife]

Hi all,
Looking for recommendations on differential lube in an 8 3/4, 3.23 posi unit.
Thanks

Clutch or cone????? BTW That is a SURE GRIP,,,, Only Shivvys' have a POSI!!!!!

 

[Cranky]

Hi all,
Looking for recommendations on differential lube in an 8 3/4, 3.23 posi unit.
Thanks

Don't know what GM uses in their 'posi' units but the Mopar stuff worked in their Sure Grip units

There is nothing wrong with syn lube for the rear end. The Redline quoted above is designed for LSD & has the correct additives. There are also many other brands available. Much better to buy an oil, syn or min, that has the LSD additive added rather than guesswork adding somebody else's product....
I have used RL for over 20 yrs, weekly driver.
Rear end builders who live in the past probably still think the flat head Ford is the one to beat...

I used the Mobil 1 full syn with the LSD additive in it and well, my clutch type SG chattered like a pissed off squirrel. Went to to the regular stuff with 2 bottles of the Mopar stuff (Dana 80 takes more) and it quit chattering in the first turn.

 

[djbr459]

Sorry, it's a cone type sure grip

 

[66Satellite47]

Sorry, it's a cone type sure grip

Then it can probably use any of the gear oils that say they are for limited slip.

 

[hunt2elk]

I use what Cass, aka Dr. Diff recommends. Super Tech 85w-140 conventional gear oil (sold at Walmart) along with a bottle of Ford friction modifier.

 

[Longknife]

Sorry, it's a cone type sure grip

I just received a cone type differential from Mikes Custom Differentials and he recommended this.https://www.ebay.com/itm/2748198896...1291&msclkid=22b838f566821924b9ca5a51f5bc414c