Salisbury differential IRS lubrication

[1985 CCX]

So when adding lubrication to T10 and Toploaders it’s not a synthetic lubrication application. They require old school petroleum based gear oil. Think synthetic will toast synchros.

When adding oil to differential is that the same?
Or can one use newer blends?
Experience out their?

I used Lucas pictured and the std Motorcraft additive.

Thoughts?
Anyone feel this is a mistake?
Just don’t want to roast the Diff.....

[Grubby]

The Salisbury is a Dana 44 built under license. Modern Dana 44s in Jeeps call for synthetic gear oil.

I say synthetic is acceptable as long as you use the correct additive for your posi traction clutch packs.

I personally use conventional gear oil in mine. It lasted all these years with it. Why waste money on synthetic?

John

[1985 CCX]

I hear that, it’s all they had when I stopped.
I’ve always used climbing oil, with Ford additive.
Now I question after it’s in.
If there are bad experiences I’ll dump and do over.

[HTM101]

Deleted.

[eschaider]

I think the only possible risk might be to friction surfaces, like posi clutches, and I am not certain about that, Jeff. If you want positive confirmation you might consider giving Lucas a call and I suspect they will provide you the best guidance possible.

I am in the same camp as John (Grubby) with respect to synthetics in the diff. Someone once told me the synthetics would run cooler but I am not certain about that. I do know I have had three daily drivers I drove over 300K miles each, that did not use synthetic in the diff and also did not have any problems.

[Unique427]

Have always used standard gear oil without issue.

As mentioned, synthetic may run cooler but never
had any problems with high differential temperatures.

I slapped a couple of these stickers on the differential to monitor any change.
https://www.thermometersite.com/ther...sible-labels-2

[1985 CCX]

I am not worried about differential temperatures just worried more about something go wrong because I put the synthetic into Diff. Not sure they’re like the transmission on a Toploader in a T10 Where you don’t wanna use synthetics this is an older differential circa 70s so I figured I’d ask if there’s any experience out there but giving Lucas a call might be the best.

Again I bought it because they didn’t have regular petroleum base at the auto parts store when I was there and I wanted to just get it done...��

[joyridin']

I ran synthetic in my Salibury for many years until I rebuilt it. I never saw any wear on the clutch disks and it surely didn't hurt the bearings.

Certain types of clutch disks don't like synthetic, but the Salisbury style is not fiber, so there shouldn't be any issues.

[strictlypersonl]

A good synthetic oil should work fine. In the Salisbury, just remember to add friction modifier for the limited slip.

[1985 CCX]

Great advice, yup added the Motorcraft ... too

[LMH]

Jeff, my 2019 Jeep Wrangler calls for 75w-90 synthetic with the friction modifier and it’s a Dana44. Not sure how different that would be to your differential but can’t much as far as internals go.
Larry

[1985 CCX]

Sounds like I am good, thanks a bunch guys!

[Riverside racer]

I have always broken in my lsd diffs using mineral oil 90w and after a 1000 miles drained and refilled with the same but plus friction modifier. Never had an issue.

[MAStuart]

Think the big deal is that a lot of the gear oil on the market is not compatible with brass. So get the right stuff for your toploader or T10.

[patrickt]

Originally Posted by Riverside racer

I have always broken in my lsd diffs using mineral oil 90w and after a 1000 miles drained and refilled with the same but plus friction modifier. Never had an issue.

Ever since the early 60's most Owner's Manuals, if you flip to the back and read the recommended service intervals, have a "fill for life" no service required for non-limited slip rears, but for LSDs they recommend one single change out at the 7,500 mile mark along with the additive. If we go wayyyyyy back to 1963 and Jaguar's Powr-Lok (which a lot of have in our Cobras), you'll find this little gem: