[Doosenberry]

I would use an 80w90 conventional gear oil of your choice. I'm assuming that was what was used when these were new or something close to it.

I know Eaton does not recommend synthetic gear oils with their Truetrac and Detroit lockers, so I'd imagine if conventional is good enough for them then it's probably good enough for your lock rite.

Link for reference to my Eaton claim for the skeptics. lol.

Performance | Aftermarket | Differentials | Install Kits | Eaton

www.eaton.com

 

[Doosenberry]

That's essentially what I was told at my local 4x4 shop when I asked about gear oil for my new gears/lockers. The guy said as long as I was changing it that it was less of a concern as long as the oil was of good quality. Gear oil is probably the least changed oil in any DD vehicle.

 

[Doosenberry]

That or the MT90. They both say they are safe with brass parts.