differential oil

[Gerry]

What oil do you recommend for the differentials. 80- 90 synthetic?
Thanks,

[Cal_Gary]

I use the conventional 80-90 GL5.
Gary

[MSeriesRebuild]

What oil do you recommend for the differentials. 80- 90 synthetic?
Thanks,

Royal Purple MAX GEAR 75-90 is the top of the line for diff use.

[Gerry]

how much will both diffs take?
Thanks,

[cuz]

Pg 77 & 109 of TM 9-8031-2 6 pints each.

Pg 18 of TM 9-8030 New fill 3 Qts and refill 2.5 Qts.

[MSeriesRebuild]

how much will both diffs take?
Thanks,

If you are simply pulling the drain plug, there will be a little over 1/2 a pint of oil that will not drain as the plug is not at the lowest point in the housing. If you are changing oil types, it would be best to do 1 of 2 things, either pull the diff out of the axle housing for a good cleaning and visual inspection, while it's out you can get all the oil and debris that won't drain cleaned out. You can also drill and tap a new 1/4"NPT drain hole at the bottom of the rear portion of the housing that will allow all oil to drain. The civilian power wagons are all done this way, it eliminates the issue of an incomplete drain, and is little trouble to do. We have done many along with adding a magnetic drain plug, it works nicely. With a complete drain accomplished, each unit will take approximately 3 quarts to refill to plug level.

[Gerry]

Thanks all for the info!!!!