Concerning Transmission and Transfer Case Rebuilds

[Phil Waterman]

The MB-C2 Lists 80 or 90 Hypoid for Gear Oil the MB-C1 says the same for differential and transmission but list a separate one for the transfer case all the manuals talk about thinner lube for winter use. The GM 1940 manual for regular cars and trucks list summer S.A.E. 90, S.A.E. 140 or S.A.E. 160 the for winter down to 0F S.A.E. 80 below 0F S.A.E. 80 with 10% Kerosene. The one Ford manual I have give 80-90. I read all of this as meaning use the thinnest gear lube that doesn’t leak out to quick.

I have taken all my trucks over to S.A.E. 85W140 which seems to work pretty good, I do regular IR temperature readings on various components after long drives in my CMPs as a way of spotting problems the Transfer Case runs the hottest but the highest seen 140F.

If you can put the lube in warm, in the summer I put the 5 gallon pail in the sun for the day, in the winter I set it in front of the shop furnace out let.


What weight gear lube has been discussed in several different threads, generally related one theme it leaks. Below is a list of some those threads to get the collective wisdom.

www.mapleleafup.net/forums/archive/index.php/t-13708.html
www.mapleleafup.net/forums/archive/index.php/t-5435.html
www.mapleleafup.net/forums/showthread.php?t=12301&page=3 Steering

As to the 600X listed on MAC wish they had a real product data sheet on it.

Cheers Phil