50wt in the Transmission

[shootiniron]

Anyone use 50wt gear oil in their transmissions?I use it in my M37 and was wondering if it work in the deuce tranny's.Thanks.

 

[JasonS]

50wt is what Spicer originally specified as recommended lubricant.

 

[Jake0147]

I've been wondering on that too... The trucks at work use it with greatly extended service life, but they're all ball bearings, not a bushing in them, so I dunno... I guess my interest is more in availability than in performance. I searched a long time ago and found a couple of respectable members in agreement that Spicer would have called out 50 weight, but "allowed" the use of gear oil to minimize the number of fluids required to keep on hand. They go forever with "old fasioned" TM recommended GL-1 in them and I can't ask for more than that, so I've got to be pretty convinced with something more than a fuel mileage gain before I consider switching.

 

[jatonka]

Spicer transmissions of the 50s, 60s, and 70s always specked 50 wt motor oil. While working in Alaska on the pipeline, we used all the way down to 10wt motor oil in cold weather. It has to be your call, it's your rig. JT out