8031C Auxiliary Transmission Lube

[tilynb61]

I have a 64 Mack B755, Quadraplex with a Spicer/ Brown-Lipe 8031C 3 speed Aux box. I am looking to change the lube in the aux box and am wondering what oil to use? I have heard either 50wt motor oil or 85/90 gear oil. Anyone have a manual or know which to use?

Thanks

[Brian Blaylock]

I have a rebuild sheet for the 8341 it says to use straight 30 weight

[57 bcr]

^{I always heard 50wt engine oil in Spicers,also.Too heavy (like 80/90) will not lube the needle bearings like the thinner oils.}

[Freightrain]

I put 50w motor oil in my 6xxx series box. Two years now without an issue.

I've heard with the needle bearings, thick grease will not work well especially in cooler climates.

[tilynb61]

Thanks for the help. Looks like motor oil it is.

[theakerstwo]

I put 50w motor oil in my 6xxx series box. Two years now without an issue.

I've heard with the needle bearings, thick grease will not work well especially in cooler climates.

We used 50W in them cause they have needle brgs.Aershell white lable is another 50W that we used in them as well as in road ranger trans.

[Dennis]

You need to use straight 50 wt motor oil, but the aviation oil (like Aeroshell) is preferred. Most of the truck parts stores sell 50 wt synthetic transmission oil which I think would be as good, maybe better, since synthetics weren't around when the auxiliary trans' were invented.