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Have had a look around and cannot really find a definative answer, what grease is recommended for the front and rear hubs on a M38A1?

I would have thought the newer grease compounds are a little too viscous...
so what do guys recommend?

Thanks

Nic Jackson

Uh oh - there's that can of worms again!

Seriously though, there are 2 schools of thought there: oil or a grease/oil G.O. is better, but the next person might tell you the mixture is better.

The rear doesn't have knuckle oil - or a knuckle at all. Its bearings are lubed by the differential oil.

I used a mix of 140w G.O. and wheel bearing grease - makes like a 2-300w G.O. - barely moving grease. Just remember to grese and adjust your upper kingpin bearings before you use this method - I had to replace mine because there was "cake" type grease in my hubs (in other words, hadn't been serviced in many years!).

Hope this helps

The knuckle design was not meant to carry a liquid grease. The original Army plan called for frequent disassembly and hand packing with #2 chassis grease. This is still the most reliable lubrication plan. Problem is folks today are raised on electronic ignition and permanent lubed joints and they abhor this repetative lubrication program so they have improvised over the years with various gooey contraptions. The knuckle spheres must be in excellent condition (smooth as a baby's bottom) with quality seals and seal retainers or this gooey mess ends up on the floor.

If you are in very cold climates the gooey stuff lets the axle turn easier. Hot climates you are better off with any quality #2 sgli grease. In either case you must open the knuckle up and cleaned the steering pivot bearings and repack them with a #2 sgli grease at least every 6000 miles. Don't let that grease get to old on the calander either. About 4 years max. The gooey stuff will not sling onto these pivot bearings. They must be cleaned and packed by hand periodically.

The choices for gooey stuff are endless and everyone who uses a mixture will swear by it just as they do on Marvel Mystery oil.

I use John Deere Corn Head grease in the knuckles on both my M38 and M37, and in both steering boxes...the grease in NLGI 0, and is for use in low speed high impact applications...in your question, though, you say fron t and rear "hubs"...if you mean the lubing the bearings in the hubs, use wheel bearing grease...W

I believe if you look closely the rear axle has a plug or zerk at the outboard end through which you inject SGLI #2 with a hand grease gun being careful not to over service and push grease through the seal to the brakes. This is shown in the TM's.

Hi Wes...I don't know if it was a change to save money, or not, but on my M38CDN, the spring loaded vents are on top, but where the zerks would go, there are threaded plugs...W

The Army had the zerks removed because their junior mechanics were overgreasing them. Just remove the plugs install a zerk and grease only one to two pumps at 6000 miles then remove, clean and hand pack at 12000 miles. The earlier M38 TM9-804 showed the fitting.

Wes...since I had to replace all the bearings in the rear axle due to suspected water in the axle(even the pinion and carrier bearings had to be replaced), I did just that...the zerks for the outboard bearings get a couple of shots once a year...W

Man, I got that one wrong! I forgot about the inner axle seals - no G.O. can get to the bearings.

Just remove the plugs install a zerk and grease only one to two pumps at 6000 miles then remove, clean and hand pack at 12000 miles. The earlier M38 TM9-804 showed the fitting.

I guess it might be time to do mine - it is AT LEAST 15 years overdue! Maybe I'll pump a little grease in there and leave the hand packing for a late fall project!