The GMC CCKW

How hard is it to replace the inner wheel seals when you have all of the rest done up? When my dad and I did the axles the inner seals looked good so we assumed they were until we filled them with gear oil and it is very embarrassing going to parades and car shows and have people tell me that I'm leaking.

It almost looked like you could replace the inner seals without having to take your wheel apart looking at the front wheel it is in two pieces and it slides into place I'd assume the back is the same if I'm correct?

not sure which seal you are talking about but, the wheel bearings and front knuckles have grease in them, not gear oil

The front seals on the CCKW seem to be one of those things that generates a lot of confusion. I can't speak to the split design. However, I have done some work on the banjo front axle in my truck. To make sure that we are on the same page, here is a diagram from TM9-1801.



R, and Z thru AE constitute the "outer" seal. It seals the knuckle to the end of axle housing. Its primary job is to keep contaminates out of the CV joint (S,T,U,V), the trunnion bearings (AG, AH) the thrust washer surfaces (J, X) and the axle shaft bushing (I). It also contains the grease (not oil) used to lubricate these components. If you have oil in this space, then either someone misread the lubrication order and filled it with gear oil, or the inner seal is leaking (see next paragraph).

The "inner" front axle seal can be seen as "Y". This seal is pressed into the end of the axle housing - one per side. This seal's ID contacts the inner axle shaft OD, and keeps the gear oil from running out the end of the axle tube. When this seal is leaking bad enough you get gear oil running down the inside of your front tires whenever you park.

Lastly, there is the seal that you are probably already very familiar with, the one on the hub - or "K" in the following image:



To add to the confusion, the manual calls this an "oil seal". However, it is not really holding back any "oil", only wheel bearing grease. When this seal leaks, you will have wheel bearing grease all over your brakes.

My inner oil seals were leaking badly, and I can tell you first hand that it is a pretty time consuming job to replace them. Nothing particularly difficult, you just have to remove a lot of parts to get to them. Plus, while you're in there and have everything apart, that's the time to clean, inspect and re-lube everything (make sure you have a good supply of rags). BTW, per Dr. Deuce's recommendation, I installed two 0.250" width seals per side as opposed to the single wide seal. I think that this will work better as the new seals will ride on a "fresh" surface - as opposed to the path worn by the old seal.

Best Regards...