spraying rear diff oil after new driveshaft

[scott2093]

I get shivers when thinking about driveshafts. Doing 80 down a highway and seeing a driveshaft launch 20 feet in the air heading and vehicles with their windshields behind you.

 

[95Noobie]

Fortunately when my son's driveshaft let loose it must have split the outer 'ears' slightly first as it remained attached but was making a vibrating whacking sound. It gave him enough time to get to the off ramp, then could go about 1/4 mile at slow speeds up the road until it finally separated and the rear was dragging. By the time he figured out how to keep truck from rolling when he let off the brake (got a friend who came up behind him and stopped to help out swap positions in the cab and hold the brake) he finally saw the shaft on the ground. It does worry me too that you can't put a lot of torque on the yoke nut or harm the pinion bearings behind it, or that there is no cotter pin involved in securing the nut.

 

[0xDEADBEEF]

Similar thing happened with my sons truck. When we bought it the rear u joint was shot and banging around for who knows how long. Pinion was leaking badly. Fixed that, but about 4k miles later the new u-joint broke. Fixed it again, but the pinion was now wobbly and there was gear oil sprayed all under the bed. It was done.

 

[95Noobie]

so is it involved to replace the pinion gear? Or at that point do you look for a donor rear axle to get a new set of rear end gears?

 

[1998_K1500_Sub]

Happy to be pointed to a source for the service manual if it is on this forum already?

The factory service manuals can be found and downloaded from here, in searchable .pdf format.

88-98 Service Manuals​

 

[RShrimp]

I went the doner axle route because it was $300 and I got to pick my ratio. I just added all new brakes and seals and done. You should leave R&P install to pro.

 

[KansasOBS]

It does worry me too that you can't put a lot of torque on the yoke nut or harm the pinion bearings behind it, or that there is no cotter pin involved in securing the nut.

I'm a little late to the party, but technically you can pull the carrier on a 10bolt pretty easy, its just shims that you keep track of where they came out of, since making no changes really. Preload could then be somewhat checked, but not sure I'd sweat it.

You can can make it pretty tight, I think there might be some general torque recommendations on seal replacement you can find, I don't know offhand for your diff, but it takes a lot of force to crush the sleeve, and even more so when they have been work hardened to an extent when installed the first time. Talking real strong impacts, or 3 foot+ breakover bars cranking the hell out of it, etc. There is a reason for no cotter, you don't want to set the pinion depth, and then have to back it off, or crank tighter. Its a locknut.

 

[Schurkey]

so is it involved to replace the pinion gear? Or at that point do you look for a donor rear axle to get a new set of rear end gears?

VERY involved. It's easy enough to slap new parts into the axle housing. The tricky part is getting the pinion depth correct (every one needs some precision measuring and shim-selection to get it right) and then getting the pinion bearing preload correct, which involves a new crush-sleeve or aftermarket spacer/shim system.

Neither of those is "easy" or "fun", and both have to be near-perfect.

So, yeah, a used-but-usable axle of the correct width and gear ratio is usually selected. Clean the magnet, clean the housing, fresh lube, fix the worn-out brakes and verify the axle bearings and axle shafts are in good condition. Maybe replace the axle seals while you have the cover off and easy access to the C-clips (if used.)

 

[95Noobie]

Thanks to all for the added information and reassurance. We tightened the nut by hand the first time using an online torque recommendation of around 100 ft/lbs. Hard to truly get torque on it as the gears move a bit as you add torque. The second time after getting proper seal in there I just did snug and a little more. You mention the nut is a locking nut but I see no features of the original nut or the dorman replacement nut that show an ability to lock itself (no vinyl locking ring visible) I'm hopeful now that I didn't cause any damage in the install process as it seems like I would have had to put quite a bit more extreme force on the nut which we did not do.

However I do worry about the possibility that the pinion gear itself could have a wobble from the time when the shaft was banging around. My son is driving the truck to school today and we'll see if we can spot any fresh oil slinging around. No drips just sitting in the driveway a few days.

Rshrimp, curious, what was your original gear ratio and what one did you switch to (I guess and why?)

Thanks for the link to the manual and will keep that very handy in the future.

 

[95Noobie]

Bad news, my son says fresh oil spraying around on the way to school this morning. UGG, double UGG!!! Now how to find the leak? I know we have the right seal and new yoke and everything in place. No leaks out the diff cover as we replaced gasket and bolts and that side is not leaking. I can check the breather tube when he gets home. Otherwise how do I determine if it is coming around the spline shaft of the pinion gear? With yoke off is it pretty easy to feel if there is slop in that pinion spline shaft from the yoke side or do you have to open up the diff cover to inspect?