My current truck is a 2000 GMC 2500 with 224000 miles on it. It's treated me well but has been making intermittent grinding noises for the past six months or so. The noises weren't based on RPMs or speed and I just couldn't track down the source. Yesterday, I got in it and drove 10 feet and the whole truck began shaking, violently. Wondering if it was another intermittent symptom of its age, I drove it around the block. No improvement. So, I took a look underneath figuring it was a wheel bearing and race. Nada. I smelled hot rubber so I sniffed around each tire but the smell wasn't coming from there. I checked the universal joints on the drive shaft but they looked ok. Then I noticed the center bearing on the drive shaft was smoking like crazy. That sucker was seized up hard and started burning the rubber piece around it. Nice to have a burning part next to the gas tank, huh?

I never dropped a drive shaft before but it was pretty straight forward. I marked it with chalk because i didn't know if it was balanced in a certain configuration. The local AutoZone actually had the part in stock. I argued with the lady that I have a K2500 but she assured me that it is a C2500 and gave me the wrong part. I only found out after cutting and chiseling the old bearing off and sure enough the new bearing I.D. was too small. They exchanged it for the correct part and the entire repair only cost about $30. The bearing went on with a hammer and PVC pipe. Easy.

It all buttoned up except the wheels must have moved against the chocks because the differential connection moved a couple degrees and I had to push the truck and have little Mark kick the chocks under the wheels until it moved enough to bolt up.

Now the truck doesn't make weird grinding noises and I don't want to get rid of it anymore.

Do I have to torque the driveshaft bolts to a certain or at least equal ft.lbs.? Do I have to use any thread lock? I'll check them over the next couple of days to make sure they don't loosen but any advice is appreciated.

Locktite is probably a good idea, though I’m sure I didn’t use any on the one I did forever ago and I don’t recall anybody using it for ujoints when I worked in a shop about the same time. If you can find the correct torque spec, that might be a good idea, though I suspect we just used tight enough that the bolts won’t come lose, but not so tight that we sheared the bolts.

It sounds to me like you have the problem solved.

Drive shafts are balanced and phased.
The phasing is required because the harmonics result in the whirling (whipping) of the shaft.

With high speed cameras, shafts out of phase, often look like a noodle.

So, you did the right thing in marking the assembly.

The "U" straps should only be snugged to about 20ft lbs, and use self locking nuts. Over torquing distorts the caps and result in accelerated fretting of the bearings.

quote:

Originally posted by sigmonkey:
Drive shafts are balanced and phased.
The phasing is required because the harmonics result in the whirling (whipping) of the shaft.

With high speed cameras, shafts out of phase, often look like a noodle.

So, you did the right thing in marking the assembly.

The "U" straps should only be snugged to about 20ft lbs, and use self locking nuts. Over torquing distorts the caps and result in accelerated fretting of the bearings.

I tightened them but didn't go nuts on them. I don't know what fretting is.

Sounds like a good job Mark. So no new truck or on the back burner now?
Grease the DL. No body does, but everybody should.

quote:

Originally posted by old rugged cross:
Sounds like a good job Mark. So no new truck or on the back burner now?

The funny part is that I went up to the dealership, in this truck, a few hours before this all happened to build out my new work truck. I think this old girl heard that I was replacing her and she threw a fit.

They offered me $300 on a trade-in.

quote:

Grease the DL. No body does, but everybody should.

Quick, tell me what DL means and I'll do it if I didn't.

Driveline. Hit all the grease zerks on your driveshaft/u-joints.

300 bucks? Did you laugh at them?

quote:

Originally posted by M1Garandy:
Driveline. Hit all the grease zerks on your driveshaft/u-joints.

If there are any grease zerks. Most factory stuff is sealed these days, even a lot of the aftermarket.

Anecdote:
I had a hand me down ‘78 Chevy pickup w/ an Olds diesel. It was very hard on rear u-joints. I carried a full set of tools and more than a few spare parts with me in college. Once, while replacing my rear u-joint in the dorm parking lot, campus security came by and told me I couldn’t work on my vehicle there. I looked up from my tailgate/workbench and said “sorry, officer, as soon as I get this put back together, I’ll move it”
He winked, said “ok, thanks” and drove off.
I did move to another parking spot in the same lot after I finished.

Lots of fond memories of that truck. Dad bought it new. It had over 400k on the chassis when I started driving it. I built the engine out of a pile of spare parts we had in the corner of our shop.

quote:

Originally posted by M1Garandy:
Driveline. Hit all the grease zerks on your driveshaft/u-joints.

Oh, yeah. I definitely took care of that. Of course it's the first time I did it in 10 years.

quote:

Originally posted by shovelhead:
300 bucks? Did you laugh at them?

Yeah. That's scrap pricing there. I'd rather give it to my friend's son that just turned 16.

It would be a good idea to use threadlocker on the threads and torque the bolts.

quote:

posted July 14, 2019 07:01 PM Hide Post
Driveline. Hit all the grease zerks on your driveshaft/u-joints

Zactly

quote:

They offered me $300 on a trade-in