U-joint / Differential Help

bronyaur · May 25, 2010

My '95 Suburban K1500 has a grinding noise coming from the rear end. It's not constant - more like a shin-shin-shin that changes increases/decreases with vehicle speed. I haven't taken off the rear wheels yet to see if it's a brake shoe or something (rear brakes were replaced about 25,000 miles ago). The first thing I did was crawl under and check the u-joint. Oddly, the u-joints feel sound, but the part that goes into the differential feels sloppy. I don't have much experience with rear-ends, so I'm not sure if this is an issue. It seems like it should be an issue. Any thoughts? Here's a link to a video:

P.S. - Vehicle has 130,000 miles

bossier62guy · May 25, 2010

My '95 Suburban K1500 has a grinding noise coming from the rear end. It's not constant - more like a shin-shin-shin that changes increases/decreases with vehicle speed. I haven't taken off the rear wheels yet to see if it's a brake shoe or something (rear brakes were replaced about 25,000 miles ago). The first thing I did was crawl under and check the u-joint. Oddly, the u-joints feel sound, but the part that goes into the differential feels sloppy. I don't have much experience with rear-ends, so I'm not sure if this is an issue. It seems like it should be an issue. Any thoughts? Here's a link to a video:

P.S. - Vehicle has 130,000 miles

Looks like you've got too much slack in the pinion to me....possibly bad bearings.

bronyaur · May 25, 2010

Looks like you've got too much slack in the pinion to me....possibly bad bearings.

Any idea what is involved fixing that?

I'll get the back wheels off tomorrow to see if there's anything obvious making the grinding noise.

bossier62guy · May 26, 2010

Looks like you've got too much slack in the pinion to me....possibly bad bearings.

Any idea what is involved fixing that?

I'll get the back wheels off tomorrow to see if there's anything obvious making the grinding noise.

Setting the gears up once the repair is made is the critical part. I would personally have someone that knew what they were doing repair it, otherwise it could turn out to be a waste of time and money. Maybe that's not your problem but from your video it does seem like you've got way too much slack there.

txab · May 26, 2010

My '95 Suburban K1500 has a grinding noise coming from the rear end. It's not constant - more like a shin-shin-shin that changes increases/decreases with vehicle speed. I haven't taken off the rear wheels yet to see if it's a brake shoe or something (rear brakes were replaced about 25,000 miles ago). The first thing I did was crawl under and check the u-joint. Oddly, the u-joints feel sound, but the part that goes into the differential feels sloppy. I don't have much experience with rear-ends, so I'm not sure if this is an issue. It seems like it should be an issue. Any thoughts? Here's a link to a video:

P.S. - Vehicle has 130,000 miles

Looks like you've got too much slack in the pinion to me....possibly bad bearings.

+1

That sucker needs to be repaired soon.

bronyaur · May 26, 2010

Setting the gears up once the repair is made is the critical part. I would personally have someone that knew what they were doing repair it, otherwise it could turn out to be a waste of time and money. Maybe that's not your problem but from your video it does seem like you've got way too much slack there.

Good advice. I was thinking that if it was a u-joint or axle bearing I'd probably have a go at it myself, but ring & pinion are new territory for me. I'll see if I can find any other problems tomorrow, then make a plan from there. Thanks for the tips.

By the way, I was just doing some reading and have seen several suggestions that a howl coming from the rear end under acceleration is almost always a pinion bearing. My Suburban has been howling for several months, but only when the accelerator is applied. As soon as I let off, it goes quiet. That, coupled with what people are seeing in the video, may very well be my issue. I haven't been real sure where the howl is coming from, but suspected the transmission or transfer case. Now that the grinding noise has started it definitely sounds further back.

Also, since the grinding noise is not continuous, but grind-quiet-grind-quiet, changing with vehicle speed, I'm starting to worry about a section on my ring gear. I may have to pull the cover tomorrow just to see if there's anything obvious.

Again, I'll report back tomorrow.

Willshire · May 26, 2010

I have been collecting info on rear ends for the past few days. The eaton posi went on mine so i am buying a used axle with warranty for about the same price as a rebuild. I picked up a rear end for 1100 cdn with 160k on it. My thought here is, to change a rear end the truck will be down for about 3 hrs. to rebuild a rear end, if all goes well would be at least a day imo. This way i can rebuild the old rear end and still drive my only mode of transportation. Setup of the backlash between the ring and pinion should be between .006 and .010 inches and slightly beyond my skills.

bronyaur · May 26, 2010

I found the problem. Now I just have to weigh the cost of having the rear end rebuilt compared to finding a replacement I can swap myself. Thanks for the help.

J-man67 · May 26, 2010

No crap...sheared some teeth. Have an need for something more HD? Could always swap a 14 bolt in there. They are BEEFY. Finding a used one local might be less then new gear and install.

Willshire · May 26, 2010

i just called to have true eaton posi and new 3.73s put in $1400cdn. junk yard rear end was 1150 so for 250 i can put what i want in there

bronyaur · May 26, 2010

No crap...sheared some teeth. Have an need for something more HD? Could always swap a 14 bolt in there. They are BEEFY. Finding a used one local might be less then new gear and install.

For the most part it's a grocery-getter, but I do tow my boat with it. I've got a line on a used direct replacement about an hour away for $750 + tax.