guesses are fine too.
Rear End Issues
Thread Starter
Burning Brakes
Joined: Jun 2004
Posts: 1,012
Likes: 5
From: Granbury, TX
Rear End Issues
I’ve had my '82 Vette for about 2 weeks. Now that I've fixed some of the major noise producers, whistling T-Tops etc, I've noticed there is a "roaring" noise (It's not a grinding or whining) coming from the read end of the car. It begins at about 20-30 mph. I can't tell if it's coming from one side or the other or center. I don't think it's the tires as the sound persists no matter the road surface, asphalt, concrete etc. Is this normal or a sign of a bad wheel bearing or differential gears?
Also, I measured from the wheel wells to the ground and the left side of the car sits about 3 " lower than the right. The previous owner was quite heavy so I was thinking sagging spring. The spring is however fiberglass and I didn't think they were supposed to fatigue. What gives? Please help.
Also, I measured from the wheel wells to the ground and the left side of the car sits about 3 " lower than the right. The previous owner was quite heavy so I was thinking sagging spring. The spring is however fiberglass and I didn't think they were supposed to fatigue. What gives? Please help.
Pro
Joined: Dec 2002
Posts: 560
Likes: 1
From: Mooresville NC
Sounds to me like it might be a bearing problem. Which bearing, hard to tell from here. I would remove the rear wheels and disconnect the half shafts. Spin each side and listen/feel for any vibrations this would isolate the trailing arm bearings. If everything is good there then look toward the rear differential, check fluid level. If the noise grumbling noise is coming from the differential, I don't think its normal. You may have to have it rebuilt.
Good Luck
Good Luck
Premium Supporting Vendor
Joined: May 2000
Posts: 4,312
Likes: 70
From: Clearwater FL
Which wheel wells did you measure? Front or rear.
Instead of taking the wheel off, jack the car up and grab the wheel at 12 & 6. Have someone push back and forth while you crawl under and look at the side yokes in the rear end. See how much play you have. If it's more than a 1/16th to an 1/8th inch in and out, your side yokes are going bad but I doubt that is whats giving you your roar. I think it would be the rear end itself. You can check your bearing assemblies by pushing at 3 & 9. You should have little to no play at all on those.
Instead of taking the wheel off, jack the car up and grab the wheel at 12 & 6. Have someone push back and forth while you crawl under and look at the side yokes in the rear end. See how much play you have. If it's more than a 1/16th to an 1/8th inch in and out, your side yokes are going bad but I doubt that is whats giving you your roar. I think it would be the rear end itself. You can check your bearing assemblies by pushing at 3 & 9. You should have little to no play at all on those.
Thread Starter
Burning Brakes
Joined: Jun 2004
Posts: 1,012
Likes: 5
From: Granbury, TX
Thanks guys. I measured from the ground to the top of the rear wheel wells.
I had the Vette up on stands and did not have any play (looseness) in the wheels.
Best I can tell, roaring is coming from the center. Know any good, Gulp, diff. rebuilders?
I looked all over for the plug to check diff fluid. Where is it? Is it above and to the front of the 1/2 shafts or behind? Is it at all visible from underneath the car or do I have to feel for it? My shop manual does not have a good picture.
I may very well need fluid. PO was not on top of things, Ball joints were dry and steering box was way low on gear oil.
I had the Vette up on stands and did not have any play (looseness) in the wheels.
Best I can tell, roaring is coming from the center. Know any good, Gulp, diff. rebuilders?
I looked all over for the plug to check diff fluid. Where is it? Is it above and to the front of the 1/2 shafts or behind? Is it at all visible from underneath the car or do I have to feel for it? My shop manual does not have a good picture.
I may very well need fluid. PO was not on top of things, Ball joints were dry and steering box was way low on gear oil.
Team Owner
Joined: Mar 2002
Posts: 24,160
Likes: 78
Originally Posted by Clint's C3
Also, I measured from the wheel wells to the ground and the left side of the car sits about 3 " lower than the right. The previous owner was quite heavy so I was thinking sagging spring. The spring is however fiberglass and I didn't think they were supposed to fatigue. What gives? Please help.
Racer
Joined: Jul 2003
Posts: 455
Likes: 0
From: Buffalo New York
the differential plug on my 77 is on the passanger side and can be seen if you look in from the rear wheel well. It is just a bolt in the middle towards the bottom of the differential case. I don't know if this will help, but good luck.
Drifting
Joined: Nov 2002
Posts: 1,593
Likes: 0
From: Mobile AL
St. Jude Donor '05
Didja check to see if the exhaust pipe is touching the frame somwhere. A roaring noise above 20-30 mph that does not change does not sound mechanical. Rear end noise would change with speed.
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Thread Starter
Burning Brakes
Joined: Jun 2004
Posts: 1,012
Likes: 5
From: Granbury, TX
Originally Posted by 77BuffaloVet
the differential plug on my 77 is on the passanger side and can be seen if you look in from the rear wheel well. It is just a bolt in the middle towards the bottom of the differential case. I don't know if this will help, but good luck.
I promise I won't ask about the muffler bearings.
The roar does get louder with speed, but does not change with load conditions like most diff problems I've seen.
Pro
Joined: Dec 2002
Posts: 560
Likes: 1
From: Mooresville NC
On my '79, the plug is a square looking plug. I don't know how else to describe it. Pass. Side, on the side of the diff about halfway up. When you remove it, I think a 18MM socket will fit, on level ground the fluid should come up to the hole. It should not flow out, just be even with the bottom of the hole.
Racer
Joined: Jul 2004
Posts: 420
Likes: 1
From: Lapeer MI
1) I had a roaring noise come out of my rear end for a while too. I knen I shouldn't have had that second helping or...
2) I had a roaring noise come out of the rear end too but now I have side exhaust.
Sorry I had to capitalize.
2) I had a roaring noise come out of the rear end too but now I have side exhaust.
Sorry I had to capitalize.
Premium Supporting Vendor
Joined: May 2000
Posts: 4,312
Likes: 70
From: Clearwater FL
steering box was way low on gear oil
--------------------------------------
Steering boxes do not use gear oil. They use grease. It looks like oil b/c it sit so close to the headers that it liquifies the grease. You may need to rebuild your box and use a high temp grease.
Dan
--------------------------------------
Steering boxes do not use gear oil. They use grease. It looks like oil b/c it sit so close to the headers that it liquifies the grease. You may need to rebuild your box and use a high temp grease.
Dan
Instructor
Joined: Jan 2004
Posts: 152
Likes: 0
From: Wilmington nc
I had the same problem, it sounded like one of thosejacked up 4X4's with some 44s was riding at my back corner.
Mine would get louder with speed too. It was hard to tell what side of the car it was comming from, it just echoed around behind the seats. But I also noticed if I cut the wheel sharp (real sharp about 40 mph) to the left the noise would go away for the sec I was turning.
It ended up being the pass side rear wheel bearing.
Mine would get louder with speed too. It was hard to tell what side of the car it was comming from, it just echoed around behind the seats. But I also noticed if I cut the wheel sharp (real sharp about 40 mph) to the left the noise would go away for the sec I was turning.
It ended up being the pass side rear wheel bearing.
Thread Starter
Burning Brakes
Joined: Jun 2004
Posts: 1,012
Likes: 5
From: Granbury, TX
Thanks for all the advice. I took off the left rear wheel and there was the plug. I can describe the differential plug location as about 11 o’clock looking from the passenger side above and behind the 1/2 shaft. You can barely see it from the rear at about 2 o’clock. The plug on my ‘82 takes a Hex drive, same size as some GM front brake pins.
The inside of my rear tires were "cupped". I rotated them and put my smooth tires on the back. Now there is no roar.
or at least I can't hear it, sitting much closer to the rear tires than the front, essentially what would be driving from the back seat of most cars.
I'll let you know when I find the muffler bearings. LOL.
The inside of my rear tires were "cupped". I rotated them and put my smooth tires on the back. Now there is no roar.
or at least I can't hear it, sitting much closer to the rear tires than the front, essentially what would be driving from the back seat of most cars.I'll let you know when I find the muffler bearings. LOL.
