Grinding/rubbing noise
Thread Starter
Melting Slicks
Joined: Feb 2001
Posts: 2,115
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From: VA
Grinding/rubbing noise
I have a low grinding/rubbing noise that sounds like it is coming from either the drive shaft or one of the half shafts. The sound doesn't happen all of the time. I usually hear it after I have driven the car for 30 min or more. I really notice it when I take it out for a good run on some country roads where I can open it up on the straight stretches and I have to brake a lot for the curves. I am guessing at the source of the noise. Any ideas what may be making the noise?
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
Re: Grinding/rubbing noise (Ron 75 L48)
Common symptoms for rear clutches. The 75-79s also have a problem with rear shaft wear which contributes to the clutch problems. Check the rear closely for shaft recession, and change the fluid and additive.
Racer
Joined: Sep 1999
Posts: 336
Likes: 0
From: Scott AFB IL
Re: Grinding/rubbing noise (wombvette)
I agree with wombvette, had same problems (almost), and changed rear end fluid.. Go to the GM dealer and spend the $$ for the right stuff (posi fluid) as its different from wal-mart stuff... THere is no plate on the rear end, take out the plug and use a suction device (i.e. drill pump) with a clear tube to get the old fluid out. Make sure to tilt the vehicle left side up and right side up to get the fluid out of the axle housings (not a lot of fluid in the cavities, but enough).. I think I had to buy 3 bottles of juice and used 2.1...
good luck.
good luck.
Melting Slicks
Joined: Oct 2000
Posts: 3,023
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From: TEXASTEXASTEXASTEXAS TEXASTEXASTEXASTEXAS
St. Jude Contributor
Re: Grinding/rubbing noise (wombvette)
Wombvette's right on. I had a very similar conditions--kind of a groaning/rubbing noise after a run of more than 20 minutes at highway speeds, sounded worst when turning. Changed out the fluid in the pumpkin, put in two bottles of GM posi-lube additive, did some figure eights in a parking lot. Next long run there was no noise. Big relief, because the guys here had suggested it might be something more serious in the differential if the fluid change didn't help.
JB
'78SA
JB
'78SA
Advanced
Joined: Apr 2000
Posts: 90
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From: Hobart, Tasmania, Australia
Re: Grinding/rubbing noise (Ron 75 L48)
At the risk of sounding repetitive, drain and replace your diff fluid!
I was a skeptic when I had exactly the same symptons, started doing the sums for a new diff...... :rolleyes: :mad
Replaced the diff oil and voila! No more chattering/grinding..
IT WILL WORK! :D
I was a skeptic when I had exactly the same symptons, started doing the sums for a new diff...... :rolleyes: :mad
Replaced the diff oil and voila! No more chattering/grinding..
IT WILL WORK! :D
Thread Starter
Melting Slicks
Joined: Feb 2001
Posts: 2,115
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From: VA
Re: Grinding/rubbing noise (Ron 75 L48)
Thanks for all of the responses. Of course I was assuming all of the worst case senerios and all of the $$$ I am going to have to spend on this! I see about getting the differential fluid changed out this weekend and hopefully that will take care of my problem. Again thanks! :cheers:
