lt rear noise
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Instructor
Joined: Apr 2007
Posts: 143
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From: Huntington Beach ca
lt rear noise
If I'm stopped and turn right while gasing it I get a clunking noise. Ive changed the u-joints on both half shafts. It doesn't seem to do it all the time. Almost seems like its in the differental. Anyone have any ideas? Sorry foregot to say it's an 88 vette
Last edited by jameskarate; May 8, 2009 at 08:12 PM.
Melting Slicks
Joined: Nov 2008
Posts: 2,765
Likes: 5
It might be time to change the rear axle- differential gear oil.
It may solve this clunking problem on right hand turns.
The posi-traction clutches within the diferrential with broken down gear oil will sometimes chatter on left or right hand turns.
You will need a small 5/16" inch diameter hose to pull the gear oil out of the differential plug and a fluid suction pump. Like the kind a mechanic would use in a shop. Or there are specialty aftermarket pumps you can buy also to do this job. Or borrow one from a freind.
Drive the car for a few miles to warm up the gear oil in the differential.
This makes it easier to pull/suck the thick 75-90W gear oil out.
Be sure to use a high quality gear oil. I prefer Royale Purple 75-90w Full synthetic Gear oil. Available at your local Speed Shop, Summit Racing, Sometimes Autozone or O'Reileys Stores in my area stocks it.
Also need to add a Positraction additive to the differential. I only Recomend the GM Positraction additive. It is available from Your local GM Dealership. Need 1 4ounce bottle of the stuff. About $8 bucks for it.
After removing the old gear oil. Add the GM positraction additive 1st to the differential.
Putting the additive in 1st makes sure You can get the entire 4 ounces in, have room for it and fill the rest with gear oil.
Then fill it with a high quality gear oil.
Then drive your Corvette for a few miles in town and the highway. If You can find a large empty and unobstructed parking lot. Make several slow speed Figure 8's in that parking lot (5-10mph). Takes about a 80 foot square parking lot to do this safely. Doing this works the fresh gear oil and GM positraction additive into the Positraction clutches of Your Dana 36 or Dana 44 Rear Diff. in your Vette.
Afterwards if all it was bad/worn out, Broken down gear oil in the Diff. It will be quiet again on any turns for many more years.
I had a similar problem on my 1987 Corvette Convertible when I bought it about 2 years ago. Changing out the old gear oil and refilling it with Royale Purple Synthetic Lube and GM Posi additive took care of my clunking and chattering in the rear diff. when mking left or right turns.
Try it and let me know if this works for You too or not.
Brian R. ASE Master Mechanic & Former GM Mechanic.
It may solve this clunking problem on right hand turns.
The posi-traction clutches within the diferrential with broken down gear oil will sometimes chatter on left or right hand turns.
You will need a small 5/16" inch diameter hose to pull the gear oil out of the differential plug and a fluid suction pump. Like the kind a mechanic would use in a shop. Or there are specialty aftermarket pumps you can buy also to do this job. Or borrow one from a freind.
Drive the car for a few miles to warm up the gear oil in the differential.
This makes it easier to pull/suck the thick 75-90W gear oil out.
Be sure to use a high quality gear oil. I prefer Royale Purple 75-90w Full synthetic Gear oil. Available at your local Speed Shop, Summit Racing, Sometimes Autozone or O'Reileys Stores in my area stocks it.
Also need to add a Positraction additive to the differential. I only Recomend the GM Positraction additive. It is available from Your local GM Dealership. Need 1 4ounce bottle of the stuff. About $8 bucks for it.
After removing the old gear oil. Add the GM positraction additive 1st to the differential.
Putting the additive in 1st makes sure You can get the entire 4 ounces in, have room for it and fill the rest with gear oil.
Then fill it with a high quality gear oil.
Then drive your Corvette for a few miles in town and the highway. If You can find a large empty and unobstructed parking lot. Make several slow speed Figure 8's in that parking lot (5-10mph). Takes about a 80 foot square parking lot to do this safely. Doing this works the fresh gear oil and GM positraction additive into the Positraction clutches of Your Dana 36 or Dana 44 Rear Diff. in your Vette.
Afterwards if all it was bad/worn out, Broken down gear oil in the Diff. It will be quiet again on any turns for many more years.
I had a similar problem on my 1987 Corvette Convertible when I bought it about 2 years ago. Changing out the old gear oil and refilling it with Royale Purple Synthetic Lube and GM Posi additive took care of my clunking and chattering in the rear diff. when mking left or right turns.
Try it and let me know if this works for You too or not.
Brian R. ASE Master Mechanic & Former GM Mechanic.
