Differential "chattering" noise.
Thread Starter
Safety Car
Joined: Oct 2007
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From: Pennsylvania
Differential "chattering" noise.
I just replaced the differential oil in my 85 4+3 with 80W90 GL5 (1.4 quarts) and 4 oz. of AC Delco additive for the limited slip differential. I did this because the differential was getting a light chattering noise at very low speed from a stop, and going around a tight bend slowly. Right after the change I noticed that the light chattering is still there but goes away after about 15mph as before. Does it take awhile for the AC Delco LSD additive to quiet this down, or do you think I shouild add another 4oz. of additive? Everything in the driveline seems to be fine.
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I just replaced the differential oil in my 85 4+3 with 80W90 GL5 (1.4 quarts) and 4 oz. of AC Delco additive for the limited slip differential. I did this because the differential was getting a light chattering noise at very low speed from a stop, and going around a tight bend slowly. Right after the change I noticed that the light chattering is still there but goes away after about 15mph as before. Does it take awhile for the AC Delco LSD additive to quiet this down, or do you think I shouild add another 4oz. of additive? Everything in the driveline seems to be fine.
Thread Starter
Safety Car
Joined: Oct 2007
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From: Pennsylvania
A little side note. The car currently only has 51,000 miles and always been well taken care of and maintained. Never beat in other words. At highway speeds there is absolutely no whine or strange noises. The chattering does not always occur. It only seems to be sporadic at very low speed.
Thread Starter
Safety Car
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From: Pennsylvania
It's more of a metalic clicking noise at low speed. The gear oil that was removed was fairly clean. No metal fragments in it.
Last edited by FOURSPEEDVETTE; Sep 19, 2017 at 05:15 PM. Reason: Typo
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I had an 88 years ago that I put GL5 lube in the rear diff. It squealed during turns at low speeds. I added the GM additive, and it made no difference. Still squealed. I sucked the GL5 lube out with a suction pump and refilled with GM's diff oil, and another 4oz of the additive. Noise was gone.
I don't remember the source, but I recall reading that GL5 is not compatible with preloaded friction posi differentials like the Dana's use. It has to be GL3 or GL4, with the additive.
I don't remember the source, but I recall reading that GL5 is not compatible with preloaded friction posi differentials like the Dana's use. It has to be GL3 or GL4, with the additive.
A quick check of Dana usage in FOMOCO and MOPAR the specification is always GL5 with a note to add "modifier". The "paper guide" I use is from Castrol and 10 years old but I relied on it heavily and not the web-based guides.
GL4 and GL5 gets debated more frequently when discussing older manual transmission because of syncronizer ring materials.
Last edited by WVZR-1; Sep 20, 2017 at 09:12 AM.
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Don't be afraid to double up on the LSD fluid additive.
Some of the dino oils need an extra shot to loosen the oil.
Also run the car in a slow tight circle for a few revolutions in both directions to get lube between the plates.
Some of the dino oils need an extra shot to loosen the oil.
Also run the car in a slow tight circle for a few revolutions in both directions to get lube between the plates.
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Thread Starter
Safety Car
Joined: Oct 2007
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From: Pennsylvania
Well...... So far I wasted $500.00 trying to eliminate this "metalic" popping or snapping noise in my left rear wheel area at very slow speed! 
I replaced the 80W90GL5 gear oil and 4oz. Delco additive first in the differential. No improvement. Today I had a mechanic tell me he fixed it. He replaced the inner and outer half shaft U-joints. The noise is still there! He didn't fix it! He said he couldn't find anything wrong with the wheel assembly. There is no wobbling, vibrating, or humming noise in the rear end. I had this same snapping/popping noise in a previous car I had and it only needed LSD additive put in. Noise disappeared right away. Should I drain 4oz. of gear oil out and add 4 more oz. of AC Delco LSD additive? This is getting expensive!
I replaced the 80W90GL5 gear oil and 4oz. Delco additive first in the differential. No improvement. Today I had a mechanic tell me he fixed it. He replaced the inner and outer half shaft U-joints. The noise is still there! He didn't fix it! He said he couldn't find anything wrong with the wheel assembly. There is no wobbling, vibrating, or humming noise in the rear end. I had this same snapping/popping noise in a previous car I had and it only needed LSD additive put in. Noise disappeared right away. Should I drain 4oz. of gear oil out and add 4 more oz. of AC Delco LSD additive? This is getting expensive!
Last edited by FOURSPEEDVETTE; Sep 25, 2017 at 06:41 PM.
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Well...... So far I wasted $500.00 trying to eliminate this "metalic" popping or snapping noise in my left rear wheel area at very slow speed! I replaced the 80W90GL5 gear oil and 4oz. Delco additive first in the differential. No improvement. Today I had a mechanic tell me he fixed it. He replaced the inner and outer half shaft U-joints. The noise is still there! He didn't fix it! He said he couldn't find anything wrong with the wheel assembly. There is no wobbling, vibrating, or humming noise in the rear end. I had this same snapping/popping noise in a previous car I had and it only needed LSD additive put in. Noise disappeared right away. Should I drain 4oz. of gear oil out and add 4 more oz. of AC Delco LSD additive? This is getting expensive!
I replaced the 80W90GL5 gear oil and 4oz. Delco additive first in the differential. No improvement. Today I had a mechanic tell me he fixed it. He replaced the inner and outer half shaft U-joints. The noise is still there! He didn't fix it! He said he couldn't find anything wrong with the wheel assembly. There is no wobbling, vibrating, or humming noise in the rear end. I had this same snapping/popping noise in a previous car I had and it only needed LSD additive put in. Noise disappeared right away. Should I drain 4oz. of gear oil out and add 4 more oz. of AC Delco LSD additive? This is getting expensive!https://www.corvetteforum.com/forums...post1591070166
I'd think you could check excessive pinion/side gear in the carrier by quick twists of the wheel forward backward with the pinion locked in place. You could certainly see if you can easily recreate what you say you hear.
Drifting
Joined: Mar 2013
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From: Venice Cali.
I used 2 bottles(no probs) when I changed oil in the D36. But I also changed wheel bearings and ujoints also. put the car up and check 3-9,12-6 and calipers,pads(bend the springs out more), bushings ect. My long looked for clunk(6months) turned out to be loose shock mount(lower). Before that I had 2 rear shocks worn out and making klunking. I only found out by driving thru the alley without the rear shocks. Good luck investigating
Last edited by xrav22; Sep 30, 2017 at 11:01 PM.
Team Owner
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I used 2 bottles when I changed oil in the D36. But I also changed wheel bearings and ujoints also. put the car up and check 3-9,12-6 and calipers,pads(bend the springs out more), bushings ect. My long looked for clunk(6months) turned out to be loose shock mount(lower). Before that I had 2 rear shocks worn out and making klunking. I only found out by driving thru the alley without the rear shocks. Good luck investigating
Le Mans Master
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I can't speak to the diff oil you use ... but don't think that it hurts anything at all to run two bottles of the additive. I always have to mine and I was putting 15K a year on the car for 6 years as my year round dd.
Full disclosure when I bought the car with 30K I changed the diff as well as oil & trans over to amsoil. but when I took the long slow sharp right turn into our driveway the right rear tire seemed to be chirping (don't know if that's the same as a chatter) . Pull a little bit out added a 2nd bottle and the chatter went away. Have run it this way over the past 100k I've put on the car and changed the diff fluid after about 70K and did it again with 2 and I've never had a problem. probably overkill.
Full disclosure when I bought the car with 30K I changed the diff as well as oil & trans over to amsoil. but when I took the long slow sharp right turn into our driveway the right rear tire seemed to be chirping (don't know if that's the same as a chatter) . Pull a little bit out added a 2nd bottle and the chatter went away. Have run it this way over the past 100k I've put on the car and changed the diff fluid after about 70K and did it again with 2 and I've never had a problem. probably overkill.
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I had an 88 years ago that I put GL5 lube in the rear diff. It squealed during turns at low speeds. I added the GM additive, and it made no difference. Still squealed. I sucked the GL5 lube out with a suction pump and refilled with GM's diff oil, and another 4oz of the additive. Noise was gone.
I don't remember the source, but I recall reading that GL5 is not compatible with preloaded friction posi differentials like the Dana's use. It has to be GL3 or GL4, with the additive.
Usually posi problems from incorrect lube results in jerking at low speeds during cornering, but usually doesn't produce any noise. A "clicking" from the rear, especially on take-off in a straight line can be the rear axle splines within the rear hub. Even with the nut tight. There is a GM derelin washer available to cure this noise. I'm sure there are threads on here that mention this washer and noise. First I'd get rid of the GL5, and then evaluate any noise or clicks.
Happy hunting.
I don't remember the source, but I recall reading that GL5 is not compatible with preloaded friction posi differentials like the Dana's use. It has to be GL3 or GL4, with the additive.
Usually posi problems from incorrect lube results in jerking at low speeds during cornering, but usually doesn't produce any noise. A "clicking" from the rear, especially on take-off in a straight line can be the rear axle splines within the rear hub. Even with the nut tight. There is a GM derelin washer available to cure this noise. I'm sure there are threads on here that mention this washer and noise. First I'd get rid of the GL5, and then evaluate any noise or clicks.
Happy hunting.
Thread Starter
Safety Car
Joined: Oct 2007
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From: Pennsylvania
I added a second bottle of AC Delco LSD additive to the differential and the clicking noise is gone! I also contacted the mechanic's shop owner about them charging me all that money, (almost $500.00) for nothing! I got most of my money back! I only paid $65.00 for the "U" joints. Even though there was nothing wrong with the old ones, I have new ones with grease fittings in them now.
Last edited by FOURSPEEDVETTE; Sep 30, 2017 at 10:52 PM.