Rear differential clunking noise when turning only.

[jmontero146]

Seems my rear differential is making a clunking noise or pop whenever I spend a while driving and make a sharp turn. The rear left  wheel locks up.only on sharp turns.What can this be my mechanic said it could be a bad clutch.

Edited July 23, 2019 by jmontero146 (see edit history)

[eberhama]

Unless someone changed it, you should have a gov-lock style limited slip, not a clutch type. It's possible it's stuck in the "locked" position. If this was the case, it would chirp the inside tire turning either way, though. Maybe pop the wheel& rotor off and check for a locked up caliper or a grenaded parking brake assembly.

[someotherguy]

Someone may have changed the gear oil as regular maintenance.  If so, and they put "posi" additive in it, that could be the cause.  The Gov-Loc specifically does not require "posi" additive as it is not a posi unit.  This is a highly-debated topic in some areas so if needed I can look up the TSB from GM that explains it; there's literally no argument.  GM specifically states that use of those additives in the Gov-Loc can cause improper operation of the locker.

It takes regular gear oil, and in your SS's case that would be 75W-90 synthetic.  I'd start there - replace whatever is in it with the proper lube so you know that is correct; this will also give you a chance to look inside and get an overall feel of the condition of the differential.  Check the amount of crud attached to the magnet, sitting in the case, and feel the edges of your gears, etc.

Richard

Edited July 23, 2019 by someotherguy (see edit history)

[jmontero146]

On 7/23/2019 at 10:31 AM, someotherguy said:

Someone may have changed the gear oil as regular maintenance.  If so, and they put "posi" additive in it, that could be the cause.  The Gov-Loc specifically does not require "posi" additive as it is not a posi unit.  This is a highly-debated topic in some areas so if needed I can look up the TSB from GM that explains it; there's literally no argument.  GM specifically states that use of those additives in the Gov-Loc can cause improper operation of the locker.

It takes regular gear oil, and in your SS's case that would be 75W-90 synthetic.  I'd start there - replace whatever is in it with the proper lube so you know that is correct; this will also give you a chance to look inside and get an overall feel of the condition of the differential.  Check the amount of crud attached to the magnet, sitting in the case, and feel the edges of your gears, etc.

Richard

Well I took it in last Monday he changed the clutches on the rear differential we put 75w 90 fluid and the clunk went away but now the rear wheels seem to bind or lock a little bit when making slow speed turns. He said the transfer case might be the problem.