Help ?? changing differential fluid
Thread Starter
Burning Brakes
Joined: Oct 2010
Posts: 1,057
Likes: 253
From: US-ARMY 1974-1996 Retired ; Oklahoma, City ; Atlanta, Ga: Hephzibah, Ga
Help ?? changing differential fluid
I am getting ready to change my differential fluid with GM fluid part # 88862624. I’ve read on the forum you have to do 10 figures 8's after the fluid change. Once I changed the fluid I will have to drive about 5 miles before I can get to an area where I do the figure 8’s safely. Will driving that distance cause any damage to the differential? Thanks
Team Owner
Joined: Mar 2008
Posts: 21,502
Likes: 461
From: Southern Utah
Until you do the figure eights, you may still get any groaning noises that you have now, but no damage will be done. The procedure is recommended so that a customer doesn't pick up his car from the shop, drive out and find that the noises have not gone away...and then complain. 
Team Owner
Joined: Sep 2000
Posts: 24,992
Likes: 2,694
From: Far NW 'burbs of Chicago
St. Jude Donor '13
Also, suggest remove the Fill plug before removing the Drain plug.
There have been a few people who drained the diff and then discovered they couldn't remove the Fill plug to put the new stuff in.
There have been a few people who drained the diff and then discovered they couldn't remove the Fill plug to put the new stuff in.
Retired & lovin' it!
Joined: Mar 2005
Posts: 4,472
Likes: 546
From: Jackson NJ
So true, so true! You will also find that on the '05, it's a bit difficult to get a hex drive into the drain plug which is directly over the rear spring with very little clearance. (The diff case design change in later years solved this problem). So....you might want to be sure you have the right tool before you start the job. I found a 10mm hex wrench & cut down the short end to about 3/4" & then use a short section of steel pipe on the long end for leverage.
Race Director
Joined: Sep 2000
Posts: 11,132
Likes: 1,905
From: Missouri City, TX
So true, so true! You will also find that on the '05, it's a bit difficult to get a hex drive into the drain plug which is directly over the rear spring with very little clearance. (The diff case design change in later years solved this problem). So....you might want to be sure you have the right tool before you start the job. I found a 10mm hex wrench & cut down the short end to about 3/4" & then use a short section of steel pipe on the long end for leverage. Since the OP has a 2005 with the difficult to access drain plug, it has been reported here that having the rear weight of the vehicle on the rear tires will take the bow out of the composite spring and allow more clearance above it to access the drain plug. To do that would mean lowering the rear wheels onto ramps and using jack stands up front to support the rest of the car.
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