Topic: Help! replacing Diff. Mount rubber
in Forum: C3 Driveline Components
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This is for an '81..
I started out this morning to replace my shocks and the rubber pucks that go between the frame and the front mount of the differential. Hours later, haven't gotten the old puck out yet. The problem seems to have interrelated reasons:
1) I can't pry the front of the differential down more than maybe 1/2", as the diff. yoke will eventually hit the frame.
2) Just in front of the cast-in "tab" in the differential, where the front mount is, the frame angles down very sharply, so it looks like I would have to pry the front of the differential down 1" to maybe 1-1/2" to get the puck out. (note, I believe the earlier Vettes used a steel bracket bolted onto the differential and the front mount/puck rode on this bracket, so you could just loosen the bracket to do this job. Not the case w/ the '81. Instead of a bolt-on bracket, the differential has a big "tab" cast into it in the front and the mount/puck mounts directly to that.
I did remove the driveshaft to get more room for this operation. Also, when I was having little success, I also unbolted the two mounts where the differential crossmember mounts to the frame. This allowed the back-end of the differential to drop a couple of inches before the trailing arms bottomed out. This helped out the tension on the front mount, but I still can't pry the front down enough because of the problems mentioned above.
Any ideas? I'm starting to think that the only way to do this job on an '81 is to drop the rear-end completely. What a pain!
Thanks!
I started out this morning to replace my shocks and the rubber pucks that go between the frame and the front mount of the differential. Hours later, haven't gotten the old puck out yet. The problem seems to have interrelated reasons:
1) I can't pry the front of the differential down more than maybe 1/2", as the diff. yoke will eventually hit the frame.
2) Just in front of the cast-in "tab" in the differential, where the front mount is, the frame angles down very sharply, so it looks like I would have to pry the front of the differential down 1" to maybe 1-1/2" to get the puck out. (note, I believe the earlier Vettes used a steel bracket bolted onto the differential and the front mount/puck rode on this bracket, so you could just loosen the bracket to do this job. Not the case w/ the '81. Instead of a bolt-on bracket, the differential has a big "tab" cast into it in the front and the mount/puck mounts directly to that.
I did remove the driveshaft to get more room for this operation. Also, when I was having little success, I also unbolted the two mounts where the differential crossmember mounts to the frame. This allowed the back-end of the differential to drop a couple of inches before the trailing arms bottomed out. This helped out the tension on the front mount, but I still can't pry the front down enough because of the problems mentioned above.
Any ideas? I'm starting to think that the only way to do this job on an '81 is to drop the rear-end completely. What a pain!
Thanks!
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Are you sure the trailing arms are bottoming, or is it the shocks holding the rear up? I would suggest un-bolting the shocks at the top, and let the diff down a bit more.
I would have thought that just removing the two side bolts on the "bat-wing" would have let the diff down enough to get the puck out of there. You ought to be able to get the diff Bat-wing completely out of the frame brackets, and then slide it rearward far enough to get the mount out. Take the shocks loose, and see what you get.
Another idea is to take one of the half-shafts loose from the diff. This will let it come down. It appears that you have too much tension on the half-shafts to allow the diff itself to drop. In reality, taking the front bolt out where the puck is, and the two bolts out of the side frame brackets would basically have the diff completely out of the car, except for the half-shafts, the spring mount, and the camber control rods.Adams' Apple 2007-04-01 18:42:21
I would have thought that just removing the two side bolts on the "bat-wing" would have let the diff down enough to get the puck out of there. You ought to be able to get the diff Bat-wing completely out of the frame brackets, and then slide it rearward far enough to get the mount out. Take the shocks loose, and see what you get.

Another idea is to take one of the half-shafts loose from the diff. This will let it come down. It appears that you have too much tension on the half-shafts to allow the diff itself to drop. In reality, taking the front bolt out where the puck is, and the two bolts out of the side frame brackets would basically have the diff completely out of the car, except for the half-shafts, the spring mount, and the camber control rods.
Joel Adams
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in Forum: C3 Driveline Components
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