Hey Chris,

Here is my definition of the noise in the rear:
Crossmember mount bushing/insulators have gone bad
- A clunk comes from the rear sounding almost like the tire is hitting the fender well. The clunk can upon shifting or even going over bumps when it starts really getting bad.

Here is a diagram:
Lets all get on the same page...go to the top of the zboard and click on what's new. At the new page click on 'abc order', then scroll down to the images directory and click on it. Then find and click on rearexp.gif. Once this image comes up...print it! You can also go directly there by http://eb-p5.uah.edu/~morgan/z/images/rearexp.gif

Firstly, check the crossmember mount insulator/bushings (xmem bush) the correct way. Take a floor jack and jack up the xmem in the middle (where the differential mounts, this will hold xmem in place so it will not kick out and hurt you when you remove member stays). Remember to choke the front wheels in front and behind and put jack stands under the rails to be safe. Remove the member stays to get a look at the xmem bushes. The bushings have a metal sleeve thru the middle. The metal sleeve should be firmly connected to the rubber bushing and the rubber should not be cracked or separated (on mine the metal sleeve in the center almost fell out when I took off the member stay). If you can't see anything visually wrong try taking the butt of a screwdriver and a rubber mallet and tap around on the metal sleeve. If it is springy and you still can't see any separation of the rubber you might want to check other possible reasons for clunking (differential mount insulator or shock bumper).

Prior to xmem bush replacement:
Spray every nut and bolt you can find with penetrant the day befor.

To replace the xmem bush:
Place chokes in front and behind the front wheels. Release the emergency brake. Loosen the rear wheel lug nuts. Jack up the rear of the car. Support under the rails with jack stands. Remove the rear wheels. Slightly jack up the suspension arms approx. 1-2". Jack up arms under the shock. You only want to remove the weight of the suspension arms. Better to leave a little weight on the arms than to compress the spring and shock. Under compression, the arm would kick down into you, the exhaust or the driveshaft. Under the weight of the arms, it would kick the opposite way..into the bottom of the car. I'm just saying this so you will be alert to the potential for injury here. It's pretty simple..just jack it up a little and remove the weight. Support the suspension arms with jack stands at the 'Y' (the arm is connected to xmem in two places, support where these two meet). Take a concrete block and place it under the differential where it mounts to the xmem. Use a scissor jack (block is cuz scissor jack will not
reach from the ground) and slightly jack up the differential (again, only remove the weight). ---PHASE ONE COMPLETE, now we can begin to remove xmem---- Remove the stabilizer bar. Keep track of bushings and the way they went together. Remove the emergency brake cable at the 'Y'. One cable comes from the front of the car and right before the xmem it 'Ys' to each rear tire going thru the xmem. Just remove the spring attaching to the cable and the xmem. Screw off the adjustment piece. Remove the retaining clips on the xmem and feed the cables thru the xmem. Pull the cables out of the way. Use a scratch marking tool and mark the relation of the suspension arm bolts to the xmem. The bolt heads have marks on them, mark where they sit in relation to the xmem. The inside bolt is especially important as it adjusts your toe-in. Use a floor jack and remove the jack stand under the suspension arm, making sure to adjust the floor jack back to the same place as before. Remove the suspension arm bolts. You can tell if the
suspension arm is loaded. The nuts, after breaking the initial torque, will screw right off the bolts. If the bolts don't pull out fairly easily, then the suspension arm might be loaded. Just be careful. I had no experience doing this and it was fairly easy. Swing the arms out from the xmem and re-support at the 'Y' with the jack stand. Remove the other suspension arm following the same procedure. Remove the three bolts holding on the member stays. Remove the four bolts attaching the differential. The four bolts attached to the differential have nuts on the top. You can lower the scissor jack to give you more room on top. -----PHASE TWO COMPLETE, you can now remove the xmem---- If the xmem has not already fall off. Remove the scissor jack and carefully pull off the xmem. With the xmem off, inspect the underside of the car and the xmem for any rust (just something I always do when I remove something that hasn't been off in 12yrs). Repair rust if any. Mine had none. Take a scratch marker and mark the position
of the existing bushing in relation to the xmem. You will want to replace the new ones in roughly this same position (not to critical, but get it as close as possible when replacing). Take a hammer and beat out the metal sleeves on the old xmem bushings. Take a hack saw and cut thru the remaining rubber and the thin metal outer sleeves. Remove the old xmem bushings (I took a chisel and hammer and bent back the corners of the cuts and it pulled right out). Clean up the xmem bush holes with sand paper if needed (I didn't). This is where I cheated a little. I threw the xmem in the back of my wife's car, took it to the local dealership and slipped one of the mechanics $20 to press in the new ones. Took all of 5 minutes for them to press in on a hydralic press. If you don't have access to a hydralic press, take the xmem to a local mechanic to press in. Obviously, you will need to set this up in advance. Make sure the new bushings go in reasonably close to the same position as the old ones.----PHASE THREE COMPLETE, new xmem bushings in place----- Take the xmem and position it under the car. Place a concrete block near one side. Set one end on the concrete block and lift up the other side. Replace the xmem bush cap, put the xmem on the bolt and put on one nut loosely. Go over to the other side and do the same. Re-position the concrete block and the scissor jack under the differential. Now re-attach the differential to the xmem. This takes a little playing with. Try raising or lowering the differential with the scissor jack till the holes line up. Loosely put on the nuts till you have all four bolts back in place. Torque to the correct setting (I believe 72 to 87 Ft-lbs). Remove the loosenly threaded nut on the xmem bush thru bolt. Re-position the member stay and replace the three bolts (torque 58 to 80). Use a floor jack and remove the support under the suspension arm. Re-position the suspension arm. This was tough until I lowered the floor jack. Once you get it at the right height (wish I could be more specific here,
but it is lower than equalibrium. I let some weight on them and I could manipulate the arms pretty easy). This had to be the hardest part. The arms are really tough to move around with the spring/shocks/rotors all coming into play. It was shifting all around, the arm ends diving when I jacked up and then pointing up to high when I let the jack down. When I did find that right position though, I rolled the floor jack forward, the holes matched up and I slide the bolts right thru. Match the marks on the suspension arm bolt to the scratch you made before and torque down the nut (72 to 87). Pull the emergency brake cables back thru the xmem. Re-attach the retaining clips. Re-attach the adjustment piece (the emergency brake should click 8 to 10, if not get back under and re-adjust later). Re-attach the spring holding the 'Y' to the xmem. Re-position the stabilizer bar. Attach to the xmem (torque 23 to 31). Re-attach the stabilizer bar bushings in the correct order and positon (torque 12 to 15). Replace the rear
wheels. Lower car and torque rear wheel lugs 58 to 72. Remove front wheel chokes.

----YOU HAVE NOW COMPLETED THE CROSSMEMBER MOUNT INSULATOR/BUSHING REPLACEMENT!!!!

I could not have replaced mine without the help of David Wimer and Elson 2+2. I give full credit of this post to those two guys. I'm just glad to pass it on!! Thanks David and Elson!!

Hope this helps

JB