Exhaust Rattle after replacing Transmission Mount

So yesterday I replaced my Engine and Transmission mounts, and when I pulled the cross member for the transmission there was a odd circular rubber deteriorating piece of rubber between the square exhaust mount thing and the plate.

http://s702.photobucket.com/user/meanmax/media/Transmission/P1010581.jpg.html (This Mount, not my jeep)

I discarded this piece or rubber as it was worn out and I didn't really understand what it was there for. After all the new mounts were installed and everything back together I drove around the block and noticed knocking when I accelerated. It was too late to continue to mess with it, so I just drove it home as is. I'm assuming this chunk of rubber was somehow supporting the exhaust mount, and now without it there is more play in the pipe and somewhere it is rattling against something.

I looked online and I can't find this rubber part, so I'm guessing it was just a makeshift fix the PO did. So I'm guessing I should just rind another piece of rubber to wedge back in there?

1990 Renix Cherokee Limited 4.0 AW4 242

There should have been a hanger, looks like a long finger, welded to the exhaust pipe that slips into a rubber grommet on your cross member. The bracket for that shares the same bolt as your transmission mount.

Be aware there are a couple of different designs for that piece of rubber. When I installed the Borla header in my '96 I had to change from the round bar support rod to the half moon shape. Here are some pics to help with what I mean:



I needed to switch from that above to this below:



I was able to get the correct piece of rubber from Morris 4x4. If I recall correctly it was a Crown part. Replacing it required drilling out the factory rivets, using a cold chisel to separate the steel bracket parts (they really press those rivets in there), swapping the rubber pieces and then putting it back together with 10-32 screws and nuts.









Hopefully we are talking about the same thing and that makes it clear for you.

Interesting, yeah I think the rubber was just a cut piece of radiator hose inserted there to tighten up that mount. After my engine cooled down today I notices that there is a little play at that point, and the tail pile where it bends over the rear axle had enough play to bounce up about a centimeter and hit the frame near the rear tire. The PO cut the exhaust just past that last bend so I don't think there was enough weight to keep it from bouncing.

I ended up just putting a large hose clamp around that diamond shaped rubber hanger thing that is near the rear axle. This forces the exhaust pipe up against the frame where it was hitting it and kept it from rattling. I assume this probably isn't the best fix, but will this have an adverse effect on the exhaust, will it transfer more vibrations into the cat / muffler or cause a leak or something? I assume they isolate the exhaust with rubber for a reason.

You need flexibility in your exhaust system. You'll crack your exhaust manifold and the heat from it'll get the floors way hot.

Anak
Yes, that's what I am talking about. Thanks for the more in depth explanation.

Rock Auto sell the square rubber bushing for the exhaust hanger.
Look up DEA A5208

Are you sure you didnt install the crossmember backwards. I had a similar problem and that was my issue. Crossmember has a cutout for the exhaust pipe so if installed backwards it will rattle.

This is what i did... first jeep ive ever owned sans exhaust rattle... this is after a the flex joint

I just vice-gripped the half-moon into a circle to make the Borla fit in my '96.