e36 rear noise and annoying wobble

[e36conv]

My e36 94 conv making a thumping sound from underneath the shifter console after start up . I notice the car will idle rough for maybe 30 second to a minute ,and then its fine. While its having the dramatic rough idle. If I hit the gas a little I can hear a thump, sounding like something hitting from outside the tranny tunnel vibrating the center console. After I hit the gas couple times the thumping goes away, but I can still hear a rattle sort of sounds like a exhaust heat shield flexing . My other problem is a crazy roar from the rear . I think its a rear wheel bearing getting bad dued to the wobbling feeling of my rear tire at low speed. I have had two final thoughts about it . It can be a wheel bearing or a center carrie bearing ,but theres no actual evident yet . Has any loyal e36 owner have had this problem ? Please help Im going crazy this is my 4th e36 and never had this problem.

[bostogrun]

How many miles are on your car? Its really important when dealing with these issues.

The wheel bearing will not make car wobble but it will roar almost like a loud exahust. You need to have someone sit in the backseat while you drive and try to figure out which side is the bad one. Its a little job to do the rear wheel bearing on these cars. You could also have a bad upper shock mount that would make car meander because the rear axle is not fastened to the car anymore. This was more of a problem on the e30s but its possible on e36s. I am sure but perhaps convertible chassis are more prone to this problem. The chassis unibody material actually cracks and breaks where the shock bolts to the frame. There is a place on the internet somewhere that sells a patch thing that welds over the ruined part.

In regard to the drive shaft thumping did you check the "guibo" flex coupling a kind of "u joint"that resembles a large hockey puck between the tranny output and the rest of the drive line with mileage these things start to shred and give a thump when you shift into gear because you are taking up the slack due to wear. That would explain the thumping in the tranny tunnel. This doesn't have anyting to do with a rough idle (do you have a code?) a rough idle could be the result of a dozen things including a vacume leak, bad idle control value, failures in the fuel delivery system.

My guess is you have a worn guibo and a broken shock or shock mount.