Thud when changin gear

[bmw325ise]

Hi Guys,

Hi have what seems to be the infamous thud noise when changing into 1st , 2nd and reverse. The loud thud comes from the rear of the car.

I have read many posts on forums on the internet that suggest the following:

1) Guibo, Flex Disc or Prop shaft Coupling or whatever you want to call it maybe worn, in my case it was worn, I had it replaced, still the noise persists.
2) Others have suggested to change the transmission fluid, I have done this as well and the noise is still there.
3) One of the most drastic outcomes of this maybe the fact that the rear sub frame has been ripped away from the car… I checked this, had a stealer check this and we both came to the same conclusion, nothing wrong with the sub frame.
4) I have also changed the Differential fluid.

Does anybody know what this actually could be? I have tested and checked all of obvious and now beginning to run out of ideas, I’m sure this is affecting the performance of the car.

If I hold my foot on the clutch for say 5-10 seconds before engaging the gears, all is well, no thud, this suggests to me a clutch issue, but I am no mechanic. I’m looking to the pro’s of this forum to give me some help, any help would be much appreciated.

Thank-you

Andy

BMW 325i SE 1991 (E36)

[bad man working]

Check all the mounts engine, gearbox, diff, suspension and the centre diff I’ve never heard a clutch knock

[bitcore]

I believe new tranny mounts could help, probably wont cure it but the thud is due to slack in the driveline and the tranny mounts are notorious for being weakend and allowing the transmission to twist under load. (which = a money shift if you shift and the transmission is still torquin)
My rear subframe is loose, but not torn. Since I have an automatic with a weak engine, and a late model chassis it's not so much of a concern with me, but eventually it will wiggle itself to pieces.


Put the E-brake on HAAARD, chock the wheels like a motherfucker, and get someone you trust with your life to put the car in a gear that it makes the thud (preferably 1st gear!) and feather the clutch or whatever you do that makes it thud. You go behind it and look under the car and watch the rear driveline when the friend puts it in gear.
Better yet would be to get a webcam, some USB extension cables, and duct tape a webcam under the rear of the car, looking at the subframe. Be sure to use software that RECORDS so you arn't driving around watchin it! This is what I did and mine rotates a whole lot up and down (on the axis of the rear wheels instead of the driveaxle) according to the torque being applied to it... That disturbed the shit out of me but I can't see anything BROKEN about it other than the bushings are worn to hell or some bolt is loose.....

I should post some videos.

[SpeedInfusion]

bitcore ur subframe is lose? is that fixable, i hear crazy thumping sounds from my rear latley, check diff bolt, wasnt it, im afraid of it being the subframe, i hope i can still add the reenforcements before its too late...

[bitcore]

Something back there is loose as hell... I know it.

[97alpineM3]

Have you checked the jack next to the spare?... or the battery?

Les

[SpeedInfusion]

bitcore have ur frame checked out...