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DISCUSSION => Engine + Driveline => Topic started by: Petebee on February 02, 2008, 06:20:25 PM

Title: Lift Throttle Clunking from Rear
Post by: Petebee on February 02, 2008, 06:20:25 PM
I have a pronounced clunk that occurs from what sounds like the rear of the car whenever I abruptly lift the throttle in a lower gear and get the car to jerk (kinda like a bad driver). I also noticed that if I engage the clutch immediately after hearing this and quickly move the shifter back and forth from first to second gear it sounds and feels a bit clunky, too. After moving the shifter back and forth about four times it stops making the noise/feeling and shifts smoothly.

Any ideas? I thought this may be a CV axle, and I replaced the passenger's side due to axial play in the shaft (approx. 1/8 - 3/16 inch of play if you pushed the axle back and forth from the diff to the rear hub). This amount of play seemed to be excessive. The driver's side has a slight amount, but not nearly like the passenger's did. I replaced the worn axle without drama.

My guesses (I am new to these cars) are:

- Worn rear subframe mounts (yuck)
- Something wrong with the driveshaft (yuck)
- Something wrong with the differential (yuck)
- Worn bushings in the trailing arms, diff and/or upper shock mount (not bad)

What do the gurus here think? I am kind of bummed as I know that I need to spend at least $500 to fix the worn timing components and I'd like to replace the OE suspension so that I can autocross this car. Sigh...

Car is 318i with factory LSD
Title: Lift Throttle Clunking from Rear
Post by: mdiddy on February 02, 2008, 08:04:37 PM
could be bad diff mount bushing..or in my case, gear lash in the diff. the open diff i had before did the same thing..
Title: Lift Throttle Clunking from Rear
Post by: Petebee on February 02, 2008, 08:12:10 PM
Quote from: mdiddy;42114
could be bad diff mount bushing..or in my case, gear lash in the diff. the open diff i had before did the same thing..


Hey are you around tomorrow (Sunday)? Maybe you can listen/feel for yourself.
Title: Lift Throttle Clunking from Rear
Post by: mdiddy on February 02, 2008, 08:21:26 PM
yeah, thats fine. i'll be around all day. give me a call
Title: Lift Throttle Clunking from Rear
Post by: Petebee on February 02, 2008, 08:46:49 PM
Will do. Thx.