Clunk / Thud When Downshifting

[AwakenNoMore]

Hmmm, interesting thread, my car does this too. Not a constant thing but it'll downshift too late or something like that. As long as it lasts until tax season I don't care. I pick up a G260 last week, just need the rest. Can't wait to be rid of this slushbox prison.

[myfirst325]

Same problem. Just started noticing the tranny thud while coming to a stop. Wasabi, did you drive it till the tranny died. How many miles after you started hearing the thud. I was hoping to make it to summer before the 5 speed swap.

[wasabinuki]

You can guess what the mystery clunk is, or have a pro who specializes in E30s give you the real deal. Probably not around the corner from you, but if your car can limp to Huntington, go see Robert at E30 motor werks. You're pretty much pissing in the wind with guesses otherwise.

http://www.e30motorwerks.com/

I am the one who started this thread, and if you look at the first post in the thread you will see what I replaced in my efforts to "fix" my clunk/thud. I've taken my car to Robert several times for installs and like him very much. I also took it to him to help me diagnose what was causing the thunk (to which he said my transmission was fine). I'm just saying that from my experience, and in my opinion, I'd bet that the transmission is the cause of the problem.

[lateracer]

You can guess what the mystery clunk is, or have a pro who specializes in E30s give you the real deal. Probably not around the corner from you, but if your car can limp to Huntington, go see Robert at E30 motor werks. You're pretty much pissing in the wind with guesses otherwise.

http://www.e30motorwerks.com/

[Etexise30]

when my buddies lsd was going out .it was nothing but pure clunks and thuds

[Etexise30]

check center support bearing,check u-joints and check diff fluid level,then do a diff test by rotating the half shafts.i dnt think your trans is gonna die so follow this trail====Guibo-driveshaft-u joint-center support bearing-u joint-driveshaft-u joint-fluid level check-rotation by hand-(if L.S.D open diff and check for Clutch wear)

[wasabinuki]

Your transmission is about to die.

[Tom Brady]

Bump

Anyone figure this one out? Same year, Same make, Same model: Same problem.

If my tranny is about go I'd really appreciate the heads up but if the problem is in the driveline, at least that I could realistically have fixed. What I absolutely dont want to happen is to have either replaced or repaired and it turns out the problem was in the other.

Please somebody lmk what you think, thanks!

[lateracer]

My transmission eventually went bad and I sold the car as a 5spd swap candidate that was capable of limping to wherever it needed to go.

I eventually got the car up on a lift and watched it go through gears with the park brake engaged a few clicks to simulate a load. Driveshaft was worn out, diff bearings spun, cv joints were at the end of their lives. The clunk was definitely from the trans, but the rest of the drive line was amplifying it.

Judging by the carfax report for my car, the trans had just under half a million miles. Can't really complain I guess.

In hindsight, I should have put it on the lift to watch it run right away. I didn't spend much $$ to chase down the problem, but I spent countless hours tightening bolts that were already tight, reading discussion threads that were wild goose chases.

Occam's razor; the clunk from the transmission turned out to be the transmission.

[saxguy09]

Bump

[3liter6]

Subscribed....same car. EXACT same problem. EXACT.

Yup. Anyone figured this out yet?

[wasabinuki]

Just replaced the sub frame mounts on the kids car (325is auto) and the problem went away.

The clunking issue, or the car ride height difference between gears? Or both?

[twistednut]

Just replaced the sub frame mounts on the kids car (325is auto) and the problem went away.

[wasabinuki]

OK - I am still working on locating the source of the problem, and I have a little more information to share. I can get the clunk to happen every time I pump the gas, though not as pronounced as when I am coming to a stop / downshifting - it is the same noise coming from the rear end ( sound like under rear seat). If I place my hand on the driveshaft tunnel in front of the rear seat I can feel the clunk coming from further back in the driveline.

If my rear SFB and/or RTAB are bad, would this cause the problem? Any way to test those without removing the rear end?

Another odd thing also happens. If I have my car in park and put it into reverse, the whole rear end of my car raises about 1". If I put the car in neutral it goes back to park height. If I put the car in any forward gear the rear end drops about 1". I have driven other auto E30's and they don't do this. Is this normal for autos? Could this be a cause/symptom of the clunk? Tranny mounts?

Any further help with this issue would be very much appreciated.

[lateracer]

Thanks for the link/info, but $750 is way too expensive. A 5 speed swap will be about the same amount of $$$, so I'm going that route. The only drawback will be driving in traffic now.

^x2...the only reason I got the stupid automatic (instead of a 5 speed) was for mindlessly sitting in traffic. I'll be damned if I'm gonna pay that kind of money to fix the slushbox.

Think I'm gonna just clunk through life with the 4hp22 until it shits the bed (or the 805), tow it home and do the 5 speed swap.