Clunk! Clunk! at the back

[superfans]

Have you guys experienced any clunking type of noise around the engine area when you step on the gas pedal from a stop?

Somtimes when stepping on the gas pedal, the car (996 tip) will not accelerate immediately and the engine will jerk a little and create the "clunk" noise. This also happen when the car is rolling along without gas and then tap on the gas pedal (particularly in low gears). It feels like something was dropped underneath the car.

[rbcsaver]

sounds like a CV joint.
regards,
Steve

[zachsbug]

Yeah sounds like a cv. Mine was doing the same thing. Took it a part & sure enough it was all busted up.

[superfans]

I have taken the car to the dealer and the mechanic told me that the U or CV joints are ok. I explained to him that a clunking noise will sometimes appear when I accelerate. Furthermore, there is a momentary hesitation when I accelerate. The mechanic also said that the engine and transmission mounts are ok. What esle can you guys think of which may be the cause of this noise? Thanks in advance for your help.

[bigchillcar]

well, what did the mechanic think? did he not give his opinion?
ryan

[rcecale]

I've been chasing a "clunk" on my 86 Carrera for a little while now. CVs were checked. Took a look at my output flanges and differential, which a local p-car mech said were okay. He suggested looking at the sway bar. Sometimes the mounting brackets and such come loose. Argh, mine were snug, but it might be worth a look.

Randy

[zzwhm]

I chased a clunk for several driving events on my Carrera. It was a clunk from the right rear when the weight of the car would transition. Sway was ok and I replaced the CVs, but it continued. Turned out to be a cracked right rear wheel bearing.
Bill

[superfans]

Guys, thanks for your help. The dealer said the engine and transmission mounts are tight and ok. They have checked the sway bar and it is fine. I'll ask them to have a look at the rear bearing as well.

[superfans]

Dealer said the bearings are ok. Do you guys know what else could have caused this "clunk" sound?

[Nitrometano]

A lose brake pad? or wheel?

[Bobboloo]

It sounds to me like the tranny. Sometimes my Mercedes will do this because the tranny isn't completely ready to accelerate because 1st isn't fully engaged. You hit the gas and the motor revs slightly before it drops into gear and you get a clunk. It's an automatic tranny kind of thing. Adjusting the govenor might be needed or a vacumm line.

Try to take notice as to when this occurs. i.e. What set of circumstances occured right before the clunk.

[superfans]

Actually when I am cruising at around 10-20 mph and accelerate slowly, it does not have that "clunk" sound. However, if I step on the gas hard, then it will "clunk" (only once) before it shoots off.

[87924gt]

Check the shocks, sometimes the top nut will need to be tightened. Keep it simple first, than start spending $.
Steve

[bigchillcar]

sounds like some kind of 'slack' in the drivetrain..always makes me think of ring & pinion wear, but seems so unlikely. could it be clutch related? just thinking out loud..
ryan

[superfans]

Could the clunk sound cause by a bad spark plug?

[bigchillcar]

superfans,
you don;t say where you're located, but if it's cali by any chance, i'd ask a local pelican to help out if you've lost confidence in the dealer troubleshooting..from cv joints to spark plugs now..i haven't a clue, but in my defense i have no experience with the 996. sounds like you need an experienced troubleshooter to hear it.
ryan

[oneblueyedog]

You should check out northcoastcab's post on this. He didn't say it was definative but the last thing he replaced was the wheel bearings and it went away. BTW the removal write up was a very good one.