rear end clunk when releasing clutch

s3cf
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rear end clunk when releasing clutch

Postby s3cf » Fri Jan 06, 2017 3:57 pm

hello

I noticed that there's clucking noise from the rear end when clutch is release

example
1) clutch in
2) put in reverse
3) clutch out / gas
4) clunk from the rear, car starts to move

If I let out the clutch gently, no clunking noise

Car drives absolutely fine and shifts smoothly

what's the potential problem? any idea?

Thanks

totta crolla
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Location: Oxford U.K

Re: rear end clunk when releasing clutch

Postby totta crolla » Sat Jan 07, 2017 12:39 am

Only in reverse ?
If your car has rear disc brakes it could be that the pads are dragging on the disc and being pushed back against the carrier. Otherwise check all of the rear end suspension bushes. Does the car have a limited slip differential ?

s3cf
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Joined: Mon Jan 14, 2013 9:40 pm

Re: rear end clunk when releasing clutch

Postby s3cf » Sat Jan 07, 2017 10:17 am

totta crolla wrote:Only in reverse ?
If your car has rear disc brakes it could be that the pads are dragging on the disc and being pushed back against the carrier. Otherwise check all of the rear end suspension bushes. Does the car have a limited slip differential ?


Thanks for your response
Reverse seems to be the most noticeable, I think it happens to other gears too esp 1st and 2nd. If I let out the clutch gently, there's no clunk noise at all.

Getting back to your question, car has rear disc brake and with oem LSD. Car has new bushing kits installed (the entire car)

Look forward to your comments
Thanks

totta crolla
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Re: rear end clunk when releasing clutch

Postby totta crolla » Sat Jan 07, 2017 10:49 am

Ok, check very carefully every joint on the driveshaft (propshaft)

SgtRauksauff
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Re: rear end clunk when releasing clutch

Postby SgtRauksauff » Mon Jan 09, 2017 11:49 am

^^^ what Totta said. driveshaft U-joints, also check to make sure your shocks/swaybar links are tight, and make sure your panhard rod and the rest of the suspension bolts/nuts are tight. if everything's new, sometimes they seem to loosen a bit once things have compressed and 'settled in'.

If you know someone at a lube place, you could be in the pit while someone releases the clutch for you, and zero in on the problem quickly.

s3cf
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Re: rear end clunk when releasing clutch

Postby s3cf » Mon Jan 09, 2017 3:10 pm

^ thanks, will look into it

notnilc20
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Location: Memphis

Re: rear end clunk when releasing clutch

Postby notnilc20 » Tue Jan 10, 2017 9:12 pm

s3cf wrote:hello

I noticed that there's clucking noise from the rear end when clutch is release

example
1) clutch in
2) put in reverse
3) clutch out / gas
4) clunk from the rear, car starts to move

If I let out the clutch gently, no clunking noise

Car drives absolutely fine and shifts smoothly

what's the potential problem? any idea?

Thanks


If it's always done this Could be your differential backlash has too much play in it. But if it just started doing it then probably not.

s3cf
Club4AG Expert
Posts: 360
Joined: Mon Jan 14, 2013 9:40 pm

Re: rear end clunk when releasing clutch

Postby s3cf » Wed Jan 11, 2017 8:46 am

notnilc20 wrote:


If it's always done this Could be your differential backlash has too much play in it. But if it just started doing it then probably not.


Thanks, if it was too much play in the backlash, how do I address it? thanks

totta crolla
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Re: rear end clunk when releasing clutch

Postby totta crolla » Wed Jan 11, 2017 9:15 am

s3cf wrote:
notnilc20 wrote:


If it's always done this Could be your differential backlash has too much play in it. But if it just started doing it then probably not.


Thanks, if it was too much play in the backlash, how do I address it? thanks


Try to eliminate every other possibility before going down the route of removing the differential / final drive unit. (ring and pinion)
The backlash is a measurement taken from the final drive and whilst it is not particularly difficult to adjust it will be the reason that it needs adjusting that will likely be the issue.
Most people send the unit away for repair / adjustment.
Have a look here:
http://www.gearinstalls.com/

notnilc20
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Location: Memphis

Re: rear end clunk when releasing clutch

Postby notnilc20 » Wed Jan 11, 2017 12:56 pm

The backlash is the amt of play in between the ring gear teeth and pinion gear. You need a little bit of play....but too much or too little can be catastrophic to your rear end and i'm talking about fractions of an inch. The carrier can be adjusted left or right from the pinion gear to adjust the correct amt of play between pinion gear. Each manufacturer has different specs for different rear ends. Gm uses shims to space it correctly...ae86 has two set spacers on left and right side and threads that allow you to move the carrier whichever way it needs to go. But if you don't feel confident best take it to a shop. You can do some of the work by taking the pumpkin off and taking it to a shop that way to save some money on labor. However like Totta corolla said eliminate all other possibilities first before you go taking your rear end apart.....

I would jack car up on jackstands put car in neutral get under neath car and rotate the driveshaft with your hands back and forth and listen for any noises coming from the differential. There should be a very little amt of play but nothing excessive...yeah i know kinda vague but....there are some good vids on youtube explaining how and what backlash is with demonstrations.

Good luck.

MisterJerk
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Re: rear end clunk when releasing clutch

Postby MisterJerk » Tue Jan 24, 2017 11:22 am

I too had this going on. Replaced center ds bearing, front drive shaft, etc.

Ended up being the oem lsd had broken. Which i figured out when it popped and started grinding.
https://m.imgur.com/a/9sHzD

My pics are too big, so see this album.