bryan c

When I hit second gear hard, something towards the rear clunks loud and hard. It's usually 2 or 3 clunks in quick succession. I eliminated my y-pipe banging with a poly drivers side motor mount (that install was a pain, literally), so I'm guessing my clunking is suspension related, but I guess it could be the exhaust in the rear. I have SuperMaxx headers and catted y-pipe going into an SLP 2OTL. My suspension is stock except for BMR square sub frame connectors and BMR bolt-in relocation brackets. Any ideas? Thanks for your time.

Lt1FBoDy209

where is the clunk coming from?

bryan c

toward the rear, possibly the passenger side.

fugasi

iTrader: (3)

Push down on the back of your car and see if you hear the clunk. Mine was doing something similar (though not just in 2nd gear). Ended up that the torque arm bolt (transmission side) broke. Torque arm was banging the underbody.

JohnnieMo

I have had that exact issue for quite some time now. I only notice it under hard acceleration or during burnout at the track. It is a bunch of quick bangs. It coincided with my supercharger install. However the car has been on the hoist and thoroughly checked out. More recently I though it was coming from nearer the tranny where as before I thought it was in the back.

I attributed it to wheel hop, but I can't be sure. Suffice it to say the car is in the shop for a complete suspension overhaul. I'll let you know if we find anything that may have caused the problem. It better go away!

bryan c

I do have some wheel hop, but something is clunking/banging that shouldn't be. I'm going to crawl under the car this weekend and investigate everything thoroughly. The clunk is so hard, there has to be some evidence. I figure if I can't find it, that it will break sooner or later, and then I'll know what it was.

99BirdLS1

i have a similar problem, look at the torque arm busing on the transmission side.

SLIKWS6

iTrader: (6)

Did you tighten down your lca's to the relocation brackets to their proper ft-lbs?

I think thats what it is... let me know

98-mongooSSe

iTrader: (2)

I've got the same problem. I was hoping that a TQ arm would eliminate it as it only happens during wheel hop.

Shay

JohnnieMo

Well I found the answer..... none of my upgrades fixed the problem, but I think they helped.

The rear suspension is simply bottoming out. My buddy in an 02 had it happen once too. I checked the bump stops and they are noticeably "clean".... meaning they impact regularly.

I tried stiffening the shocks, but it didn't help. So I found the problem... now what?

https://ls1tech.com/forums/drag-racing-tech/318837-hitting-bump-stops-launch.html

LS1FIRE

iTrader: (1)

I had some clunking noise too. Turned out my tranny mount and torque arm mount was all tore up.

69_YENKO

iTrader: (16)

Check your torque arm mount. i had the same "clunk" during burnouts and hard acceleration. my stock T/A mount was torn and beat up badly with a large peice of it missing. I replaced my T/A and tranny mounts with poly peices from energy suspension and the problem was fixed.

I lowered the rear of the car alittle this weekend and now im getting some wheel hop from the angle of the LCA's being off so much.

JohnnieMo

I guess I'll take a look. The torque arm was replaced with a new SLP one... but I didn't do it myself. I'd hope the guy would have noticed any issues.

Forgive my ignorance, but does the T/A mount get replaced with a new torque arm?

69_YENKO

iTrader: (16)

im not sure, the stock bushing is rivited into the mounting bracket. so to replace it you would have to drill out or grind off the rivit heads.

JohnnieMo

Well I tried to get under the car, but the damn thing is just too low. Its going into the shop next week for a different reason, so I'll look at it then.

However - I'm prepared to rule out bump stops now. I went road racing this week and I noticed the same bump on hard braking. After the run you have to stop in the stop box. So it is a hard brake. When the car stops there is a clunk. Then as you slowly accelerate out of the box the clunk hits again. It simply has to be the torque arm. So I'm going to look at everything down there and see what is missing.

CAMSS30

Check where the tq arm mounts to the rear end, acctually above that point on the underside of the body (up in the tunnel above the rear tq arm mount), look for small dents in the body from the tq arm and mount hitting.

JohnnieMo

Upon close inspection it looks like all the torque arm mounts are fine. However there is a small bracket that holds the e-brake line in the drive shaft tunnel. It is right above the torque arm. When the rear suspension compresses, this bracket hits the torque arm!!! The tolerance is maybe 1/2" at most.

My car is only lowered by removing the rear isolators, but the whole car sits really low. There is only about 5/8" to 3/4" between the rear bump stops and the axle. I'd cut down the stops, but then the torque arm would REALLY hit.

So I don't know what to do now. You can't move the bracket and the torque arm can't move. I guess some relocation brackets will help the rear end push up on launch, but that is about it.

bryan c

I still haven't solved my clunking, I'll check out my e-brake bracket.

Silver02

iTrader: (1)

Since I had my tranny beefed up, mine clunks hard on the 1-2 shift. It's like something is hitting the floor board behind the driver in the middle of the car. Tranny mount and torque arm appear tight.

JohnnieMo

That is exactly where we traced mine to and found the ebrake line bracket. Get the car on a hoist and find those brackets. Then use a little mirror to inspect the top of the torque arm. I'm almost certain you will see some evidence of impact.

I'm really at a loss on how to fix it. My car did it at the stock ride height as well, so sticking the rear isolators back in would be useless. LCA brackets should fix it, but that isn't a fulltime solution.