Chaotic Firebird

Every once and a while, when I shift my car from P to R, or P to D, I will get a loud bang coming from the floorboard. I'm guessing it could be my y-pipe hitting the floor, but what would make it do that? Broken hanger, bad motor mount ??? I'm still on the factory headers and y-pipe. I'll be swapping the headers for SLP mids and a RandomTech high-flow dual-cat y-pipe this spring. This bang only happens when I'm shifting from P.

Ralls

iTrader: (32)

I would say replace the tranny mount and see if that works. Thats what I did.

Chaotic Firebird

I had a poly mount installed in the spring.

Ralls

iTrader: (32)

Did you perhaps install anything else not in your sig? Like torque arm?
Does the driveline seem loose at all? Like if you snap the throttle at high rpm.

BlkLs1WS6

dont really know a lot about Fbodys yet, but it would seem to me that if your y-pipe was loose, then it would rattle or vibrate all the time, or at least when you went over bumps in the road, not just when you shifted it.

Ralls

iTrader: (32)

Yeh I know it isn't the exhaust hitting. Cause then you would feel it hit every time you get on it.

It is probably the drive line. When you shift through the gears, it changes the pinion angle. So if you have a loose u-joint or bad torque arm, there will be flexing.

Chaotic Firebird

I'm still running the stock steel driveshaft and stock torque arm. But I do want to get an aftermarket torque arm this spring. My driveway has a slope to it, and the car does feel a little rough when I shift out of park into reverse. Like something is hitting something else. The only thing I installed that's not listed is an RK Sport tunnel brace, but that would give more room between the driveshaft/exhaust then the stock peice did. And the noise was there before I had the RKSport part.

I did notice a slight banging noise when I would come to a stop on a decline a couple times. So maybe it is my torque arm?

Ralls

iTrader: (32)

It's possible it could be the torque arm, but I wouldn't get a new one for this. The best thing you can do is get your car up on ramps, especially the rear, and fronts for safety. You want to simulate suspension load. Then have someone change gears while your under the car. Gota find out where the noise is coming from. It will also show you if anything is loose and flexing.

Boodyrider

iTrader: (2)

It's almost certainly the trans mount. get under there and look.

Ralls

iTrader: (32)

It SHOULD be the trans mount I know. But seems weird it would go bad so soon.

If you don't figure anything out by listening under the car. You might need to go to your local parts store and get a rubber tranny mount. $5 could solve this...

Chaotic Firebird

What about the motor mounts? I know when I had a bad mount in my truck, the engine moved around a lot and things would hit each other.

1SlowFormula

How many miles are on your car? My car has a little over 80K on it and a lot of track runs, and a few months back I changed to poly mounts for tranny motor and t/a because of a similar issue you refer to and the tranny and motor mounts were shot and the t/a mount was getting there. Doing all the mounts wasn't too hard to do, and rather cheep considering all the poly mounts costed less then $100...

Ralls

iTrader: (32)

The motor mounts shouldn't be the problem. If the motor mounts were bad, you would bang under WOT load. You sure it only happens switching gears? Doesn't bang WOT or launching?

Chaotic Firebird

I'm pretty sure it doesn't bang under WOT, but sometimes I'll hear a small bang when I let off the gas after WOT. But it's mostly from shifting gears in my driveway, or an incline. I'll have to find a decent day to drive my car to see if it bangs before and during WOT.

Ralls

iTrader: (32)

This might seem very simple, but it may be the problem. I've noticed you have been saying "incline," but it didn't seem to matter before. Are you applying to parking brake when you park your car BEFORE you let off the brake? Cause if you load the car's weight on the transmission and not the brake, you are putting pressure on the a "hook" that grabs on the flywheel (or some other gear?) . Then when you switch out of gear, it makes a loud noise to try and let go of the gear.

1SlowFormula

Good possibility of that, I know my car does that if I'm on an incline...

Chaotic Firebird

Well my driveway levels off at the top by the garage, so I don't apply the parking brake there, but I do when the car's parked further down. If it is the flywheel thing, should I be worried about it?

Also, I'll have the torque arm bushing checked when I get a chance. Some people have been saying that a bad bushings, loose bolts, or a cracked mount can cause the clunking. But could have lowering my car with the WS6 springs thrown off the pinion angle of the torque arm? Or was the drop not drastic enough to hurt it?

Ralls

iTrader: (32)

As I was saying about the flywheel.. I realized it can't be the flywheel because it has to spin at start up. But none the less, some gear is held on to by a hook to stop from moving. But if you are saying the level is flat where you park, this shouldn't be the problem.
Go ahead and check for bad bushings and loose bolts. I would assume lowering your car will change the pinion angle, but no one ever says anything about readjusting it once you lower your car. The stocker can't be adjusted anyways. I don't know if I asked before, but did this start happening right after you installed something?