*BANG* coming from the rear of the car - thoughts???

[Morpheus]

Is it happening when you change direction, i.e. turn left or right for the first time after the opposite direction? Rear wheel bearing shifting in the carrier is a pretty common complaint.

We were driving straight when it happened most of the time. We drove around a parking lot making sharp turns and, while we heard a few clunks, it wasn't the same sound as the very loud BANG BANG we heard while driving normally.

[DMage]

Can you make it repeat and under what conditions? Is it a mechanical noise? This is really difficult to help with. Check the mounts on all of the shocks. Check the sway bar brackets and mounts. Check the lug nuts. Could it be the motor backfiring? Can it be something moving around in the truck?
David Teitelbaum

Rear shock mount nuts are in there and double lock nut secured. Rear shock mount to lower arm is secure. Lugs were tight, checked that in the parking lot. Noise is coming from rear so not sure how the front sway would impact it. Trunk was empty. Could it be a backfire? I guess its possible, but the engine idles perfectly and has for the past 7 years I've owned the car. Still has the mixture plug sealed. The only difference recently of things I have done to the car are replacing the gas with non-ethanol 91 grade gas. Would that have an impact on a backfire? I wouldn't think so. This sounds more like a mechanical / metal bang then it does like an explosion.

Is it happening when you change direction, i.e. turn left or right for the first time after the opposite direction? Rear wheel bearing shifting in the carrier is a pretty common complaint.

I've heard that noise before, and this is much louder and more random.

Are all the frame to body bolts tight?

I can check them, but we did push and move the car every way we could and had no movement.

We were driving straight when it happened most of the time. We drove around a parking lot making sharp turns and, while we heard a few clunks, it wasn't the same sound as the very loud BANG BANG we heard while driving normally.

And when we left the parking lot I was cruising in 3rd gear at 35mph and it did it. We were going on a slight left gradual curve at the time.

[Evildeli]

. Could it be a backfire? I guess its possible, but the engine idles perfectly and has for the past 7 years I've owned the car. Still has the mixture plug sealed. The only difference recently of things I have done to the car are replacing the gas with non-ethanol 91 grade gas. Would that have an impact on a backfire? I wouldn't think so. This sounds more like a mechanical / metal bang then it does like an explosion.

When I start my D up, I usually let it run idle at least 6-10 minutes before driving. If I rev the engine before the 3 minutes marks, most times I'll get a misfire pop. However I never get that pop after the 6-10 mark. You said the engine was hot, so I would guess it's not backfire. Just my guess though.

[Ryan King]

My vote is on a CV Joint

[stevedmc]

This is one of the benefits of being single and having no kids. When my car makes dangerous sounding noises I just keep driving. If/When I die, it doesn't really matter.

In all seriousness though, I would check your TABs and all the other stuff everyone is mentioning. TABs were my biggest fear when I got my car, and upon inspection I found one had rusted in place and was bending. At the time I had a girlfriend and it really would have sucked to have had something bad happen while she was in the car.

[David T]

You could try jacking up the rear tires and running the car in gear while you carefully go looking for the source of the noise. It *could* be a C/V joint. At this point it can't hurt to pull the half-shafts, disassemble them, lube them and replace the boots. Make sure all of the bolts in both half-shaft to output flanges are in tight. Check the oil in the transaxle. If it is a backfire you might notice a momentary loss of power in the gas pedal.
David Teitelbaum

[DMage]

Thanks. Going to give that a shot tomorrow night as well as crawl all around under the car again - but being just under there yesterday for the slave replacement, nothing really stood out.

Oil in the tranny should be good, replaced it several years ago and my case has no leaks.

Another thing, not sure if its helpful - I've had a noise for the past few years (car doesn't get out much - maybe 1500 miles in the past two years) in the rear of the car on the highway. Sounded like brake pad clatter, and went away when tapping on the brakes, but it was definitely RPM related. Was a noticeable but quieter clicking noise. I did several things to try to stop the brake pads from clattering but maybe it wasn't the issue and is related to this?

[DMCMW Dave]

It's a hard one to spot but I've seen trailing arm bushings fail and do this. You need to remove the trailing arm bolts and check the bushings.

[DMage]

It's a hard one to spot but I've seen trailing arm bushings fail and do this. You need to remove the trailing arm bolts and check the bushings.

Can do, will check tomorrow, thanks for the idea. That makes sense as I assume it would bang around in the frame if the bushing went. Should be easy to get the Toby Tabs out.

[DMage]

Wanted to wrap back around to this - the issue was discovered after poking around under the car for several hours on Friday. The upper bushing on the DMCH drivers rear shock split in half and was sitting wedged between the frame and the pontoon. The shock must have been rolling around in the hole and banging back and fourth. Luckily there was less than 2 miles put on the car since hearing the noise and just driving it around the neighborhood, so I imagine any damage is minimal to the shock or the frame. Talked to Stephen at the Celebration show on Saturday and will get a new bushing sent out sometime this week.