While I was exiting an on ramp turning right the other day, I hear this loud bang come from under the car. It sounded as if it was towards the back or middle. I wasn't pushing the limits of my car, nor was I driving like a grandma. On the rough road the car keeps going bang bang as if the driveshaft is scraping the ground every time I go over a bump. I pull over, and see nothing wrong underneath. I begin to drive slowly, and there are no noises. I put the car in first around 10-15 miles an hour, and give it 3/4 throttle, and hear the same noise. I drive back down the bumpy road and the noise is still there over every bump. It's so violent it bounces my parking brake lever up, however the cable is disconnected.

I put the car on ramps, and see nothing obviously wrong. Mecham TAs came with a steel wire that held the rear end to the rear subframe so the springs don't fall out when the cars on the lift. I noticed both were broken, they looked as if they rusted over time, not as if they snapped recently.

One thought is that the tranny mount could be broken, but I've never had that happen before, nor do I know what that is supposed to sound like. Any idea on what the noise is?

 

I doubt it's a trans mount. That type of bang/impact usually only occurs @ launch during a holeshot. I have one to replace. Your situation sounds like broken shocks or mounts.
I'd thoroughly check the rear suspension including bushings.

 

It culd still be a tranny mount. Easy to diagnose. Jack up the car, crawl under and push up on the tranny's tailshaft real hard. If the mount's toast you'll see the rubber part of the mount separate from the metal part, or the rubber itself can be ripped in half. When you let it back down the 2 halves will come back together perfectly and it'll look totally normal, like there's nothign wrong with it at all.

 

It could very well be the tranny mount. That would be my first guess. But, if that isn't it, look at your torque are mount. The rubber could be worn out ant the arm could be hitting the metal part of the mount. This is something that wouldn't be obvious. Try jacking the rear of the car up with jackstands under the rearend, keeping the suspension loaded. Grab the front of the torque arm and try move it up and down. If the mount is good, the arm shouldn't move. If it moves, replace it!!! I would suggest getting aftermarket poly bushing. These are much stronger. If this is the problem then you will have a quieter ride and better traction in the holeshot.

 

Id get underneath and visually and by feel check all the rear suspention components and everything around the trans.

 

Given that it makes the noise when you give it gas Id say the trans mount would be a likely suspect.

 

It was the tranny mount. The old one had a tear or two, and the metal on the inside just spun inside the rubber.

The old one had a lot of grease on the inside; which confused me because my Uncle said grease could deteriorate the rubber, so I installed the new one as is. Any imput on this?

 

I've never lubed a trans mount. Of course, I use polyurethane though.

 

How much worse are the vibrations with a poly mount?

 

Probably alot less vibrations then the current one had . I wouldnt sweat using a poly one.

 

definetly got with a poly one...they hold up better and u can install and forget em...most of the time

 

How hard were they to change, did you have to drop the transmission?

 

nope, takes about ten minutes. unbolt the trans mount from the cross member and trans, put a piece of wood on a jack and lift the trans off of the mount, and then slide the new mount in and torque the bolts down.