I have a 1994 Chrysler LHS and the reverse gear has been erractic lately. The car always started fine but when I put it in reverse it would grind and vibrate like it didn't want to budge. I recently installed a new starter and battery, so this has made a major difference. Now when I put the car in reverse it grinds and vibrates really bad. I also have to push the brakes to the floor because if I don't the car will literally take off. Not sure what this could be but open to any suggestions.

 

Ok so out of the blue the reverse gear doesn't grind but still vibrates. I have noticed something else with the car that might be related. As I'm riding down the road doing 40-45 mph all of a sudden the speedometer drops to 0 mph and the car halts and jerks for a split second then back to normal. What could this be? Once again, I'm open to any suggestions.

 

I just bought '99 LHS 2 weeks ago and one of the rear rotors is gouged pretty bad. I wouldn't say that the car grinds when backing up, but it sure does howl. The problem on my car definitely seems to be coming from the rear so that I am pretty sure that it is the rotor ans not the tranny which should produce a noise from the front end of the car.
I've never had an automatic tranny make a grinding noise and I've had plenty of them fail. I would check the brakes and wheel bearing (all around, not just the rear) to rule those out.

 

I had a '99 Bonneville that did something similar.
I could be going down the road and I would hear a "pop" through the stereo system, all of the gauges (and those cars have a lot) would go from off to all the way to the right and then all reset to where they should be...kind of like they do when you first start the car.
It ended up being a loose + battery cable.
Check that first...sometimes it isn't as complicated as you would think

 

I just recently had the brakes and rotors changed on the front and rear so I don't think that's it. About a year ago I also replaced the cv axel so I doubt if that is it but I will look into! Thanks.

 

No I don't think it is a battery problem. The car could literally give you whiplash it jerks so hard so it is more than a "pop" and nothing happens to my lights or the radio. Its just the speedometer and all the gear lights come on at once PRND...etc