ok its an auto. i just put new tires on it and that helped a little. when im at about 5000+ it vibrates like crazy and makes the cd player skip. i know my u joints are going out and i was thinking these were related but now that i think about it it seems less like that would be thed cause. its not so much of a speed problem but an rpm prob. when im going 70 in fourth and get on it and it goes to 3rd it vibrates a whoooole lot. any ideas??

the u-joints, Ujoints are engine rpm releated

and did you get a alighment?

U-Joints in the driveshaft AREN'T engine RPM relative. They're speed relative.

My car does the same thing. I cant listen to my CD player anymore cause the vibration is so bad the cds skip. In mine though the vibrations start at about 40 mph not when im at a certain rpm like shane. If it is the U joints how easy are they to fix?

The U Joints on the D/S aren't replaceable (unless you have them machined)...You have to buy a new D/S or a used one with low miles...I recommend buying and new one or a remany, as I've bought 2 used ones a BROKE both of 'em. New D/S goes for about $239+.

and the used ones have replaceable u-joints, don't they?

Not that I'm aware of..every one I bought you couldn't replace. I think thats with all D/S from (2ndGens-My only exp)RX7's.

ok its not the u joints but the rear tranny mount is in pretty bad shape so im gonna go with that being the cause. also if you get a new ds you can get them with replaceable joints, or you can find a shop that will cut the ends off and put new ends on that have replaceable joints. there is a place here in my town that does it and its a small town so look and ask around someone there might do it to. oh and the u joints arent that easy to get to bc you have to remove the exhaust to get the ds off. look at the fsm there used to be one at fc3s.org but it hasnt been there in a few days.

I know on 2 cars of mine that had bad ujoints when I put

the car in nuetral at speed it would smooth out, back

into gear it would vibrate again, so when under load the ujoints

caused the vibration

And you're positive the u-joints were the problem?



The driveshaft is always spinning at the same speed the car is moving. If there is vibration at speed, then there is too much slop in the driveshaft u-joints, and they need to be replaced. I can't see it being in gear a problem, unless there is another underlying problem that contributed to driveline vibration. Especially not engine RPM related at all. Maybe if the driveshaft was bolted to the flywheel, but...