i have a mostly stock FD. i have a lot of play in the drivetrain (when applying accelerator and taking foot off).

i would like to replace my stock drive shaft first because of worn ujoints.

should i get the oem? or aluminum?

does the aluminum shaft on rx7store have replaceable ujoints?

BTW driveshaft info needs to be added to the FAQ

 

Have you physically inspected the driveshaft? You sure it's not the slack in the axle? There's no info in the faq section because they really never fail. The way the Fd's drivetrain is setup (with the PPF system) the driveshaft pretty much stays straight it's entire life span. You can check for slack in the rear end by pulling the parking brake and rotating the driveshaft with your hands back and forward. Mine has more slack than I would like. I'm gonna re-shim my rear end up when I install 4.30 gears. You could also have worn diff bushings and a broken PPF frame. The latter are way more common!

 

+1 worn diff bushings would be far more probable.

Isnt the stock driveshaft Aluminium anyway? If its not it sure is light!

 

Yep. I can almost guarantee you that it will be the diff bushings and possible the engine mounts as well.

 

I'm guessing that you have a broken drivers side motor mount.

 

adam c you are correct, when i did my rebuild i didnt replace the mounts, the driver side was completely broken. dont judge me haha

later oil leaked out from the trans onto the rear trans mount bolts and loosened them (not torqued enough). so my whole drive train is bouncin

diff bushings never been replaced.

when rebuilding my dad noticed the ujoints where shot

so let me get this straight (priorities)
1) replace motor mounts
2) diff bushings
3) ujoints (driveshaft?)

 

Good call Adam.
IF the 'U' Joints really are worn out....which is VERY rare, then replace them with another stock drive-shaft. The extra money for an aluminum shaft would be a waste for an essentially stock car. Arguably a waste in any FD IMO.
You could probably find a good used one in the Parts-For-Sale section or PM a guy named Fritz Flynn. Shipping will probably be as much as the shaft.

 

Although I've never bought one....

Mazdatrix sells an "aftermarket" driveshaft with replaceable U-joints.

The kicker is, it's like $150-$200 cheaper than listed price for an OEM one.

Again though, I have no experience with their driveshaft.

 

Factory shaft is 16 gauge steel.

 

I replaced mine that had over 100,000 miles with one from:
http://www.thrashdriveshaft.com/

Pictures show stock and new.