How can one find out if a U-Joint is going bad? Any sounds or tech problems I should know about? Thanks.

 

A clunking noise every time you shift is a great indicator or vibrations at xxx mph

 

when mine broke, it rattled so much my teeth chattered on less than perfect roads. loud noises are also a good tip-off.

 

is this expensiveto change ??

 

$248.20 from mazdatrix, and that's a driveshaft with a replaceable u-joint. The stock u-joints are non-replaceable, you have to replace the whole driveshaft.

http://mazdatrix.com/g9.htm

 

It only happens when I get into first gear. Is it still this?

 

If its only in first you could have a transmission problem.

 

Clunk in lower gears = front U joint, clunk in higher geras rear U joint. It may well vibrate before you hear the clunking. Be cautious, before assuming only the U joint also rule out motor/tranny mounts as well as diff mounts.

 

1. the OEM U-joints are staked in and slightly difficult to replace, but not impossible. Search for the threads I had running a while. I replaced mine for $20 a piece (give or take a couple bucks)

2. The easiest way to tell if a U-joint is going bad/is bad is to remove the driveshaft (30 min tops) and rotate the yokes in a 360. If it doesn't spin easily, then the U-joint is seized and needs to be replaced. If you remove the driveshaft, mark the rear-diff and the driveshaft so you can re-install the driveshaft exactly the same way it was removed to avoid problems later.