Are my U-Joints shot?

[70stangcoupe]

I guess I need a better explanation of the U-Joint system. The driveshaft is connected to the transmission by the yoke, and it doesn't use a u joint in the front, correct? The U-joint is used in the rear, where it connects to the differential... right?

Either way, I was up under my car yesterday and I tried to twist my driveshaft by hand, and it moved about 1/4". Should it have moved at all?

I don't baby this car, so it's just a matter of time before the U-Joint busts. Could it be on it's last leg? Should I replace it this weekend?

Thanks!

 

[70stangcoupe]

Anybody?

 

[Grady96GT]

Sounds like UJoints to me...I have been having drivetrain probs too...
I lost a Ujoint and drug my driveshaft up to a parking lot 50feet away when i did a burnout leaving the stoplight.
I went to autozone and bought a brutforce one, put it in on the side of the road...was not fun. Replace it asap.
PS and dont bang on it while it is on the ground with a hammer to get the ujoint in. I now have a nasty dshaft vibration, new one should be here this week. Any other questions PM me.
The ujoints are only like 20bucks

 

[Cobra Jay]

A 1/4" is a quite bit high for free movement. Your slip yoke could be worn down though, just as well as the u-joints. The best thing to do is pull the D/S out of the car and move both the yoke and flange back and forth by hand. If it feels to loose, then yes it's time for some new u-joints. If the yoke is worn out, then I'd just get a new FRPP aluminum D/S and be done with it. The price of a new slip yoke and new u-joints + labor to replce them(if you don't do it yourself) isn't going to be cheap. You'd be better off with an aluminum one any ways. It's lighter and stronger than a stock steel one.

P.S There are 2 u-joints. One on the slip yoke, one on the flange.

 

[COramprat]

Are you getting any vibration while you are driving? I had the same problem but was getting a dull rumble while above 2000 RPM's in each gear. A new u-joint should cost about 30-35 bucks it you replace it yourself. Not to hard. I agree GT Jay though. Just get a new aluminum shaft and be done with it.

 

[70stangcoupe]

If I get a new aluminum driveshaft, I won't need new U-joints? Are they easy to install?

 

[dromeda]

If you get a new aluminum drive shaft, it should come with new u-joints already on it.

 

[GTn00b]

maybe this is what is wrong with my car, everyonce in a while when I go to take off the rear of my car starts to shake and then it stops once i get over 2000 rpm's

 

[COramprat]

maybe this is what is wrong with my car, everyonce in a while when I go to take off the rear of my car starts to shake and then it stops once i get over 2000 rpm's

Mine was more of a vibration than a shake.

And yes...the aluminum DS will have a u-joint.

 

[Cobra Jay]

If I get a new aluminum driveshaft, I won't need new U-joints? Are they easy to install?

If you get a new one from FRPP, it comes complete and everything is brand new.

It took me about 1/2 hour to do mine. The only reason it took so long was because I didn't put mine up on jack stands. I had to keep raising and lowering the car and setting it down on my ramps to rotate the D/S to loosen and tighten it. It's pretty simple to do. All it takes is, I believe it's a 12mm 12 point box end wrench and some blue loc-tite. I used the blue insted of the red just incase I had to take it off somewhere down the road.