does the rear u-joint do anything when the car is in motion and not in 4wd? I hear a deep rumble at highway speeds and wondered if it was my rear u-joint, but i didn't think it would be moving if not in 4wd, but i'm not sure. any info would be very appreciated. thanks.

every thing moves in 2 and 4wd, but in 4wd there is power to the driveshaft, obviously. even in 2wd the shaft will spin, so if you have worn out U-joints they will make noise.

Easiest way to tell if there worn out is to get under the car grab the drive line near the u-joint and if you can move the u-joint back and fourth and see slop between the round part of the joint and the t shaped section...dang i thought that would be a lot easier to explain...ill try and draw a picture to upload.

Sounds like a bad wheel bearing to me. Does it almost sound like a hole in the floor or wheelwell? If it does, you got a bad bearing. I drove mine for 4000 miles after I started hearing noise. Once I pulled it apart, there was 1/2" slop up and down on the stubshaft

 

Easiest way to check the ujoints is put it in 4wd and go forward and reverse. If the u-joint is shot, you will hear noise as you let the clutch out (as soon as the tranny starts to spin the driveshaft.

if you are speaking of an ea82 car, you can remove the rear half of the driveshaft until you find a replacement. both the front and rear u-joints are on the rear half of the driveshaft

 

also, at and 5spd driveshafts are the same length for the rear half and are interchangeable

 

if the u-joint on the rear half breaks, you can simply tie up the driveshaft (in 2wd only!!)till you replace it, or the rear diff falls out, whichever comes first

mine was seized, couldn't feel it with it in the car, but when I pulled it out to do a clutch job, I couldn't move either joint in the rear half, I replaced it and now the noise is reduced soooo much!!

like just mentioned, in some cases removal is the only way to tell a bad ujoint. i would bet you do have a bad ujoint in this case.

I had a 79 yota once , and the whole car vibrated and roared, I tried everything, in the end it was a bad carrier bearing. (i.e drive shaft center bearing).

 

Do carrier bearings go bad in EA82's often?

wow guys, thanks for the replies. there's not anymore noise if it's in 4 wheel drive or if it's in 2 wheel drive. i got 4 wheel bearings, but i never feel like putting them in, lol.

Well, the back bearings are a PITA to change. I've never had luck with those pounding out the bearings due to the shape of them and the thickness, they need to be pressed in and out. Not to mention you need the ring nut socket which is pretty hard to find. Since you said there isnt any more noise in 4wd I'm thinking wheel bearings even more. Pull the tire off and grab the stub shaft with the castle nut on it. If it moves at all, or has a grab or bite when you turn the shaft, the bearings are toast.

 

If it is shot, best bet is to try and get a rear control arm from a JY or a buddy on the board. 10x easier to change the whole thing than rip apart the old one.