Light 30mph+ vibration

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Sep 21, 2006
I am getting a vibration from speeds 30mph and everything above that. That vibration is light and not in the steering. Not bad just enough to annoy you. Engine speed, load doesn't seem to make a difference. I replaced my m/t tires with a/t which is when I noticed it. I think the m/t tires may have just been hiding it. I took the new tires to be reblanced but it feels the same. Front wheel bearings are also new and have no play. Front drive shaft was replaced. Does this even sound like a driveline problem? When I crawl under the ujoints don't have any noticeable play. There is a tiny amount of play in the t-case output shaft not even measureable but you can see it move slightly if you really try.
I used to work on drivelines some years ago and it could be a driveshaft issue.

But it seems odd that it started with the new tires. You could have another tire shop see if they are balanced.

It sounds like you've eliminated the front drive shaft as a problem.

The back shaft could be slightly twisted (You can look to see how well the end yokes line up, it does not take much to throw one out of balance.), or it could have had a balance weight come off, or a rock could have hit the shaft and dented the tube. A good driveline shop will be able to help if you want to eliminate this as a possible source of vibration.
U-joint maybe...
Well I pulled the rear shaft to test drive it and it seemed pretty much unchanged. The u-joints seemed smooth and the shaft looked ok. The slip yoke has a little rotational play, is that normal? Also how bad does a bad u-joint feel? Are we talking any stiffness at all even at the limits of movement or more or less smooth movement where it would normally ride? I might pull the front shaft again and see what happens. When I first installed it I put it 180 degrees off and it vibrated for a while before I figured that one out, so maybe that messed up a u joint or something. The tires are BFG a/t and I watched the guy stuggle to get a couple balanced but ended up with a zero reading on the machine when finished. This was at Discount Tire.
Actually, when I replaced mine, it had a barely discernible catch in it when I rotated. But when I took it apart, the needle bearings in one cup were totally turned to dust and it was dry in there. The cap also had an easily seen crack all the way through. So... it may not be easy to tell just from dropping it and rotating it around. But once you get in there, you can tell. Since you have the rear shaft out I would just lock the cdl and drive on the front shaft and replace the rear joints if you can.
I actually already replaced the rear shaft after the vibration didn't change. Jumped the gun I guess. I am going to pull the front and see what happens. Kind of a bummer the only way to tell is to take it apart at which point why not replace it anyway?
Well pulled the front shaft and the ujoints seem bad. They have some real stiff spots. I also realized it was a used shaft I put it so maybe the ujoints were on their way out. But even without the front shaft I am getting the same vibes. I am going to call around to get the ujoints on the front shaft replaced while it is out. So with either the front or rear removed I am getting the same vibration. I guess that rules out a drivetrain problem. Unlikely both shafts are bad and cause vibes at the same speeds or could I be wrong on that?
Get good ujoints (Spicer). The only way to be sure with driveshafts is to get them balanced at a good shop.
LC's have a alot of torque. Driveshafts are usually designed to be the first part to fail versus a diff/axle/trans/ect. They tend to twist a little over time. Alot of times they can be straightened without replacing the tube. It also depends how hard you off road. Spinning tires that suddenly get traction puts a big load on the driveline. We would get driveshafts from big mining trucks that had ripped the tube in half sometimes..
You can have a thicker walled driveline built but run the risk of something else failing.
I haven't tried a different tire because I don't have one (other than the spare). I was thinking of just doing the ujoints myself but maybe I should just take the shaft to a shop to be sure it is fine.
Bad news the only driveline shop within and hour drive closed down. Maybe I will do it myself. Any places the do ujoints other than driveline shops?
NAPA here in Phx does them. Check prices. If you want do it yourself and have not done this B4 look around online for instructions with photos. I've seen some decent instructions with photos. It can be done with simple tools. You have to be very careful not to drop a needle bearing or smash/bend the ears on the end yoke up or dent/crush the tube.
After install you should have smooth motion with no sticky spots.
Got new ujoints up front. Nice and smooth movement. Installed it and it made no difference. Running out of ideas. Im guessing it is not driveshaft related at least. Where else should I look? Is there any other way for the tire shop to make sure the tires are round and ok other than balancing?
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I checked visually and they look ok. Is there any way to really tell?
After getting the tires balanced 2 more times that solved some of it. I found out why the ujoints didn't improve anything. One of the caps spins in the hole. Hopefully it is just because I used some GMB joints.They say made in Japan but I guess Japan makes crap as well as quality stuff. Maybe it was in Chinatown. They seemed almost too easy to get back together like the caps slightly smaller.I just had to tap them in Vs. using a press to get the Toyota ones out. New Toyota U joints here I come. In the meantime Im just leaving the front shaft out.
It's hard to tell who make what anymore. Or what's been repackaged.
That's not good to have the ujoint cap doing that. Removing the caps is usually harder since they've been in a harsh environment for a long time. It's ok if the caps can be tapped in with a ball peen hammer. But once it's in the cap must not spin. Otherwise the end yoke might be worn. If it still spins you need to get a new yoke put on.
(Or, if money is really tight): This is not recommended but if it still spins you can take the corner of a small chisel and make small dinks around the inside of the hole to gain purchase on the bearing cap. You do run the risk of distorting the cap though. If it's going in too tight you will have to grind back on the divots you made. Another 'ghetto' option sometimes used is to weld a some small spots or a bead around the inside of the yoke hole and grind it back down until you get a grip on the cap.
I'm not sure who makes the toyota ujoints. I wish I new. I just greased mine. The rear joint was pretty dry. So I'll be looking at replacements in the very near future.
Let us know if the GMB and Toyota ujoints look the same!
I know it is not good but I suspect that the GMB caps are slightly smaller. I am hoping the yoke is still ok. When I first installed them and noticed they went in so easy I tried to fit the old toyota cap back on just to compare and it was a little harder. Should the bearing cups and driveshaft be cleaned with degreaser or anything before installing the new ujoints? I thought lube was good to make them go on easy but what do I know? Toyota joints are on the way so I am just wishing for the best.
Lets hope it's just the GMB caps. The new ujoints should need no cleaning. Clean the driveshaft. Blobs of grease and dried mud can throw them out of balance. You might want to get new ubolts, washers, and nuts unless they come with the ujoints. What you want to do B4 installing the new ujoint is take a blob of grease on your finger and run it around the inside of the bearing cap. Make sure the needle bearings are all still in place. Don't use too much grease or you won't be able to install the last cap. If the bearings come out while doing this, carefully put them back in place.
Don't lube the end yoke holes.
When installing the ujoint the zerks go towards the shaft. Put the driveline in and grease the ujoints till it's is coming out of each cap seal.
It is possible to overtighten the ubolts and distort the cap. I'm not sure what the torque spec is. I usually use blue loctite on the ubolts.
Don't forget to grease the spline too!
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I have an update. Got an awesome deal on ebay for Toyota OEM ujoints. The GMB caps are slightly smaller. The OEM toyota joint caps are a much tighter fit and have no chance of spinning in there. Im glad I found this before it wore the hole out and ruined the shaft. The quality is also much better just by looks. I would never use GMB again. I would consider GMB junk since the part does not even serve its intended purpose. I guess other members are right saying Toyota u-joints are worth it but I had to learn myself. I would offer up some free GMB ujoints but I don't think they are even worth installing. I haven't installed the front shaft yet to see the result. I think it may still need balancing.

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