1998 LC Vibration at 50-60 mph troubleshooting? (1 Viewer)

[CO 1992 TLC]

When driving at 50 to 60/mph a vibration starts especially while under a load such as a hill or accelerating. Sometimes it’s more intense sometimes less. Cv axles both sides have been replaced a second time after initially installing an aftermarket set and thinking they were the problem, now with OEM CV axles it's still there.
The wheel bearings were repacked and adjusted, the front driveshaft was removed, a test drive was done and the issue was gone without the front driveshaft, inspected the U-joints lubricated reinstalled and the issue is back, swapped the front driveshaft out and still the vibration issue is back.
Wheels and tires have been balanced. (New Bridgestone Dueler Revo 3 - 275/70 R18 with 2k miles, 2018 Tundra wheels 1-1/4' Spacers also 2k miles prior to the vibration issue).

I've tried to search here for this issue with no luck.
Thanks for any piece of info!

 

[Blindado]

I just went through this and my solution was replacing both u-joints on both shafts. Lubing and hoping didn't fix it. They looked pretty ok and weren't sloppy but after 285k and 23 years I went ahead and replaced them. Once I got them apart I could see they were worn just enough to cause the hum and vibration at 65mph and above.

If you do replace u-joints go OEM. Also, there's a video on YouTube of an Australian guy changing his. With a bench vise he presses out the u-joint one way and then grinds that side off to get it all out. That's really the way to do it because if you just remove the cap and then try to press it out the other way it's not going to press through straight and will damage the shaft such that your new u-joint won't be a tight fit.

Once the shaft is in the vise it's quick work getting them all swapped out. They're tough steel so use a grinder and you'll need several good wheels.

Just to state the obvious, be sure to mark everything with a paint pen so you can get the balanced shaft back together correctly.

Good luck!

 

[CO 1992 TLC]

I just went through this and my solution was replacing both u-joints on both shafts. Lubing and hoping didn't fix it. They looked pretty ok and weren't sloppy but after 285k and 23 years I went ahead and replaced them. Once I got them apart I could see they were worn just enough to cause the hum and vibration at 65mph and above.

If you do replace u-joints go OEM. Also, there's a video on YouTube of an Australian guy changing his. With a bench vise he presses out the u-joint one way and then grinds that side off to get it all out. That's really the way to do it because if you just remove the cap and then try to press it out the other way it's not going to press through straight and will damage the shaft such that your new u-joint won't be a tight fit.

Once the shaft is in the vise it's quick work getting them all swapped out. They're tough steel so use a grinder and you'll need several good wheels.

Just to state the obvious, be sure to mark everything with a paint pen so you can get the balanced shaft back together correctly.

Good luck!

Thanks Blindado,
I know hoping wasn't going to solve my issue, I am starting to think it's in the front differential.
I removed the front driveshaft and it disappeared with just the rear differential pulling with center lock engaged, but when I installed the front driveshaft front another Land Cruiser ('99) that doesn't have and issue it's back?
I'm going to change all the U-joints as suggested and give it a shot.

 

[DTCsk8er]

If you've put in another (known working w/out vibrations) front DS and it's still giving vibrations up front, then I'd say the next logical rotating item up front is the CVs.

 

[CO 1992 TLC]

If you've put in another (known working w/out vibrations) front DS and it's still giving vibrations up front, then I'd say the next logical rotating item up front is the CVs.

Both CV's were changed twice, once with aftermarket then OEM CV's thinking the aftermarket might be an issue, with new OEM CV's axles I still the same issue.

 

[Blindado]

I've never been in a differential but I know there are bearings that could wear out. I noted them when I was reading the FSM about the shaft. I too worried it was a bearing, afraid that it had been driven too long with a wonky shaft. But being an LC I'd expect that as long as it's generally been mostly properly lubricated it should be fine. Someone else can speak to this better than I.

My thinking was that I can spend 2 hours crawling around scratching my head or I can be putting in new u-joints that I'll eventually need anyway. At their age and mileage may as well.

Just be sure to watch that Australian guy's video on YouTube. Press out one side and then grind it off, as in the video. Otherwise the shaft can be ruined. I did exactly what he did and all went smoothly.

I was just driving and thinking about your issue. I've got BFG KO2 285's and they definitely make a rumble above 55 or so. And I started thinking that with the tires and wheels the size you have definitely gives more room for manufacturing errors and then if the balance shop doesn't put in much effort that could do it. I've also heard about tires with slightly warped belts that don't affect balance but do vibrate when driving. Doesn't match your symptoms though, I think ithat would be noticeable at all speeds and would increase with speed.

While I was chasing down my problem I stopped by a shop where I know the guys. One of them is an older guy and a real "car whisperer", although not an LC specialist. I described my vibration as starting right at 65mph, increases under acceleration, and after a few seconds it decreases when I let off the gas even if still over 65mph.

Shop owner shout out "wheel bearings" but the car whisperer whispered "what you just described is u-joints". I told him that I thought so too and told the shop owner that the front wheel bearings and races are brand new and the sound hasn't changed.

We put it on the lift and the mechanic went straight to the rear driveshaft u-joints. Pointed to the bottom of the caps and said "there you go". I didn't see anything, a little grease. He said that he sees wear and that's where it shows. I asked if it's enough to cause that vibration and he said definitely. There wasn't any play anywhere.

I replaced the front u-joints because they had been replaced by the previous owner and were obviously aftermarket. I had already looked at OEM and aftermarket joints and the difference in weight and quality was night and day. I assumed they could also lack the balance and durability of OEM so I just changed them out too. LC's really don't like aftermarket parts and I don't either.

My local dealer cost for new shafts was about $400 for the rear and $380 for the front, as opposed to $80 and $70 each for just the joints (x2). I enjoy the work but consider new shafts if you have to buy a bench vise, grinder, torque wrench, or if your shaft is otherwise worn/rusty or someone else has previously been in there and messed up the pressing or alignment. And also your time value.

Mine went quickly and easily. And rewardingly because it fixed the problem. Be sure to install them so that the grease fitting faces the right way, ie it's in the bigger opening. You'll see what I mean when you're there. Just make a note of it or take a pic during disassembly. Some people say to line it up with the yoke grease fitting but I put it opposite thinking about balance and the fact that no matter what it's position I should be able to get the grease gun on at least one every time I'm under there.

And be sure to mark the shaft for properly balanced reassembly.

It's a simple job but the details matter.

It's easy here on a forum to start throwing parts at a problem and miss. But this was my experience and I get so much from the collective knowledge here that I wanted to pass it along.