Vibration between 62 and 65 mph (1 Viewer)

[Timber]

My 98 LC (4.7 V8) vibrates or shimmies -- just slightly -- between 62 and 65 mph. It has done this for at least three years, and it has continued to do it through numerous rebalanings, alignments, and two different sets and brands of tires. (I just changed to BFG AT KO 285/75-16, by the way.) It vibrates at the same mph interval whether I am gunning the engine or letting it coast thru that range with my foot off the pedal. You can feel it -- obviously -- and the brush guard visibly trembles . . . something that several of my buddies have pointed out while we were spinning along the interstate on out way to various hunting and fishing trips.
I have checked not only tire balance and alignment, but also the drive train.
I don't think it's dangerous to me or to the vehicle. It's just irritating as hell that I can't figure it out.
So -- after that long explanation -- have any of you 100 owners run into something like this before?
I would greatly appreciate any help or suggestions. (The dealer -- surprise -- is clueless.)
Best,
Mike

 

[Snook]

I had this same problem at that speed you mentioned. It goes away only when I disabled the overdrive at that speed.

The drivetrain must be the culpit where the gears or shaft's rpm do change during disabled overdrive while all other axles, wheels remained at constant speed and rpm.

Still, I can't put my finger on it.

 

[Pitbull]

Find a place that can balance all of the tires/wheels while they are on the LC. It worked for me when I have this type of a problem.

 

[Timber]

My tire installer told me that the ABS system would cause problems if they tried an on-the-vehicle balancing. Are they wrong? Is there a particular machine that works well with 100s?

 

[the shed guy]

Just drive at 61 or 66mph, problem solved

 

[Pitbull]

I had it done on a Acura NSX and a FZJ80 LC but it had ABS. Doesn't sound logical that it would be a problem to do it on a 100 series.

 

[Snook]

This interesting RV link below do mentioned "vibration/shimmy" at 62 mph. But it also vibrated at 32 mph in some case.

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/14072523/gotomsg/14073007.cfm

Mine do vibrated at 65 and 32 mph but very little, only noticeable on smooth roads, free from bumps and seams.

 

[ShottsUZJ100]

Hey Timber. Ever had your drive shafts checked for balance?

 

[Timber]

Hey Timber. Ever had your drive shafts checked for balance?

Didn't even know I could. (My experience as a mechanic is pretty much limited to the hours I spent juicing up an old 65 Chevy in high school.) No mechanic or shop I've ever spoken with has suggested balancing the drive shaft. What is the procedure?

 

[ShottsUZJ100]

Not sure. I needed it done to an old 4WD Mazda MPV I owned. If I remember though the faster I went the more vibration I got. If it's only at your one speed it may not be a drive shaft prob. Sorry about the lack of knowhow on this. J

 

[mabrodis]

Any driveshaft shop will balance it (and straighten it if needed)...just look in a phonebook or something to find one...

Driveshaft balancing could be the issue, it seem a bit doubtful but possible. I had my rear driveshaft rebalanced in my 80, I thought it might be vibrating (hell I can't tell what vibes come from what), but also I wacked it pretty hard on a rock and I think ripped a weight off. The shop straightened it (something like 0.050" out of round, which doesn't sound like much to me, but they said that was definetly enough to cause vibes)...cool part is when you get it back the shaft is all clean and repainted, new grease, etc, looks brand new...complete bill on mine was $40 IIRC...not alot I didn't think, hell I'd have paid them $20 just to clean it the way they did and painted it...looks really nice!

I would expect a driveshaft vibe to be there all the time, just get worse as you go faster, but compared to tires and other work, having the shaft checked is not expensive, just pain to pull out usually, and either drive with your center diff locked or just don't drive it until you get it back.

Good Luck...
Mark Brodis

 

[drewloch]

I had a vibration in my 2000 around that speed.
I was still under warranty and I took it to the dealership.
Turned out to be the Transfer case mounts were shot.
This was probably a side effect from when my tranny
went out and was replaced.

 

[the shed guy]

Or an overgreased front tailshaft slip joint.........

 

[Snook]

Drewloch,

What is your 2000's mileage?

You mean the transfer case 's mount, the rubber that hold the case were shot? Not internal parts such as gears & shafts.

 

[superdosser]

Road Force Balance

Find a place that has the Hunter Road Force Balance manchine. There has been tons of talk about vibrations on the Audi site I'm on too -- And 1/2 the problems can be fixed with this fancy balance machine. I'm not up on the tech part -- but many guys have had tires that balanced out fine on traditional machines but had vibrations. After the RFB all was fine. It's an easy/cheap first step before diving into the driveline....

 

[Timber]

Find a place that has the Hunter Road Force Balance manchine.

Found one, paid 'em eighty bucks, and the vibration still isn't fixed. But it IS much, much better, which shows that the problem is wheel-tire related. I'm guessing that I've got a wheel or two that are out of round.
For now, I'm thru spending money to run this down. I'll live with it until the next burst of energy.

 

[drewloch]

My 2000 only has 40,000 miles.

Yes, the rubber mounts which support the transfer case were shot, no internal parts. The dealership might have messed them up when they replaced my transmission though.

 

[superdosser]

More than wheels/tires perhaps...

A road Force test should have caught any wheel roundness issues. Could be a combo of wheels/tires and what you've got now is drive line related.

 

[Timber]

It worked!

Time to eat my words.
Now that a few days have passed since I had my tires balanced on a Hunter Road Force machine, guess what? Every bit of the vibration is gone. Why it wasn't gone immediately is beyond me. Maybe the truck had to settle in to the new tires, maybe I was feeling vibration from a loose skid plate that I found on Friday, or maybe my brain was still rattling from all those miles of vibration. But -- whatever the reason the Hunter Road Force didn't kill all the vibration right away -- the shimmy is now completely gone.
Thanks for the great advice.
Now my Cruiser is perfect. (At least, I think so.)