Vibration While Towing (1 Viewer)

[fishin]

I have a 99 Landcruiser. I am towing a 15 foot enclosed trailer (Single Axle) with two ATV's inside . My best guess is that this trailer and the ATV's weigh about 2200lbs. The Cruiser pulls it with no effort, however between 52mph and 58mph I have a vibration. I cannot figure out what is causing it. I thought that maybe I had a slipped belt in one of the trailer tires, so I put new tires on the trailer on Saturday and balanced the new tires and wheels. The bearings on the trailer have just been repacked, so no issue there. I pull the trailer with my father's Dodge Durango, no vibration. My cruiser is riding on Michelin LTX M/S tires that have about 25,000 miles on them. The truck had the tires rotated and "Road Force Balanced" at the Toyota dealer less than 6,000 miles ago. Please let me know your thoughts and what I can try. Right now I am driving 45 or 65 and trying to stay away from the middle.

Thanks,
Brett

 

[Bloodhound]

vibration question

Hi fishin, are you saying you had the vibration only while towing or that’s when you first notice. I ask because you mentioned you are now driving between 45 and 65. So is the vibration felt without towing also?
Is the vibration felt in the steering? Have you recently been stuck or rotate your tires since your last balance? I had a new set of tires put on and Road force balanced last year and they had marked my stem location for what ever reason but when I returned home my tires had rotated on the rim about 1 to 4 inches each. I don’t think the soap solution had evaporate before I left for a 40 mile errands and trip home. I had a vibration (60 mph) as you describe until I took my rig back and had the rebalance dry rim. The vibration never came back although I’m sure my tires have moved since then but no vibration. The vibration I felt was felt through the steering wheel. Might check your motor and transmission mounts as a suggestion.
Good luck

 

[fishin]

Bloodhound, thanks for the note. I do not have any vibration without the trailer hooked behind. I had the Road Force Balance done on dry wheels and tires...The tires had been on the truck when I purchased it, and had about 15,000 miles on them at the time that I did the Road Force Balance. Without the trailer the truck is silky smooth. The vibration is not felt in the steering, but in a shaking motion inside the truck. I have a heavy canvas bag that holds my different trailer hitch drawbars, recovery gear, shackles and straps. The vibration is enough to make the stuff in that bag rattle. I really am stumped on this one...

 

[wareagle]

FWIW, I just noticed that my TLC does the same thing at the same speeds. We loaded down it down with 2 adults, 3 kids, and a ton of luggage. We picked up a very mild vibe from about 60 to 70 MPH. This vibe is defintely increased w/ extra load and is limited to very specific speed ranges. Tires are new, so I think its a balancing issue.

 

[Jim_Chow]

Could it be from the weight of the trailer compressing the rear suspension and, as a result, the driveline angles change? My old 4runner does this at certain speeds (mostly when I just get into 5th gear ~ 50mph) w/ no towing. It used to do it even at 35mph until I added a 3 deg shim to the leaf pack.

 

[Adam R]

If you vehicle is sitting low in the rear when loaded, it is most likely the driveline angles. I had the same issue when I towed with a trailer in our LC.

My jeep had a similar problem when the rear end was loaded. I put in air bags to compensate for the additional load, and it ended the vibes. I adjust the bag pressure depending on what I'm carrying and it works great.

I'll be adding lift springs and air bags in the near future to our '99 for the same reason.

Adam R.

 

[Adam R]

If you vehicle is sitting low in the rear when loaded, it is most likely the driveline angles. I had the same issue when I towed with a trailer in our LC.

My jeep had a similar problem when the rear end was loaded. I put in air bags to compensate for the additional load, and it ended the vibes. I adjust the bag pressure depending on what I'm carrying and it works great.

I'll be adding lift springs and air bags in the near future to our '99 for the same reason.

Adam R.