So regardless whether I'm pulling the 1000lb 4x8 WellsCargo trailer or the 3500lb Monterey boat, I get this "bucking" during light acceleration and when at speed (45-65 mph). I'm concerned it will eventually destroy the tranny..

Can't seem to get a reliable opinion around town.

I added a key to the receiver/hitch to eliminate the clunking so at least that noise went away.

Weight distribution?

Fly by wire gas pedal need adjustment?

What could be the prob, thoughts?

Also, previous owner cranked the torsion bars to the max and the ride is wash boarded when I go over bumps/cracks in the road. Need an updated opinion on how to get a softer/safer ride.

Toyo AT Open Country 285/75/16's
Stock shocks @ 76k miles

Thanks

 

turn back your t bars to 23'' 1/4 from center of wheel to bottom of the fender edge. and when towing are you in 3rd or drive.

 

Thanks for the reply.

1) I just measured/discovered the center of wheel to bottom fender edge is currently 22". hmm.. (I was told by the alignment guy that the t bars were cranked to max - how could this be?)

2) Towing 101: Never, ever put the tranny in Drive.

Once again, I have the original OEM shocks (with nearly dry rotted bushings), Odometer 76k, New Toyos and I get washboarded over cracks/bumps in the road.

I'm thinking maybe I've got a shock problem that's a contributing factor?

 

Ya the shocks should make a big difference, Im running the bilstine shocks much better then the stock shocks.

 

What alignment guys know about Hummer T Bars could not fill a thimble.

Shocks could be a small contributor. What is the tire pressure you are running on that rice rubber?

Also keep in mind you are towing with a short wheelbase vehicle, you will feel some rocking chair and more so where the road has poor slab joints.

The old tow in 3rd instead of drive..... is an urban myth IMHO. It just stops lock up and builds heat. Moving out of lock up (faux overdrive) is caused by heavy load and designed to work that way. Happens when not towing on long or steep hills as well. Once it kicks out of lock up, it is doing nothing different that running in 3rd, but if you tow in 3rd, it will never run in lock up on level or down hill stretches because you have forced it to churn in 3rd.

Per the manual: "If you have an automatic transmission, you can tow
in DRIVE (D). You may want to shift the transmission to THIRD (3) or, if necessary, a lower gear if the transmission shifts too often under
heavy loads and/or hilly conditions."

 

Thank you for the update on trailering in Drive. The shorter wheelbase does tend to add some rocking, but with the washboarding it's a hard ride.

And yes, alignment "specialists", a reputable transmission shop, trailer salesmen and hitch installers all gave different answers or had no explanation at all. hmph. I know I can keep prospecting. Anyways, I'm here because we all got one to play with. I've had an inspection and alignment in February and another inspection a few weeks ago. All said the suspension is "fine".

Stiffer Suspension
This H3 also has the locking rear diff (which I'll use in August when the boat ramp gets real slimy), but I think it still runs the 4:56 gears? Does having the rear diff lock mean it has the beefed up/stiffer suspension?

Tire Pressure
44 psi (the tires recommend 60 psi cold)

 

The "off road" suspension (Adventure or Lux/Off Road -with locking diff.) is the exact same suspension as every other model H3, except the shocks have a larger diameter piston and slightly firmer valving. Difference is fairly minimal.

IMHO, your tires are over inflated, that's what I figured, but I thought I would ask first. I do believe you are confusing weight load at MAX inflation... ie. 60 PSI. Anything over 40 PSI in a 33" tire, I do not care who makes it, is going to make your ride suffer, cause the wash boarding effect, and contribute to your bucking sensation.

In and about town I usually run my 305 (33") MTZs at 38 PSI, which is pretty much the consensus minimum PSI to avoid TPMS false alarm issues. If I am going on a road trip, I bump it to 40 PSI just to help with MPG, and that is plenty stiff. Take a look at your door jam sticker for tire inflation info for your old stock 33s.

May I suggest you try 40 PSI and see what you think and please let us know.

 

I'll give 38psi a try. recommended OEM tire inflation is 35psi.

A doubletake shows recommended Toyo inflation at 80 psi cold (with no other psi info on the tire). I don't quite understand this. I'd think Phoenix in the summertime would grenade this tire at 80.

UPDATE:

PSI at 39, entirely different ride. Much smoother, diminished bucking. Adjusted trailer tires to 35 psi (trailer is currently empty) and everything got even better. Left the rig in Drive, and at 70mph on the freeway I kinda forgot I had a trailer.

Many thanks, Doc.

 

Not sure you have considered this but proper adjustment of the tongue weight on the trailer significantly affects the ride. Trailer tongue weight should be 9-15% of the total trailer weight. You can adjust this by repositioning the trailer load more forward or more behind the trailer axle.

How Tongue Weight Works - HowStuffWorks