I have a 96 2500 and it does the same thing pulling a trailer. I don't know why it does it either. If you find out please let me know. I'll look into it some and get back to you. Oh yeah mine does it in 4 wheel drive I don't know if that makes a difference.

 

mine was in 2wd... when i tow my motorcyle trailer it doesnt seem to do it.. but my dads heavy duty trailer it does. i really want to know why, it bugs me when my truck doest work 100% right

 

Sounds like the bands chattering in the trans, have you ever had them adjusted?

 

no i havnt had them adjusted and it doesnt seem liek it would be them.. its more of like the rear of the truck going up and down. this was a big trailer and i had a big lawn mower up towards the front of it. i was goign down the road to get the rest of the stuff till my buddy got there with his truck to pull it to where we were goin. could having all the weight in the front of the trailer and nothing in the back cause it? and what are the symptoms of the bands being in need of adjustment?

 

Sometimes, under heavy load, the bands wil chatter if they have some slack in there. Acting as if you are dumping and pushing in the clutch real fast, making the rearend torque up and down due to the huge power indifference. It is just one possiblilty.

 

ok thanks man ill get them checked

 

i figured it out, the tires on that trailer were nylon, and when the trailer sits for a whiel the tires get indentations in them.

 

Even more fun when its the truck doing it!

6yrs ago I got M/T Sportsman fronts and ET Streets for my 96(dot skinnies & slicks). Couple days after going to the track the first time I took her out. Barely got out of the driveway and probably doing 15mph and shes bouncing like crazy!! Im like WTF is goin on. Putted the 200' or so back home and called my parts guy. He laughs and says, its the tires you dummy. Give them a mile or so theyll round out again. Sure enough they did. Barely notice it now when it does happen the odd time, same with pulling the empty carhauler behind the V10.

 

It's called spring wrap. The springs are the only thing keeping your axle from spinning. Under heavy load, the springs end up springing not just vertically as they should, but they twist too. Unlike vertical movement, there is no shock absorber to damp this motion, so it just bounces. It's hell on your u-joints, and probably on the rest of the drivetrain.

There are two fixes; smoother driving, or drivetrain mods. The potential mods are horizontally-mounted shocks which absorb this motion, and/or traction bars. On some vehicles, traction bars can really make the handling/comfort turn to shit when the back is unloaded. There are traction bars you can quickly deactivate/remove, but they cost a lot more. Shocks in this situation have no effect on handling/comfort.