rob160

I recently purchased a truck, (2007 megacab, dually, 4x4, 5.9, 6 sp stn) it has a ton of power, compared to my last vehicles.

I have had the pucker factor increase substantialy a couple of times rolling down the highway at 60mph. When i tromped on the throttle to pass, my *** end of the truck gets mega shakes! the only I can do is release the throttle, no breaks, keep her straight, and let her slow on her own, until under 50 mph, once under 50 it calms right down. I obviously was concerned and pulled over, didn't see any damage. I have now had it happen 3 times. other than that, it runs straight, smooth, moves out really well, wheels are balanced (checked twice, now)

any ideas?.... on what is causing it? why?, how to fix?...... ifi it is wheel hop, i have seen some nasty pictures on the web of the damage that can occur

Rob

j-fox

Wheel hop in general is a condition where under power the rear axle twists or rotates opposite of the wheels, this is allowed by the leaf spring twisting, then when power or traction decreases the axle snaps back. This condition can continue until the spring unloads. It is not entirely due to leaf springs as I have seen it on GM cars from the 60's.
Traction bars can solve this. Usually though spring wrap up is worse when taking off from a stopped position.
Slapper bars were designed to control this.
There are several companies who make torque bars for this purpose.
Pinion angle can cause a similar feel. Never let the pinion angle go to 'zero'.

Travis_

XLR8R

Are you sure it isn't Death Wobble from the front axle?

AggieJustin

If you slowly accelerate to 60+ mph, do you get any shakes?

I would only expect axle wrap to last as long as you are on the skinny pedal. Once you lift off, any wrap would stop. You would not have to coast down to slower speed for it to subside.

Wondering if you might have loose/broken u-bolt on the rear or a broken retaining pin. Once it starts shaking, it needs some time to stop. But it only happens when you quickly load up the suspension (like hard acceleration).

tool

Sure sounds like death wobble to me.

Ive yet to have it on the 06 but I know the first time it happened on the '99 it was SCARY!

Do you feel the steering wheel jerk back and forth? Almost feels like the wheels are falling off?

Floridacracker

maybe u have flat spots on the tires from a lock up
my last truck would shake some times
try doin a burn out to make them more round

rob160

not a front wheel wobble- steering wheel is straight, 4x4 ing in muck, sand, gravel has not been an issue up front. it has only happend when I go out to pass, am left in passing lane, off power waiting for it to calm down wheels straight, while the vehicles i just passed go by in right hand lane...... looking at the crazy hopping *** end of my truck until i slow enough for it to stop.... maybe slappers are needed?..... still need to dyno this thing! find out exactly what under the hood!

Travis_

Sounds like a balancing issue. Does it go away if you were to go faster? Also does it happen under hard acceleration or light acceleration.

pupeperson

Maybe your oem shocks are even worse than most....

XLR8R

Traction bars are always an improvement, but your truck must either have something loose or out of balance in the rear.