When accelerating hard onto the freeway, the front end of my truck begins to bounce. Any ideas what's causing this? If I back off the throttle, then it stops. Only there on occasion under heavy acceleration.

The shocks are KYB MonoMax and only have about 25K on them.

 

Nobody???

 

my first guess was the shocks, if you have the time i would take them off and see if they are performing the way they should.

 

Forgot to mention, I just had it aligned and the shop said everything looked fine. Shocks? I hope not!

 

Piper--

You say this is only under hard acceleration? Can you reproduce the "bouncing" by driving on a rough road or doing anything other than accelerating hard?

If ONLY under hard acceleration, then it's not the shocks.

 

Only noticeable under hard acceleration ... I'm stumped! Guess I just got to stay off the skinny pedal!

 

I have something similar, but i am unsure what it is, I just had my driveshaft balanced, and put in new universals. It is still there, I am getting new rims and tires soon, might be that, could be out of balance. But it stops as soon as I take my foot off the gas. Will let you know soon.

 

Check the tranny fluid, I was reading through my manual, and it said that if the tranny is low, the TC might shutter, I am going to check mine in the morning, installing new EBC rotors and pads.

 

Does it only happen under hard acceration getting onth the freeway or also hard acceration on ANY road? I'm thinking the torque converter is slipping; well, locking and releasing, locking and releasing, locking and realeasing. All really fast like causing your truck to pogo or bounce.

 

This is interesting, my truck does the same thing when I'm gettin on it to accelerate. I've been stumped on the problem as well..

 

Bad motor mounts will cause any vehicles front end to shake/bounce/vibrate when accellerating, especially under load.

 

Okay, I suspect I might know why ... I run balance beads in the tires. Do you think the hard acceleration might cause the tires to be unbalanced until the beads distribute properly?

 

could very well do it. but usually then it would always happen at a certain speed, I would think. Does the bounce happen at a particular speed? I checked my tranny fluid level, it was good, and red. So its not that for me.

The motor mounts, could also be a problem, That was my next thing I was going to check.

 

As I said, it only happens on hard acceleration getting onto the freeway ... usually when pulling away from those controlled onramps, here in CA. Gotta leave grandma behind in a nice black cloud or I'd never get anywhere.

 

I think that I recognize you from the fishing/boating message boards.
When I used to tow my boat with an Astro van, the trans would shutter while taking off which made the front end shake a little. So, maybe you trans is slipping under heavy load.
If interested, I have a set of rims and tires that you can try to eliminate the tires.
I'm over in Torrance
PM me if interested

Scott