Takeoff
 

i have an 03 duramax..about 130 thousand on it..
and when i go up the corner and then go to take off it kinda jumps??
i think its the vacume booster...any thoughts?

What exactly do you mean by, "Go up the corner"? Can you be a little more specific? Also, can you fill out your SIG so that the members here can know more about the truck and if you have mods or not, etc...:U:

You don't have a vacume booster.

Do you have any type of surging at idle?

describe "up the corner" a little better so we know what ur talkin about:humm:

is it the front or back that jumps?

Good call there. I think someone already asked that. :tttt:

if i go up the corner and make a complete stop..and then take off the rear end jumps..
thats wat i mean

up to the corner? (like to the stop sign and then off again?)
sound like a busted leaf spring or shock, maybe a mount causing it to rotate or "Bounce" under load.
I could be wrong though...:w2:

u sure ur not hitting the curb :tttt:

yeah when i take off from a stop sign...
it mite be the something with the suspension like u said..
because when i have the gooseneck trailer hooked on it doesnt do it??

hhhhmmmmm....
 

:humm::humm::humm::humm:

:humm:

It sounds like what you are experiencing is more than what I had. That last split second before the truck completely stopped I would feel a small bump in the driveline. Right as I let off of the brake I would feel the same. The dealer removed the rear driveshaft and greased the output shaft on the tranny and the driveshaft. There is slack in it. On some models and years there was a recall on the output yoke (4X4) to replace them with a different design. It might be worth asking your dealer if yours is included in that.

In all honesty though it sounds like you are experiencing something more significant.

I was thinking that too, but the clunk isnt that bas as he is describing it.

G80 staying locked and hopping around the corner???

mine has...
 

now mine has done that a few times, but not recently, whenever it has I just changed the fluid in the rear...
what else causes that?

Does it do this when taking off from a stop sign and going straight? It feels like the back end is kind of slightly hopping up and down until you get to about 15-20 mph?

Do you have a 2 piece driveshaft? The CC, LB trucks came with them. I think the EC, LB trucks did too but can't remember. I've only seen the CC, LB.

This sounds like launch shudder to me. It won't do it when loaded because the trailer is squatting the rear end and changing the pinion angle.

I played with a few of these when I was at the dealership. You can shim your carrier bearing down and it will stop the launch shudder when you're empty. The only problem is that it can create a vibration at a different speed. For instance, one we did cured the launch shudder but created a new vibration at 80 mph. This wasn't acceptable to this customer because he did most of his driving at 80 and rarely towed. It took some time but we kind of got the best of both world eventually by playing with material thickness.

GM even had us experimenting with 1 piece driveshafts for a while but that went away.

My advice is that, if this is launch shudder, then you need to make a decision. If you tow more than you run empty then just leave it the way it is. It really doesn't hurt your truck.

If you run empty more and this really bugs you then you're in for some work and experimenting trying to shim your carrier.

EC LB dont :)

my rear end kinda hops when i turn real sharp in 4x4 nice and slow, the wheels kinda lock

mine too
 

that is what it sound like mine does....:w2: