Jerk when accelerating from stop K2500 454 Suburban

[rodek]

Hi,

1999 K2500 454 4l80 NP246 autotrack
The truck is new to me and have been driving it for a few weeks.

Problem is that when accelerating from complete stop the truck jerks.
It almost feel like it's trying to start in 2nd gear and immediately changing to 1st.

I've been wondering whether it is transmission related or driveline / transfer case related?
I found out that there has been a recall with the driveshaft slip yoke that caused binding.
Also that the 4l80 could actualy be starting in 2nd.

Anyone had similiar symptoms?

 

[RichLo]

could be a u-joint starting to fail

 

[rodek]

I'll check the joints.
Also found some info to try changing tranny to manual low (1) in stead of D and see if that changes the jerk when taking off after coming to a stop.

 

[Mangonesailor]

I'll check the joints.
Also found some info to try changing tranny to manual low (1) in stead of D and see if that changes the jerk when taking off after coming to a stop.

+1 on that. Its what I would do.

Do you hear any audible noises? Pops? Clicks? Pings? Feel it in the seat?

 

[rodek]

No audible noise when driving, maybe a slight clunk when taking off.
There's just this definite feel of jerk or sudden jolt when taking off after coasting or braking to stop (red lights).

After touching the accelerator pedal it feels sluggish for 1/2 sec and then you feel the truck leap forward and accelerating ok.
Almost feels like something is stuck or tranny in 2nd gear and immediately shifting to first.
Rear brake shoes?

I'll try changing to manual 1 and see what happens tomorrow.
Thanks for your input!

 

[Mangonesailor]

No audible noise when driving, maybe a slight clunk when taking off.
There's just this definite feel of jerk or sudden jolt when taking off after coasting or braking to stop (red lights).

After touching the accelerator pedal it feels sluggish for 1/2 sec and then you feel the truck leap forward and accelerating ok.
Almost feels like something is stuck or tranny in 2nd gear and immediately shifting to first.
Rear brake shoes?

I'll try changing to manual 1 and see what happens tomorrow.
Thanks for your input!

Might wanna check the E-brake cables when you get a chance too.

 

[99'Subourbon]

No audible noise when driving, maybe a slight clunk when taking off.
There's just this definite feel of jerk or sudden jolt when taking off after coasting or braking to stop (red lights).

After touching the accelerator pedal it feels sluggish for 1/2 sec and then you feel the truck leap forward and accelerating ok.
Almost feels like something is stuck or tranny in 2nd gear and immediately shifting to first.
Rear brake shoes?

I'll try changing to manual 1 and see what happens tomorrow.
Thanks for your input!

A jerk(slight)/clang on take off is pretty normal on our trucks with a 6" lift - are you lifted?

 

[df2x4]

http://www.gmt400.com/threads/heres-your-fix-for-the-tahoe-yukon-driveline-clunk.30421/

Might want to give this thread a read. Not sure if it applies to the Suburbans as well but I would assume it certainly could. I wouldn't be happy with any kind of a weird take off personally.

 

[rodek]

Yep, that's the thread df2x2 I stumbled upon and got the slip yoke idea.
good info there thanks!

99 Bourbon, no big lift there (yet).
Previous owner has installed 1,5" block to the rear and had it cranked 2-1/4" in the front.
With full tank it was like a pogo stick especially with shot front end joints.
I lowered it in the front to about 1" crank and it's already a lot better.

I'll get back to this today when I have a chance to drive the truck a little.

 

[rodek]

Well, no change whether taking off in D or in 1st.
Tranny doesn't even change gears when selecting manual 1st after coasting/braking to a stop so I assume its already in 1st gear as it should.
Same jerk with manual 1st and D still persists.

Actually after some testing it feels like it could be the brake shoes binding and letting go or the slip yoke problem.
Also thought about the large tires, Subu has 34,5" tires and apparently no ECM calibration for that.

I'll be tearing down the front suspension and will redo brakes in the front and back too, we'll see what we'll find.