Driveline Question, something aint right...

[frito-bandito]

I have a 98 ECSB with the Vortec 305 and 4L60E trans and 10 bolt rear. I am starting to notice at stoplights and such, that when I hit the gas to take off, I feel a jerk. You know, the type of jerk that normally you'd hear a clunk to go with it, but I'm not hearing anything when this happens.
It feels like when you go to take off and hit the gas there's nothing for a split second then you feel a jerk and the truck starts moving.

I don't know if its my trans (works fine in every other way), or my u joints, or my rearend. How would I check my rearend for slack with out taking it apart?

Turns out my problem was kinda hard to describe, so I hope it makes sense, if anyone knows what could be causing this please let me know, thanks.

 

[barebones 1500]

everything you said makes sense but think it is in the tranny.if it starts off the line kinda slow when it does move then i think 1st is gone and it is jumping to 2nd. or just not engageing. i hope it is something cheaper and easier though. as far as checking the rear end for slack you could jack up the back and twist the driveshaft while haveing a buddy hold the tire and see how far it twists before the tire turns. this is not very accurate though but it is all i got on that matter.

 

[frito-bandito]

Well it starts of at a decent speed and it does have 1st, but I am still worried that it might be the tranny, I'm gonna check my u joints, tranny mount, and the rearend the best I can tomorrow. Hopefully it ain't the tranny...

 

[barebones 1500]

i hope it is not either. if it gets off the line fine then might not be the tranny. it was just the first thing that came to me and made the most sense to me cause i think everything else would have made that clunk that you werent getting

 

[Fleeingpepper]

Motor mount? In my old Cutlass it jerked after a second after pushing the gas to take off and it was a bad motor mount. Or tranny mount. Probably the tranny mount.

 

[frito-bandito]

Well guys, could my carrier bearing assembly cause this problem. I crawled under the truck this morning and checked to see if I could tell if my u joints are worn or not, when I tried to move the driveshaft by hand, I noticed that there is some play in the carrier bearing assembly like the rubber piece in there is kinda rotted or something. There wasn't much play by hand, but wouldn't there be more when the truck is taking off?

I also rocked the the truck back and forth in park and noticed that it looked like the leaf springs allowed to the rearend to tilt up and down with the movement of the truck, is this normal? Thanks.