2007chevy5.3l

iTrader: (21)

Noticed this happen 3 times in the past few days.
Leaving from a dead stop under moderate throttle (almost half) the truck starts rolling and all of a sudden I feel a light bump, kind like someone taps your bumper very very lightly. I cant figure out if its the torque converter, driveshaft or the differential (no g80). Checked the trans fluid, which was just changed maybe 500miles ago, level is perfect and smells good, trans temp also is normal. Overall performance of the trans is solid, never had any hiccups before.

Maybe its nothing but its left me puzzled and id like to know what it may be.

Any ideas??

FLT

iTrader: (1)

The only thing that comes to mind is you might be having a wrong gear start due to a clutch or band being applied when it should not be. This could be an issue with a cracked plastic 1-2 accumulator piston or s sticky valve body. Vince

built408

iTrader: (10)

Sounds like the yoke is binding on the output shaft. Take the driveshaft off, clean the splines on the yoke and lube it with transgel or some type of grease. It will go away for awhile, replacing the yoke is a more permanet fix.

2007chevy5.3l

iTrader: (21)

Replacing the accumulator pistons are on the list. This does sound like it may be the problem.

2007chevy5.3l

iTrader: (21)

Wouldnt a bind be more abrupt or cause a harsher bump? I will take a look at this tho

built408

iTrader: (10)

I lube/replace yokes on about 5-10 nnbs a week for the exact same condition your describing.

53bowtie

iTrader: (6)

My dads 2000 GMC would be in second when he would take off from a light and would then clunk into first after rolling a ways. It was the shift solenoid and since there are two of them he just replaced them both. They are not hard to get to right on the end of the valve body. From what I hear this is a pretty common problem with the 4l60's (dealership stocks a bunch) and it may be what your in the beginning stages of.

2007chevy5.3l

iTrader: (21)

Well I think what im gonna do is install a stalled torque converter(been wanting one for awhile now), replace the plastic accumulators with the alum pistons, and lube the yokes while everything is out. Then if the problem still exists then I will look at the shift solenoid.

dlt76028

iTrader: (13)

It's that heavy foot in a heavy tahoe. Trans=