Has anyone running the 4L60 4 speed automatic tranny... every hear a "slap" sound when you first fire the truck up and start driving.

On my 09 chevy pickup, it does this sometimes but it's only right when I start it up and only with it's first shift from 1st to 2nd and it'll do it whether it's cold, or even if it's fully warmed up and I stop somewhere and come back out and drive off... it'll do it again.

It doesn't seem to hurt anything and the shifting is normal... I was just curious if anyone has run across this and knew what it was and if anything could be / should be done about it.

 

Check your engine mounts... Especially the driver side, they like to break, personally think the heat shield they started using on them did more harm to the mounts than good!! You 2 or 4 wheel drive??? Could also be yoke needing to be lubed if its 2wd...

 

That's all good. It really sounds like something from inside the tranny or possibly the torque converter.

 

Converter bolts loose maybe??

 

Check to see if your flex plate is cracked.