[shifty]

Originally Posted by WorkinLonghorn

Shifty, you didn't say if the fluid looked and smelled OK. That is the first step in a logical decision.

Good point, I'll drain some off and check this w/e.

Other details follow, if it helps?

Pretty sure my '03 Sierra had a 4l65e in it. Shifted way less clunky than this 4l60e. Clunky/late shifting is most of my gripe, similar to what rpmerf describes above.

I'm in the 12-18 month range owning this thing (my 5th GM truck now...) and rarely need to drive more than 10-15mi/day so only ~4k miles driven so far, it was enough to find and tackle a lot of the bigger cumulative problems. CarFax I ordered after purchase shows regular oil changes (3-5k miles) its whole life, but not much more.

At 3k miles I started working through 1st-round maintenance, lubes & flushes. Seafoamed the top-end & oil ~150mi before my 1st oil change. I was amazed, putting Seafoam in the oil killed all valvetrain chatter I'd been hearing. Swapped out the buzzing fuel pump while replacing a failed tank pressure sensor, also swapped the fuel filter, the truck starts instantly now and accelerates like it's brand new, but that helped expose the shifting issues.

Brake/Cooling/Tranny flush and filter change are coming up quickly in my list of crap to tackle. That led me to dig on recommendations for maintenance on the 4l60e and ... that when I saw all the warnings everywhere about flushing the fluids causing imminent death. Maybe I'm confusing "flush" with "change" and that's coloring my opinion.