2009 Chevrolet Avalanche 4wd 5.3 flex, automatic, 160000. Had the tranny rebuilt or repaired for some reason a few years ago, before I bought it. Previous owner towed a large trailer with it a lot.
Car shifts all gears nice and smoothly EXCEPT from 1st to 2nd. It clunks between 1 & 2 if I give it even light normal acceleration or higher. If I take it really easy it glides into 2nd OK, but if I want to accelerate normally so the person behind me at a stoplight doesn't get all bent about my grandma driving, it lurched into 2nd.
I found out quite by accident that if I put the vehicle in 4wd, it shifts really nicely from 1 to 2 and everything else... THEN, if I take it OUT of 4wd, back to 2wd, it shifts great...FOR A WHILE., perhaps a few miles, perhaps a day or two, but never very long. Eventually it goes back to the lurching rouch shift between 1st and 2nd again.
Anyone have any ideas what could be causing this?
Thank you all for your advice!
