Question for resident GM techs
Its been a long time since i have posted here. but i know this is where i can call on factory info. i own a 2009 4.8 SCSB chevy with 4.10 gears and some mods. my transmission has been "rebuilt" twice under warranty. i have a tune on it from LSXpowersports. the first trans Dale tuned and it lasted 30,000 miles. the next LSX did and it lasted about the same. well now that im on my third go around still running the LSX tune, which i love, i feel like my truck drives different after the last rebuild. it's only been about 3000 miles and it has eventually gotten back to its old habits of rapping way out in 1st gear, every once in a while it shift harshly under moderate throttle. on the highway now it can't seem to pull it's weight up the hills, when in cruise it will lock 4th gear out for EVER it seems till i turn cruise off and force it to shift into over drive. even after it is over the hill and on flat ground for a long period. but my main concern today is i had to slow down on the highway today and then accelerate and my truck jumped rpms like 5000 and held them forever like ii was slipping i eventually let out then it went back to normal. my question is that i've never felt like GM warranty really allows a true rebuild like they only replace the bad and broke and reinstall the remaining parts. like my torque converter and misc things. is that true? my truck may be a 4.8 but god it's turned into a dog. any advise or knowledge would be great. i hate to take off all my stuff like my moderate lift and 285s but if i have to i will to have something i am capable of driving with confidence.
