Hello everyone, first post! I need some guidance, input on whether to purchase HPT for transmission tuning on a 2015 Sierra Denali 6.2 8sd. I bought the truck knowing of trans issues, but didn't know the hard downshifts were so bad...I was in a coasting situation about 30mph, gave gas to pass, hesitation, then it downshifted hard, like there should have been trans fluid on the road. This super hard downshift is rare, most of the time I get a double clunk and go on. I've done a new trans filter and new blue label fluid job, not much help.
My question...Can the HPT or any other tuner help the 8L90 trans with shifting issues? I've been reading and youtubing all I can, seeing how changing mph numbers in upshift and downshift could help. I don't mind investing in a tuner, and putting is the time to learn how to use it correctly, but I would like to know if there is light at the end of the tunnel. Would like to keep the truck, but trading off is my other option. I've done the "D" tuner, firm shifts not any help, 87 octane canned tune, AFM off, about all from it.
Thanks for your time, look forward to hearing your input,
Alan