I have mcrats race tune on a lly with a 8'' lift, 35" tires, and 3.73 gears. Has anyone had this same setup, and had problems with the shifting?
I dont kno if it has to do with changing shift points, fueling issues, or somethin else. Im sure its somthin simple but im not good with computers in general. It seems to shift to early into forth and fifth. From a stop easing into about half throttle, first to second seems like alot of defueling, like ur head comes forward before it grabs second. Second to third feels like a great shift. You go from being pushed back to being pushed back even more, and its real quick an smooth. So after that beautiful shift it hits forth and pretty much falls flat on its face. At that point i give it a little more gas to pick it up, and it'll sort of bog down until it grabs third again, than it takes off like a bat outa hell, then upshifts and falls on its face again. On the flats its not as bad, but on a long hill where you cant just pin it, its third to forth, forth to third. back and forth. fifth just feels kinda bogged down like forth, and one thing i noticed is in the mornin, before it warms up and its in a opened or closed loop "which ever it is" it doesnt feel so bogged down, and it seems to hld shifts longer. Ive been goin thru this efi live the last couple days so im kinnda figurin it out. Any Ideas? or, anyone else been through this one http://www.duramaxdiesels.com/forum/images/smilies/smile.gif
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Sounds like the usual stock trans issue's with bigger tunes. Try doing a live log with the scan tool and tuning tool loaded and watch the highlighted boxes and see whats going on different when its cold and hot then let us know. Not trying to be the bearer of bad news but if your not careful playing to much with big tunes a built trans will be in the near future.

i have heard that a new fuel filter can fix some shift problems...also you may need a lift pump if thats a really big tune

do you have a trans tune in? when i first put my trans tune in, my tcm rpm limiter was enabled on the ecm tune and it would hang between gears. also, fine tune the speedo. the speed has to match the rpm iv had to do that to a truck before for smoother shfits

have you contacted McRat, he would be the one to help you