Allison 6sp: Shifting question

CHYKYNLIPS

GA Diesel
Aug 22, 2009
103
0
0
When at full throttle, it feels like 3rd is lugging half way through the gear, then when it shifts up to 4th, it pulls strong again. I didnt have the monitor plugged up at the time so i dont know if it was 4th it shifted up to or if it was just the t/c locking in 3rd but my question is if it was any type of malfunction aside from just not being learned to full throttle shifts, would i have a code.

I installed a transgo jr myself almost a year ago and felt pretty good about the job, as far as everything being installed correctly and the reinstallation of the valve body going smooth. Im curious that if there was any issue that had anything to do with the transgo jr, wouldnt there be a code and wouldnt it be likely that the tranny would not even operate correctly under normal driving conditions? Under normal driving conditions, the transmission shifts smooth through all the gears and i have not had any codes.

I am hoping that a problem with the transgo jr would be obvious if anything was not right and i would have some code. If so, this may just be an issue of the transmission not being used to full throttle. I rarely accelerate hard in the truck and that is what leads me to hope there is no mechanical issue. Thanks guys.
 

Mike L.

Got Sheep?
Staff member
Vendor/Sponsor
Aug 12, 2006
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Fullerton CA
If you rarely drive it hard you are going to experience defuel when you jump on the throttle hard. Transgo jr is not enough with your programmer.
 

CHYKYNLIPS

GA Diesel
Aug 22, 2009
103
0
0
Ok. Thanks for the info. It stays on the 80 rwhp tune. I thought the transgo jr would help it hold an occasional full throttle at 80 rwhp but i guess that is about the limit on a stock 6 spd Allison. I guess the tcm sences a slip and tells the ecm to defuel?
 

CHYKYNLIPS

GA Diesel
Aug 22, 2009
103
0
0
I havent limped this truck before so do you think it is that the defuel is from the tcm senceing a slip or that the tcm makes the ecm defuel from seeing a sudden unusual spike in torque?
 

CHYKYNLIPS

GA Diesel
Aug 22, 2009
103
0
0
Ok, I see. I wish the canned tuners allowed the option to override that signal from the tcm. I realize that you could toast the tranny that way if the driver didnt care but i atleast wish it were an option. I dont use my truck in ways where i could benefit from all the offerings of EFI Live, but i know it can tune the tcm. That would be nice. Thanks for answering my questions.