BetMinesFaster

Hey all.

I have an 02 2500HD 8.1/Allison truck. Has SW Long tube headers, 3" True duals and a Custom HP tune and electric fans. 4:10 gears with a 265/75R16 tire. Transmission has a Transgo Jr. kit installed. The truck is maintained perfectly. My annoyance is that it lugs fairly hard on the 1-2 shift, I understand the ratio change fron 3:10 in first to 1:81 in 2nd is large but it just seems that with a fairly sturdy big block and 4:10 gears it wouldnt fall on its face quite so badly?

If anybody else has an 8.1/Allison and can tell me how yours feels that would be great!

Not sure if its something im missing or thats just how its going to be?

Thanks - Ryan

BetMinesFaster

Ill mount my helmet cam on the headrest and make a video and post it for reference!

Whippled 496

iTrader: (4)

Mine did the same thing until i got in there and pulled the TQ management out with EFILive. My original Westers tune years ago was supposed to have TQ Management removed but it wasnt.....at least not the way it should have been removed VIA several different tables within the ECM AND TCM. Your seeing a defuel and (more than likely) negative timing numbers during the 1-2 shift if all your TQ management is still there. Mine would go from 18* spark advance to -2* advance during the 1-2 shift when TQ management was still in control. You are going to say your sure its been removed....but I bet it isn't.

BetMinesFaster

The tune was done with HP Tuners, I was confident the TM was removed. On logging were not seeing timing pulled or fuel cutting?! Only found 1 table that looked related, canceling the torque signal between the TCM and PCM. Do you know what the other items are that need to be played wth? I know finding the method of eliminating the TM on this truck with a seperate TCM was not as straight forward as the LS/4L60-80-85 trucks. Any input would be great!

Thanks! Ryan

Kerr

rayn somethign isnt right.. does it do when you hammering it..

My 8.1 with the 4l80E shifted like a grandmaw we fixed with a lnk someone here posted. I dont have it at home, its saved on my office computer... ill post up tomarrow..

Anyway brad's 8.1L allison is stock except for tires. it had very week shift for many years. then the shift silonoid or severo something like that.? went out in the trans... had it replaced at the local shop with a newer version of the same part... it shift very firm now and if your carefull when it wet you get a nice sideways action going even driving normal when shifts

do you change the settings in the tow/ hall or just regular mode... if you didnt do both compair how it shift in tow vs no tow... we left my tow setting stock...