2000 gmc hard shifting as trans warms up

[nucklebust]

u7198, ?, 2000 gmc k2500 6.0L.
I have a problem with the trans shifting good when trans is cold and as the trans warms up at around 100' the shifts get harder and continue to get harder as the temp goes up. This happens only with the 87 oct or performance tune. Does not with factory tune and/or with mods on factory tune. I need the performance for pulling 18,000 lbs but can not have the hard, neck cracking, drive line breaking hard shifts. The trans is a 4L80E that is a fresh rebuild less than two thousand miles. This problem was there before the rebuild also. I have tried to soften the shifts in the tune mods with no success. Trans temp towing run 150' to 200'. This problem happens on all shifts and all throttle %. I need a fix for this problem. Any help greatly appreciated.

Thanks Ken

[mikel]

Revision....?

[nucklebust]

Revision 2.13. I have a new problem also. I tried to change gear ratio from 4.10 to 4.88 and the speedo maxes out and the speed showing on the predator is 159 thats at idle in reverse barely moveing. I tried twice same results. I am currently running factory tune.

Ken Wilson
720-331-7057

[mikel]

OK, post a copy of the tune here and we'll fix the shifting and the speedo for you.

[nucklebust]

OK I am new at this, what does do not pm , post up first mean or is that what put on all your replies. I thought I was postting to the general forum. I want to run the performance 93 tune thats on the predator with 4.88 gear ratio. I think you want me to down load that tune to my computer and post it on this forum?

Thanks Ken

[06MonteSS]

that PM/Post Up thing is part of his signature... don't worry about that, it's in all his replies.. you're in the right spot..

and yes, download a copy of the tune to your PC and then post it up here on the forum...