today i just got back from a weekend trip in my 89 silverado and went to move my 03 8100 and no start the battery was dead which is strange because its only 7 months old and iv left the truck sit for a week and never had a problem well i jumped it with my 89 and it started and died then i cranked it some more and got it to start but only with some foot pedal help and it would have definately died had i not been given it some gas it settled out of that in a bit then when you would rev it up some but on the way back down it falls to like 200 rpms then speeds back up to about 750 this makes it very hard to shift gears smoothly and ideas

today i just got back from a weekend trip in my 89 silverado and went to move my 03 8100 and no start the battery was dead which is strange because its only 7 months old and iv left the truck sit for a week and never had a problem well i jumped it with my 89 and it started and died then i cranked it some more and got it to start but only with some foot pedal help and it would have definately died had i not been given it some gas it settled out of that in a bit then when you would rev it up some but on the way back down it falls to like 200 rpms then speeds back up to about 750 this makes it very hard to shift gears smoothly and ideas
Sounds to me like its definetly something electrical. Bad alternator is what it souds like. The Allisons have a hard time shifting with low electric current and low batteries. My alternator went out on my 8.1 and it wouldn't even go in gear and barley idle

Bad gas or filter? Check air intake filter. When the last time you drove it? Need more info...fill out your signature. ;)

last drove it the friday before i left and got back on sunday it did it once b4 and it was a loose battery connection but they are clean and tight now

I say charge the battery and disconnect and reconnect battery. It may have run rough due to low voltage to the many different modules. As to why the drain on sure unless battery is bad.

Brian

Did you check your battery with a meter, was it actually low on voltage? I have a new battery which is only about one year old, and on sat. I went to start mine and turned my key forward to run position and I had nothing, gauges didn't even light up. Turned it back to off, then back to run, and it I was getting very little power to the cluster. With in it that position with little power to the cluster, got meter out and checked battery, and found it at 12.7volts. Turned key off and wiggled cables, both were tight, but tried again and everything powered up and engine started. Pulled both cables all the way off. Negitive looked good, positive looked good at first glance, but did notice that the threads did have a little rust look to it. And the two matting surfaces of the battery and cable where it is the flat surfaces did also have a little rust look to them. Did a resistance check from the cable to the rust areas and it had very high resistance. Cleaned all the rust areas with wire brush and tested many times now with no problems. The rust was so minimal, that I would never had guessed it would have caused a problem because it still had 80% of the surface with good contact.

I had this happen on mine, everything went dead, bad idle, no gear, then died. I thought it was the alternator, so went and got a new one, installed it, jumped it, ran great. Little did I know that when I was messing with everything, i jiggled a wire back and it was connected. A few days later, same problem, and I thought it was another bad alternator. Got to looking and the B+ power cord was loose in side the little red box. Turned out this was the ENTIRE problem in the first place, so now I have an extra alternator, works great.....hey, if it is your alternator, you're welcome to that extra for CHEAP!!

well i took it to chevrolet today to get some warranty work done on the radio we will see what they come up with

Low voltage is the problem......I left my radio on a few times doing odd end stuff and run the battery down, when I went to start it the "Reduced Power" flashed across the display, check engine light was on and it idled like crap..try to give it a little throttle and nothing. It also does this on really cold mornings -0+. Mine came out of it once the battery was charged and the system relearned.......