Hey Mike, sounds like your expert....If you could be so kind to answer a couple questions. #1... I just bought a 2004 with 25000k on it. The first thing I noticed is some slop when driving along, letting off the throttle to slow for whatever reason, then hitting the throttle to resume and feeling the split second pause before it grabing with a cluck. I've noticed a few other people mentioning this.
If you apply the trottle easy, its not real noticeable.

#2...My second is in t/h mode going up a grade it will get real loud at times for a few minutes, like the fan clucth has locked and then smooth out an and go back to normal. Is this normal.

#3 My third is going down a steep grade, I touched the brake and it activated the down shift like it should, slowed a bit and I touched the brake again and it down shifted again. Then the grade lessoned a bit and I applyed the thottle to contiue and it UP shifted real aggressively and hard. That does,nt sound right to me....

Please give me some guideness as I,m completely new to all of this......Thanks so much......Kevin

No Modifications and I just serviced the tranny.
Does the converter slip often in the allison

I'll take a stab at it.

#1 There is another post about this problem. It's only a week or less old IIRC.
#2 When going up the grade are you towing and is the temp. hot outside? It's normal for the fan to engage while climbing a hill to help prevent overheating.
#3 Is this with Tow/Haul on? If so mine does the same thing even unloaded. The aggressive shift could be the tranny isn't used to this use and needs to learn.

The converter will slip until it locks.

alsup1955

1. When you let off the throttle at cruising speeds, the converter clutch releases and when you apply throttle, depending on speed, the Ally will engage with the converter clutch re-applying a second or so later. I believe this is what you are experiencing. Normal
2.Fan clutch is known for coming on at weird times under load. There is no control for this and we will have to trust GM to know best on this one. Also normal.
3.Under certain converter clutch strategys in the TCM, the converter clutch will not release, or will apply again after down shift occured and you may not have noticed the re-apply. Then your upshift occurs after truck is no longer under load and the converter was applyed while the upshift took place. Your upshift will be much more firm with converter still locked because you did not have the torque multiplication ( slippage in the converter) to cushion the shift. Again normal. I hope you understood this , and if you don't, call me and we will go over it again.
mike

Hey Laking slayer and Mike L
Thanks so much for the info. I was acually freaking out alittle about this, I guess because I'm ignorant. But you learn by asking questions.. And I hope you guys won't mind, because I'm sure it won't be the last question....Thanks again for your KNOWLEDGE......................................... ..........

alsup1955, You aren't ignorant. These diesel's and transmissions are complex machines and have a lot of engineering involved getting them to work. Definately ask questions and do some digging in this site for info as well. There has been a lot of things talked about here and there is a huge amount of information here. Also there are some very smart people here as well. If they minded people asking questions I would have been kicked out of here a long time ago. Good luck and enjoy the truck.