I was bored and building my self a '05 Dura on the chevy website and I noticed that there are HP/TQ differences between the manual 6 speed and the allison. Can someone tell me why? I am a Cummins fan/owner and I do not know much about the Duramax's but I'd liek to learn more.... This is my first post over here by the way....:ro) Thanks guys. If this is in teh wrong sections mods, do your thing:cool2:

Can't help you with the difference in HP/torque, but I do have to agree about this site vs others. I was reading over at the Dieselstop and it didn't seem to be too friendly. Post your topic in the wrong place and they jump all over you and delete your posts. The Diesel Place rocks!!!

:offtopic: Yea I like the attitude over here alot. Nice folks. I only read the Diesel stop to read all the issues with the POS PSD's. :muahaha:

The allison is capable of handling more power than the ZF-6 tranny. With the auto power is lowered to 520 lbft in 1st and 5th gear and you get the whole 605 in 2-4. BTW has anyone else noticed how much bigger the torque converter is with the lly compared to the lb7?

So it basically defuels it's self? Interesting. Thanks Vegas!!!!!!

It's a little more sophisticated than that. The Allison FAQ seems to indicate that the Duramax ECM and Allison TCM work together on torque as well as grade braking, cruise control, and accelerated warm up. I vaguely remember reading that it also backs off the torque just before and after each shift to minimize clutch pack wear.

http://www.allisontransmission.com/service/faq/index.jsp?CategoryID=11

The flywheel is the limiting factor with the 6 speed. GM uses a dual mass flywheel that absorbs vibration from the engine to keep noise levels down at idle and under hard pulling situations. The springs in the flywheel are not strong enough to hold the power so they compress completely and wear very fast causing flywheel failure eventually. I am running a solid flywheel and double disc clutch and the ZF will hold everything I have thrown at it.