lookin for some guidance from you guys that have been street pulling south farther with 600+ hp have a 05 qc sb auto. Im lookin to make 700+ next summer but dont think i have the right truck. want to at least have a QC long box,but debate auto vs 6spd,this is the next thing-had a nv5600 and loved it now miss it, but is the g56 6spd any good at all for this abuse. have a hunch its not. i know the billit auto is better to drive all around but the stiff clutch on the manual would suck on the road. anything thats a advantage over those **** high dollar duramaxs is good (besides the cummins)!! thanks luke

 

I know most good truck pullers swear by the manual and you cant beat the stock strength of the NV5600. Well I have to say I swear by my auto

I have a 99 3500 QC 3.55 gear, last dynoed 572 on diesel and 649 on nos, I have pulled with a larger set of injectors and double the nos shot, it was very strong my competitors said it looked like well over 700. I intend to find out what a well built auto can handle.

my tranny is a full billet DTT, after about 10 pulls I sheared off the billet intermediate shaft which DTT replaced and went through the tranny again for free ( I like to deal with people who will stand behind there product ).

I have since started using TRE diesel performance in VA who is a DTT rep ( and is a transmission wizard ) I have pulled against some very awesome manual trucks including 07 DHRA Super Street Champ Robert Miller and his wife Faith, the have the two baddest diesel trucks I have ever been near(very impressive to watch pull).
they have all said repeatedly they have never seen an automatic truck pull this good ( maybe everyone just wants to be there to see if the thing is going to fly apart ) but so far I wouldn't even consider switching to a manual and I also have a 97 with a NV4500 and a 01 with nv5600 and the auto is the one I have chosen to pull with.

Good luck to you what ever you decide, and if you go with the auto get in touch with TRE.

 

So far I am impressed with the durability of the G56 and the SB clutch behind it. Between pulling 40,000+ pounds down interstate, and entering 5 truck pulls with 5 wins all this with running 37 in truck tires, the G56 is a good tranny.
I have pulled against a few 6.7's with the new 6 speed auto, That is a tranny with potental

 

A NV 4500 with a 1-3/8" Input shaft is stronger than a NV5600 with a billet output shaft.

 

not bad but at what HP were you pulling the sled at? thats what would kill it.

 

TST on 3/3 and Smarty on 9. I haven't made it to a dyno yet

 

If you can afford to build a auto, they are tough! Some manuals are cheaper to get together to certain points. Both have advantages and disadvantages. I love my auto. Wes