I am new to duramax's, but have been a chevy guy all my life. The only diesel that I have ever owned was a 97 Dodge, with enough mods to go through a few clutches. After I graduate college, I will be looking seriously to buy a new truck, and since Chevy has the duramax and it is finally in my price range, I figured that I should find out a little more about them. It will be my daily driver and weekend sled puller, while occasionally pulling a trailer.

1. Which motor is the best to modify for power, but keeping street durability? I imagine that the later years have more of the bugs worked out of them, but is there any performance difference?

2. I noticed that the 6 speed trucks are rated for lower power. Are they just detuned a little more, or is the automatic motor that much better? Is a manual truck capable of the same power of an automatic? I have always been a handshaker kind of guy, and although the allison is nice, I think I would still prefer the 6 speed stick.

John

Well, the motor is the same auto vs manual trans...it's the programming that makes the power difference..
The manual trans trucks are capable of the same power...BUT the stock dual mass flywheel is really a piece of garbage...If you're going to be pulling with it, you'll need to do an upgrade there (and there are new setups coming out to help with this problem very soon :D )

Talking tuners, LB7's are putting out the most power right now. The LLY is getting there, and noone knows the capabilities of the new LBZ thats coming out.

As for trannys, the OEM clutch is a big trouble spot. GM really dropped the ball on that setup. There are a couple people out there making aftermarket single-mass setups that are taking a lot of abuse.

The Allison is a very capable auto tranny, but it too has its limitations. Anything over +100HP you should upgrade your trans.

Do some searching in the Allison and ZF topics, you'll find that its all been covered.

This may be an extreme case but if you want an example of what the lb7 duramax and ally combo are capable of visit duramaxracing.com. He's got one of the meanist duramax's out there from what I've seen.

This may be an extreme case but if you want an example of what the lb7 duramax and ally combo are capable of visit duramaxracing.com. He's got one of the meanist duramax's out there from what I've seen.

That's Michael Tomac. He's a regular here.

I have an 01' 6spd and would recomend going that way over the Allison.It's more fun to drive and it performs better for what I do.The stock DMF sucks-:t but I'll have mine fixed very soon with a SBC/SD kit from IBDMAX'IN. It's cheaper to get a reliable clutch than to build a reliable Allison.

Thanks for the replys. I have always liked shifting gears, and was disappointed to find out that the 6 speeds are lower rated than the autos. Good news to hear that its just programing. Crank It Up Diesel has a pretty good website too. Those trucks run good coming out of there.

John