Ok, that makes sense. I knew the LLY was still available but didn't know with what package.

Thanks for the info.

 

6 speed is only available with the LB7 engine...the very first Duramax engine! As far as I know at least!!

They say the ZF6 won't handle the higher power

Chris

 

Yup... 300 Hp 520 TQ if you get the 6 spd standard... I guess you need a fluid coupling in there to take the massive torque.

 

I can't say I blame them...that Dual Mass Flywheel would make me scared, too

Chris

 

Yup.. There is a mechanic fleet around here (12-13,000 Lbs service bodies) with a couple DM's and they got 6 spds thinkin they would avoid tranny problems.. WRONG... They were in the shop at least once every couple months with clutch and flywheel related problems.

They have since went to the Allison, kept the GM's.. Oh well, some never learn...LOL.

 

The LB7 is not in production anymore. As of 04.5 they went with the LLY. (It has lower power/torque then the LBZ)

 

Exactly. But, in defense of previous posters, the power level has never increased from the original LB7 for those of us who prefer to shift our own gears. Also, the '06 variant of the LLY gets all of the same internal goodies (stronger block, bigger rods, etc.) as the high output LBZ. The ZF6 can handle more than any stack power boxes can throw at it. Unfortunately the flywheel disentegrates quicker if you add much power over stock.

 

Yal are right should have been LB7 not Z.

 

I was close...it's not my fault GM has never changed a power rating from day 1, but changed engine designations 3 times

Chris

 

Ok, my bad as well.. but I must have missed the fine print.

Why is a flywheel the weakest link?? Talk about engineering breakdown on something easily replacable, but no, keep it for 5 production years... Again, having to redesign the bottom end for a 60 hp bump seems pretty fishy to me. The CTD power ratings have just about doubled since its debut and the bottom end is essentially the same. Hmmmmmm.

 

It is a Dual Mass unit...I don't know much about them, other than they are trouble! I think they are two piece, and are supposed to hep take some shock out of using a clutch?!

Chris

 

The concept is that the heavier mass of the flywheel can better absorb the idle spike characteristic of a diesel engine compared to a simple clutch damper on a gasser. You can use a spring dampened clutch with the tradeoff being more rattle in neutral. Dodge used one successfully for years until the HPCR engines came out. Now the engine is quiet enough for people in the cabin to hear the gear rattle using that set-up. The newer Dodges with the G56 use almost the same identical LuK flywheel as the Duramax. Supposedly the difference is that GM opted to use a plastic bushing between the flywheel halves while Dodge went with an improved metal bushing. GM was offered the option but didn't want to spend an extra 10 cents per flywheel.

 

Ya know I forgot about that change with the G56.. Why would GM opt out of that offer???

Has there been any reported problems with the CTD flywheels?? I see SBC already has an aftermarket wheel..

 

I haven't heard of as many problems with the CTD flywheel, but I admit that I don't follow the CTD forums as closely. SBC just finally released a single disk kit for the Duramax. I wonder if it's similar to the CTD kit you are referring to.

As for why GM didn't jump on the upgraded flywheel, why does GM do all of the other stupid things they do?

 

What?
The LLY has two power levels, depending on the aplication. the Van gets something like 250/450, the 6 speed manual gets 305/590 (I think!) and the Allison gets 360/650. The day one you are talking about was 300/520. So you were wrong, and GM HAS changed the power ratings from day one.