What are to pros and the cons of the Allison 5-speed and the ZF 6-speed transmissions? In your opinion which is better. http://www.dieselplace.com/forum/smileys/Ermm.gif

Well that depends on whether you like shifting gears or you are lazy and want the truck to do it for you. I prefer and always have when it comes to trucks to have an automatic. But in sports cars I prefer standard. I know there are pros and cons when it comes to pulling as well. I would say decide what you want to use the truck for and then ask away. I know that I use my truck for everything and I would not have it any other way as far as having an automatic. Easier on me and less worry..

I am ordering a 3500 diesel and want to build the best possible truck for towing trailers. I will be in the mountains a good bit of the time.

The stock flywheel on the ZF-6 equipped drive train fails quite frequently. I am not sure IF GM has fixed this yet. Anybody know?

Your best mileage will be the 6-sp normally.


But there are options you cannot get with the 6-sp, which is why I went with the Allison.

And what are thoes options?

In my case, I could not get Rear Seat DVD. But there are other options that only come with the center console, which eliminates the manual option.


You would have to check which options are available with the 6-sp.


Also you get a "de-tuned" version of the LLY when you order the stick. LLY w/Ally = 310HP/590TQ, LLY w/ZF = 300HP/520TQ?. This does not apply to the LB7 (2001-early 2004).

Hemm I wonder why you get a “de-tuned” LLY with the 6-speed?http://www.dieselplace.com/forum/smileys/Cry.gif

Hemm I wonder why you get a “de-tuned” LLY with the 6-speed?http://www.dieselplace.com/forum/smileys/Cry.gif


Because, IIRC, they were having problems already with the LB7 and the flywheel setup. So they elected to maintain the power output of the LB7 for the new engine when equipted with the ZF.


GM's web site makes reference to the fact that over 90% of the Dmax trucks are sold with Allisons, so it doesn't make much sense to spend R&D money on the manual transmission stuff.

Well you have a point. How hard is it to beef ut the 6-speed?

I don't think it's the ZF causing the problem, I think it's the flywheel. Seems like I've seen posts about an aftermarket unit that's supposed to be the answer.


Try a few searches for it, or maybe someone will get you a link posted here. I've not really followed it since I don't have the ZF. I ran across the GM information while trying to find out what an LLY was back in December while waiting for my truck.

Savvy up,


I also debated between the two trannies. I have always preferred the handshakers, and I didn't like the additional cost of the allison. My father talked me into the allison. The truck will hold its resale value a little better with the auto, especially since it carries the allison name. I just looked at the HD Pwr Pkg discount as a way to get the allison for $200. I still love manual trannies, but I don't regret my choice.

Thanks man I really appreciate all the advice. I was at the ATS web site and was looking at the transmission upgrade. I was wondering it that complete upgrade was a good deal and was worth me investing in my new truck?http://www.atsdiesel.com/products/products-gm-transmission.asp