Who has them and do you like? Pros and cons vs. 8.1 ally? Anyone ever swapped trannys? Thanks guys

The Alli has alot more TM obviously and more parasitic loss than the ZF6.

I owned a 02 reg cab 4x4 with that combo and i hated it. The truck ran good empty but when i pulled my buddys mud truck or my trailer with 2 antique John Deeres it would always run out of power on hills when pulling in high gear and when you shifted into 5th it seemed like the motor was too high in rpm and out of its power band. This truck had a 4.10 rearend ratio also. My other 8.1 truck with the allison was better but it still seemed like it was'nt geared right and it had 3.73s like all of the dmax trucks. All in all i say get the allison with the 8.1.

I have a 2002 8.1L/ZF S-6, it is a pulling beast. I out pulled my buddy's 2001 Cummins with almost the same load. I cannot think of anything negagtive to say about it.

My experiences with my regular cab are definately not the same as Blk04HD's. At 3300RPM in 5th gear at 70 mph, I am yet to find a hill on any Missouri interstate that I lose speed on while pulling 11,000#.

I will be keeping this truck forever. This truck is not for sale for any amount of money.

i got a reg cab 25hd 4x4 with the 8.1 and zf6 and in the summer i pull my 40' enclosed i almost never get out of 6 gear. like mentioned above aint no hill in missouri gonna hold ya back did i mention i gross 13 ton and pass anything i want

There's hills in Missery?

I have a 2002 8.1L/ZF S-6, it is a pulling beast. I out pulled my buddy's 2001 Cummins with almost the same load. I cannot think of anything negagtive to say about it.

My experiences with my regular cab are definately not the same as Blk04HD's. At 3300RPM in 5th gear at 70 mph, I am yet to find a hill on any Missouri interstate that I lose speed on while pulling 11,000#.

I will be keeping this truck forever. This truck is not for sale for any amount of money.

Yeah and you get about 6 mpg too :o: With my dmax i can get better mileage loaded than i could empty with either one of the 8100 trucks.;)

Where are you guys finding the 8.1/zf-6 trucks???? I want one!!!

Where are you guys finding the 8.1/zf-6 trucks???? I want one!!!

No you don't...and shall i mention that pos plastic squawking thing they call a clutch pedal.

I wont argue fuel mileage. But I know what I get, and 8~9mpg is a little closer to what I get in the hills. I can get 10mpg towing in flat ground. Pretty good mileage #s if you ask me. The ONLY time I ever seen close to 6mpg was one occasion when I was towing 85mph into a headwind. However, empty, on the highway, I get almost 15mpg.

I have talked to some '08 6.4L PSD owners that can do no better than me on MPGs. When you consider my 8.1L engine/ZF S-6 transmission/11.5" AAM rear axle package was only an $840.00 upgrade from the base 6.0L/5sp/10.5" AAM axle, in my opinion, it was a steal.

As I say, I can't find anything negative to say about the 8.1L/ZF S-6.

But back to the OP's question, I drove a 2001 8.1L/Allison before I ordered my truck. By the time my truck came in, and I got to drive it, there was too much of a gap in time to really compare the two, but the 8.1L/Allison should be a very capable workhorse.

Where are you guys finding the 8.1/zf-6 trucks???? I want one!!!


I had to order mine. Back in Sept,2001 when I bought mine, it was the first one that any of the dealers in my area had even seen. And yes, I took it around showing it off.

Yeah and you get about 6 mpg too :o: With my dmax i can get better mileage loaded than i could empty with either one of the 8100 trucks.;)

you may get better mileage but when diesel was 4.50 a gallon and gas was 3 it didnt make much difference did it i get about 9 mpg pullin 13 tons just about all the time worst was 7.7 on a two lane road behind a granny in the ozarks but i got a dmax in a 06 3500 4 door dually with about 8000 miles now ill agree it aint broke in but my best was 16.5 with the allison and about 12.3 with the trailer

I got double the mileage of both the 8100s i had, ive got a lb7. I get 20+ most of the time empty in the summer with a 80 horse tow tune. i get about 13.5 with a 20k load.

I had an 02 zf-6 and wish i had it back. It ran like a raped ape and honestly the duramaxes that I run now dont pull any better if even as good and loaded heavy they dont get any better mileage. A lot of people get pissed at me when I tell them that but I cant change the truth. Only problem was that the stock clutch is weak but South Bend has the cure for that.

http://www.autotrader.com/fyc/vdp.jsp?ct=u&car_id=257357588&dealer_id=100030512&car_year=2003&rdm=1237940045306&model=CHEVC25&num_records=25&systime=&make3=&make2=GMC&highlightFirstMakeModel=&start_year=2002&keywordsfyc=&keywordsfyc=&keywordsrep=&keywordsrep=&engine=&certified=&body_code=0&fuel=Gasoline&awsp=false&search_type=used&distance=0&marketZipError=false&model2=GMCC25PU&search_lang=en&sownerid=91313&showZipError=n&make=CHEV&keywords_display=&color=&page_location=findacar%3A%3Aispsearchform&min_price=&drive=4+wheel+drive&default_sort=priceDESC&seller_type=b&max_mileage=&style_flag=1&sort_type=priceDESC&address=81230&advanced=y&end_year=2006&doors=&transmission=Manual&max_price=&cardist=1115&standard=false

Here is really nice 8.1/zf-6 truck!

love my 496/Allison. heard the allison is better built than the zf. but dont know if thats true. all though the Allison is built extremely well.

love my 496/Allison. heard the allison is better built than the zf. but dont know if thats true. all though the Allison is built extremely well.

Where did you get that 496 allison badge?

they are on ebay all the time

Where did you get that 496 allison badge?Probably from the same outfit that I got mine. Flips Graphics on Fleabay.

See? Fleabay is good for something worthy from time to time. :D

Anyone know the production numbers of the ZF-6's? Just curious. I've only ever seen one that was behind an 8.1. Never seen a D-Max with one. Had to be less than 1% of the pickups made I'm sure. Back in 2005 when I bought my 2500HD I wanted to get an 8.1 originally, more specifically one with the ZF-6. First off the dealer said he didn't have any 8.1's only the D-Max's and 6.0's, and second the odds of getting a manual were slim to none with the options I wanted. Oh-well, I like my 6.0. It does what I need it to do. Now the manuals are a thing of the past (as far as GM pickups).

The figure I was quoted during a tour of the DMAX plant was 3% of engine production was outfitted for the manual. I'm sure the 8.1L was similar or less.

Well I guess I can see why they don't offer the manual anymore. The auto's sure are nice, but there's times a manual just has it's place. How do think it will be before the manual in general is gone from Ford and Dodge as well? I see a ton of Dodge's with manuals yet, so who knows.

I read Ford will drop it in 10' but who knows if that's true. There are still way more Dodges with manuals than autos so I don't see then dropping it anytime soon.

You ever get up to NE you can look at mine.

Well I guess I can see why they don't offer the manual anymore. The auto's sure are nice, but there's times a manual just has it's place. How do think it will be before the manual in general is gone from Ford and Dodge as well? I see a ton of Dodge's with manuals yet, so who knows.

i would like an 8.1/zf6 if i could afford the gas

i have a 02 and love the stick shift....took awhile to find it

where can i get a good clutch kit for my 02 8.1 zf-6?