zf-6

[BigO-L3]

Yep........mine went out 3 times.........during warranty. It was bone stock at the time, and NEVER abused.

 

[GM Guy]

dads stock 01 lasted just over 30k with only pulling the gooseneck once in a while. and dad always drove stick pickups his whole life, so he knew how if anyone did. his int. pickup and travelall both went over 100k with original clutches.

x2, wouldn't doubt all of dad's IHs have the original. all but one has gotten good life out of the clutch, the one w/ a bad clutch has cold running issues, so you have to rev it up and slip the clutch, we bought it that way, clutch was half shot as well, ony 70 some thousand on it, once we get it tuned right, we will expect long life out of the next clutch.
They are for sure tough old trucks, ran them all the time until we got the 98 gasser, now they do all the tough local jobs, the 98 needs to stay on the highway anyway.

 

[12secondhandshaker]

My buddies that have them have all already put clutches in them. That is the weak point on them they don't hold much over stock. The Allisions seem to be able to take quite a bit more before you have to build them.

The clutch is definately the weak link. Once that is out of the way you can put alot of power to the ground without worrying about too much about the trans.

I had mine re-built around 45,000 miles due to the fact I broke the slider pin between 4th and 5th. I had the trans gone thru and replaced some gears, syncros, forks, etc. I also had the T-case gone thru and the pump rub issue fixed. I now have no worries when i go to the dragstrip and beat the hell out of the trans slammin gears. After a complete go-thru and a dual disck clutch and flywheel, I still have less into it than a mild Allison build up. Not nocking the autos but I love my ZF!

 

[JeffsJeep04]

How does the ZF take to clutchless shifting? I've never met a standard I couldn't do it in, but some are much more of a PITA to do (super picky on RPM). I could throw off some very quick shifts in my C8500 with the eaton fuller 10+2

Someday when money allows, I'd love to pick up a ECSB with a ZF6

 

[01duramax6spd]

They shift pretty good without clutching.

How does the ZF take to clutchless shifting? I've never met a standard I couldn't do it in, but some are much more of a PITA to do (super picky on RPM). I could throw off some very quick shifts in my C8500 with the eaton fuller 10+2

Someday when money allows, I'd love to pick up a ECSB with a ZF6