ZF S6-650 Ford 6 speed

[BJMarshall]

I just tore into one of these last night. Anyone else here have any experience with these?

The oil pump and cooler setup are nice, but it was the demise of this one. One of the lines got tweaked and pumped all the fluid out. Low gear seized onto the mainshaft. Seems to be a nice transmission on the inside. It's more difficult to work on than the NV4500.

 

[FordCummins]

Ive been running one in my conversion and its worked out well so far, although I blew the OD gear out of the last trans that was in the truck, however that was my own doing... . Are you going to rebuild the unit and sell it, what are your plans for the trans?

 

[BJMarshall]

It's going back in the truck. 2001 F-250. It's a shame it happened too. Truck only has 80k on it. Transmission was in excellent shape otherwise. It locked up going about 50mph. Got sideways and scared the heck out of my friend that was driving it.

Most of the other gears have bushings between the bearing and the shaft. Low gear does not so when the it seized up it ruined the mainshaft as well. Going to cost about $500 in parts to fix without labor.

It looks pretty beefy on the inside. How long have you been running yours?

 

[FordCummins]

Had 215k on it when I blew the OD out of it. 200k of that was with the PSD. 15k was with the Cummins. I had clutch slip issues after the conversion was done, and wanted to see if they still existed. Truck was running in OD, at 45 mph, up a SERIOUS grade when I laid into it HARD. I never pulled it apart, but was told the snap ring that holds the OD gear on probably broke. All the other gears worked fine and I drove the truck for 2 more weeks with no OD.



Ive got 10k on new ZF that I put in and its been working well so far. Its hard to find guys running alot of power through the ZF, but its been holding up to my combo well so far.