zf 5

Reply Subscribe

Thread Tools

Search this Thread

Feb 24, 2007 | 11:59 AM

f350custom

Thread Starter

Senior User

Joined: Mar 2006

Posts: 106

Likes: 0

zf 5

hey anyone know if a zf 6 speed would fit the 91 7.3 motor i was
thinking on trying to replace my zf 5 and put a zf 6 speed
in my 91 f350 so i would have 1 more gear any info would be great

Feb 27, 2007 | 07:17 PM

Jake S

Senior User

Joined: Mar 2006

Posts: 136

Likes: 0

From: Twin Cities, MN

All 6.9 & 7.3 idi and Powerstroke bellhousings and the same. Any trans. from any year would work. But it just splits the gears more, not a lower 1st? or taller OD. Bummer.

Feb 27, 2007 | 09:47 PM

mikeyswood

Elder User

Joined: Jul 2005

Posts: 736

Likes: 0

From: Cincinnati

There are two torque versions of the 6. ZF says not to swap torque levels, but there are guys that have successfully done S5-42 to S5-47 without problems. The bolt pattern should among all diesels but check in the diesel forum to be sure. Also, I think that the 6 is a longer unit so you would have to change the drive shaft. The gear ration is similar among the two units; you would gain some top end torque, but you would be shifting more and doing a lot of work to get it there.

Let us know if you decide to do it.

Mike

Reply Subscribe