87 6.9 C6 to ZF5 swap

[JackJ217]

I just picked up a ZF5 last night for my 87 f250 6.9. It currently has a C6 which shifts very harsh and it is not great on the highway, which is where my truck is most of the time. I've browsed the forums and gotten most of the answers I was looking for, but I have a few unanswered questions.

The guy had it in his 97 powerstroke. He gave me the driveshafts, a south bend clutch, flywheel, and pressure plate (which I can't use) as well as the master cylinder and clutch line.

I was in the process of trying to get my cruise control working - would cruise even work with the ZF5 trans? If not I'll just forget about having cruise.

Will my starter work with the ZF5? I haven't seen anything about needing to change it, so I would assume it will.

The trans is an s5-42 out of a 94 idi. I had thought that all s5-42s had a cable driven speedometer, but I think I may have been wrong. Unless I'm just not seeing it?

I know I'll need pedals and a master cylinder for an 87-91, but what about the clutch line? Do I need one for an 87 or a 94? Or is there a chance the one off the powerstroke will work?

I didn't think to grab the yoke off the rear axle while I was there getting the trans. I think the truck it came out of was a short bed, mine is a long bed. So either way I will probably need to have the driveshafts modified, unless I just reuse my originals? Not sure if they'll hold up to as much torque as the ZF driveshafts though, as from what I'm seeing online they were built to be more heavy duty.

 

[IDIBRONCO]

Your starter should work with either transmission as far as I know. The later s5-42s didn't use a speedo cable. The speedometers got their signals from the vehicle speed sensor on the rear end. Unless you're planning to make big power or always have the pedals to the floor (clutch, brake, and throttle), I'd think that your current driveshafts should hold up just fine.

 

[JackJ217]

I think what I’ll do is swap transfer cases so that I can keep my speedometer and cruise control (if I can get it working lol) from what I’m seeing my 1345 will bolt right up to the zf5 in place of the 1356?

 

[IDIBRONCO]

Yes it will. That would be the easiest way to go about it. You also won't have to change the front of the driveshaft. The 13-45 has a yoke that is attached directly to the back of it. The 13-56 uses a slip yoke from the driveshaft.

 

[JackJ217]

Yes it will. That would be the easiest way to go about it. You also won't have to change the front of the driveshaft. The 13-45 has a yoke that is attached directly to the back of it. The 13-56 uses a slip yoke from the driveshaft.

Interesting. There’s no slip yokes on mine. Maybe someone installed a slip yoke eliminator at some point?

 

[IDIBRONCO]

I may be wrong on that, but all the ones that I've seen had a slip yoke.

 

[onetonjohn]

I thought F-250 has slip yoke, and F350 was fixed. On the front driveline F350 has the double joint knuckle (forgot what they call it) and F250 is single. I could be wrong too. That's just what I have in my head - no idea where it came from.

 

[JackJ217]

The guy I bought it from had it in his 97 350, but the trans was built in 94 so it was swapped into there at some point, but that would make sense that it was originally from a 350. Although the driveshafts I got with it just have standard U-joints, not cardan joints

 

[onetonjohn]

Cardan joints. That's what I was trying to think of. They are mo' better.

 

[Nero]

My 350 has a slip.... The t case came of a donor 350 sclb

 

[onetonjohn]

My 350 has a slip.... The t case came of a donor 350 sclb

So much for that theory...

 

[KansasIDI]

BW4407 transfer cases from the 96 and 97 diesel trucks were also slip joint in the rear.

And had a PTO cover…

 

[JackJ217]

Well now I’m really confused… the t case that came with the zf5 is a 1345, not a 1356. But I’m still not seeing a spot for a speedo cable

 

[Nero]

Well now I’m really confused… the t case that came with the zf5 is a 1345, not a 1356. But I’m still not seeing a spot for a speedo cable

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[JackJ217]

Yep, that's it. Might still end up using my original transfer case since I know it works. Would that transfer case have been swapped onto that trans at some point then? The trans was built in January of 94, so it was the last year of the S5-42 which should have had a BW1356 case on it as far as I know.