I got a 91 F350, 4x4, 7.3l, Diesel, non-turbo, with an E40D tranny and 4:10 axles which I am looking to upgrade to a ZF5 manual OD tranny. The reason I am looking at this change is that I am concerned about doing heavy towing with the E4OD tranny.

I got costs for a re-built ZF5 of $CDN 3,200, (could save $600 if I had a core). The clutch, bell housing, flywheel, pedal, cylinders, will probably run me another $Cdn 1,500 to $Cdn 2,000.

I can do all my own installation but from strictly a material cost point of view this is potentially $5,000 swap-out so I would really like to make sure that there are not any more hidden cost here such as the tranny not fitting up to the transfer case or major rework on the crossmember.

My questions are: 1.0 Would the tranny change from E40D to ZF5 be a direct change-out? 2.0 Does the ZF5 Tranny bolt to my existing transfer case? 3.0 Does the transfer case need to be moved and drive shaft length adjusted?.

For those of you south of the 49th Parallel the cost in $US would be about 20% less.

 

Sounds overly expensive to me. You don't need a separate bellhousing as the ZF has integral bellhousing.

Perhaps you can find a complete donor truck to get the tranny from? Could be cheaper in the end.

 

You are right on the Bell housing, don't expect the overall conversion to be cheap. I hate to start with I ZF5 I don't know the history on and have it fail a year later. It is a huge job so I would much rather do it once.

Also the old E4OD cooler could come in real handy on the E4OD especially if I am going to do heavy towing. Would need a circulation pump, no big deal.

The advantange of the donor truck would definetely be that I could get any parts such as cross members, etc... if need be.

Do you know if the ZF5 will bolt directly on my 4x4 transfer case or is there mods required?

 

I'm pretty sure the transfer case will bolt up, but I'm not positive.

If you're going to buy everything new, it will cost a fortune, as you're finding out. It would be a better bet to buy a parts truck and swap everything you need over. If you insist on going new, then you'll have to pay a premium for it. You'll also need a new crossmember.

You will also need a new PCM. The PCM expects there to be an E4OD there, and will get confused if it disappears.

 

What do I need the PCM for if the E4OD is gone? MLPS would be gone, TPS could be removed as it is no longer needed. My 93 ZF5 does not have one.

The VSS Speedometer/Odometer on the 91-F350 is still shaft driven with the pig-back sensor for the E4OD PCM so it should be un-effected as I would just unplug it. Does anyone know if the speed sensor gear is the same on the E4OD and the ZF5? If not it again should not be a huge deal as the old shaft cable is probably universal for both the automatic and ZF5 options.

The Engine Tachometer should be the same although I might have to dis-connect it from the PCM. My 93 F250 used the same two wire tach sender so all I need to figure out is how to get the signal to the gauge in the dash. My guess would be that the tach in the dash and the PCM share the same sensor and if the PCM dis-appears than the tach in the dash should keep working independently, maybe needing a bit of re-wiring at best.
I don't think the 91' had ABS brakes yet so I don't see a link there either.

Overall I can't see why I would need the PCM once the E4OD is gone. Let me know if you see more than I see above.