I spent some time online last evening looking for info on doing an auto to zf swap and found that most of the thread/posts were lacking any real in depth info in doing such a swap. Most only seemed to be a few posts long and covering just one or a few points in the swap process (ie. engine/trans bell housing bolt patterns). I even ran across a couple of points that seemed to me to contradict each other (ie. MLPS sensor and a resistor (unsure what was going on with this)).

It can be very difficult to gather all the info on such a swap when the threads cover four different generations with different trans engine combos, each with their own set of challenges.

With the number of threads started involving questions about such a swap there seems to be high interest in this swap. So I'm wondering if there is any way to get a sticky tech thread put together, in detail, about doing this. I've heard about it being done and how happy they are with the swap. So how about sharing this info with everyone thinking about it, again in detail?

 

The MLPS is unique to the E4OD transmission. The question has to do with the removal of an E4OD and "fooling" the computer into thinking that the E4OD is in a moving gear. If your swap happens to entail this process, you will need to know it or swap computers. The computer must be from a Bronco or F-series with the same engine and a transmission OTHER than the E4OD. The E4OD and in very late models the 700r4 were the ONLY transmissions that were electronically controlled by the onboard computer. The manual units and the C6 (vacuum regulated shift) and AOD (throttle valve cable shift) were not.

ZF S5-42 (herein referred to as the ZF) is identical in overall length (bell-housing to t-case flange) to the M5OD that was available OEM in the Bronco. This means that the STOCK driveshaft lengths from a Bronco with an M5OD can be used when swapping to a ZF without the need for "custom" DS lengths. The clutch components, bearings, hydraulics, etc are also the same. The rear support location is identical to the M5OD as well as the bolt spacing for the rear mount (same transmission mount for both). The ZF and M5 rise to the same height at this point above the bottom of the flange for the mount.

The E4OD, surprisingly, is only about 3.5" longer overall than the ZF (best measurement I could take with the E4OD still in the truck). This also pushes the rear transmission mount back from the bell-housing flange for trucks equipped with this trans. This means that when swapping to a ZF or M5 from an E4OD you will need to lengthen the rear drive shaft and shorten the front driveshaft. The nice thing is these alternate lengths are the STOCK lengths for the drive shafts in a Bronco equipped with an M5OD. So the need for "custom" DS lengths is minimized. The wiring harness to the MLPS will have to be pulled back and a resistor used to jump between the common and "DRIVE" terminals in the connector for the MLPS. (See E4OD note below) The transmission cross member will need to be moved forward to accommodate the shorter ZF. However, the frame rails (on my 92 and 93 models) already have the necessary holes for relocating the cross-member AND the gussets. The transmission mount is the same for the E4OD as the ZF and M5 with hardware spacing and dimensions being identical. There has been discussion that the cross-member from the ZF-equipped donor truck will be needed. Based on the hands-on research I've done, I don't seen that being a necessity unless the aft transmission mount for some of the transmissions that I don't have measurements on is significantly different.

GREAT BIG NOTE: None of this information takes into account any change in forward or aft movement due to an engine swap. For the most, part, stock engines all line up on the same axis fore-to-aft leaving their flywheel or flex-plate in the same location regardless of which engine is in the truck. This assumes the use of OEM (stock) motor mounts and engines. Engines not available OEM or OEM engines not mounted in their stock configuration could affect driveline lengths and shift the position of any transmission swapped.

E4OD NOTE: The MLPS uses different resistance values to "tell" the computer what gear has been selected. The resistance values for each position are as follows.

In 1992 and later models, the GREY/RED wire sends the MLPS signal BACK to pin 46 of the PCM. The LT.BLUE/YELLOW wire receives voltage FROM the PCM and alters it depending upon which gear the MLPS is in.

The resistance values between these two wires are as follows.

PARK - 4189 ohms
REVERSE - 1448 ohms
NEUTRAL - 733 ohms
DRIVE - 401 ohms
2ND - 211 ohms
1ST - 85 ohms

These values may be the same for 89-91 models equipped with the E4OD but the diagrams depict the resistors as being series wired rather than parallel. Meaning that the resistance value would compound with each successive gear selection. i.e. in DRIVE the resistance would be 717 ohms or 85+211+401. PLEASE NOTE that this is a GROSS ASSUMPTION based solely upon my personal interpretation of the wiring information that I have available to me. I cannot confirm the validity of this assumption.

Some numbers that might come in handy:

M5OD and S5-42 (ZF)
Bell-housing flange to t-case flange (overall length) 29.0"
Bell-housing flange to aft transmission mount bolt 25.0" O/C
Aft transmission mount bolt spacing across mounting flange 5.5" O/C
Height of tail-housing from aft mounting flange surface 8.5"

E4OD
Bell-housing flange to t-case flange (overall length) 32.5" (approx.)
Bell-housing flange to aft transmission mount bolt 29.5" O/C
Aft transmission mount bolt spacing across mounting flange 5.5" O/C
Height of tail-housing from aft mounting flange surface 8.5"

I don't have these measurements for the T18, NP435, C6, or AOD. If someone would like to add them, by all means do.

A comparison chart of sorts for gearing differences between various manual and automatic transmissions.

Transmission - 1st, 2nd, 3rd, 4th, 5th, Rev. (reverse gearing listed for the ZF only).

T18 - 6.32, 3.09, 1.69, 1

C6 - 2.46, 1.46, 1

AOD - 2.4, 1.47, 1, 0.67

E4OD - 2.71, 1.54, 1, 0.71

NP435 - 6.69, 3.34, 1.79, 1

M5R2 (M5OD) - 3.75, 2.32, 1.43, 1, 0.75

ZF S5‐42 (M5HD-1)
Close Ratio - 4.14, 2.37, 1.42, 1, 0.77, r3.79

Wide Ratio - 5.72, 2.94, 1.61, 1, 0.76, r5.24

The S5-42 case number (for identification purposes) is "1307"

Does that help buck?

 

There is a good deal of info to chew on, thanks. One question that popped into mind when reading this. Last year when I was still looking for a Bronco and on here asking questions about them and changes to make, you mentioned something about putting the MLPS sensor in netural and that would make the Bronco run properly. Is this still true, or was that info for some other combo?

As far as drive shafts go, I am going to assume that a F150 M5OD front shaft will work, and the rear shaft MUST be out of a Bronco with the M5OD. Is this line of thought correct? 92-96

I didn't give much thought to the swap after I got my Bronco due to the extremely low mileage and great shape of her. But I was in the junk yard yesterday ( co-worker told me he seen a couple of Ford trucks and a F 350 I might be able to uses parts off of for my 89 F350) and found a 91 F250 4X4 with the ZF, got to wonder about the swap again, and if I should spend the money and time to pull it or not.

 

You are correct about the MLPS being left in "neutral" as a possible solution to "fooling" the computer. And yes, the front driveshaft from an F-150 with an M5 should do the trick. You will just need one for the rear from (or made for) a Bronco so equipped.

Personally, I'd do it just because it takes the transmission out of the equation when it comes to weak points in the drive line. But then, I would eventually like a Bronco with a 300/ZF/NP205 (twinstick 'cause I can't afford an Atlas right now)and heavier axles.

 

I'd like to do it, due to my utter hatred of autos. I get so sick of up shift down sift converter lock unlock shift lock shift lock and on and on and on. I could never understand under certain situations you step on the gas rpm's come up then the trans does something kills the rpms and the truck lugs, falls on it's face, before a complete down shift out of O.D. My 95 F150 did the same thing at the same places. I always blamed it on the under power of the 302 along with the auto, but the 351 in the Bronco does the same thing. So in my eyes it just proves to me how much I hate auto transmissions.

He's asking $200 for the trans. Guess I could get it while the getting is good and put it back until I could gather the rest of the parts needed for a proper and professional looking swap.

 

Slushboxes in trucks have little purpose for me either. Jump on a 4WD S5-42 if you can. They aren't as easy to come by as one might think. I added some information about the MLPS issue up above too.

 

I was going to ask if you added info to your first post, thought I was loosing my mind at first; but then I saw your reply that you did.

Shame you don't live close to me. The 91 F250 that has the ZF is a 300. He'd take $200 for the complete engine.

As far as the ZF being hard to find, I know. Finding one that will work in my Bronco is the only reason I started thinking about this again, thus leading me here to seek more info.

 

I have an EFI 300 out of a 92 F-150... I just need something that is at more of a premium than 4WD ZF's.... time!

 

Time I can find, now money that's the hard part!!

There are a few Ford trucks up there now that have the 351 in them. I'd love to grab one for the Mustang but alas I don't have enough money to start yet another project.

 

http://www.jaxed.com/cgi-bin/sd.cgi?...ate=&submit=go

I see ZFs on this site (craigslit aggregator) all the time...

 

http://www.jaxed.com/cgi-bin/sd.cgi?...ate=&submit=go

I see ZFs on this site (craigslit aggregator) all the time...