Details of a ZF manual transmission swap
 

I have just completed a ZF-S5-42 (wide ratio) transmission swap in my 1989 Ford F150 Lariat (SWB, 2WD, I-6) replacing the Mazda M5OD-R2 unit. At the same time, I bought a new clutch slave cylinder and an 11” clutch assembly kit (from Advance Auto, replacing the existing 10” clutch) and bolting this to the existing original flywheel (which accepts both size clutches). The clutch kit includes the pressure plate, the clutch disk, the pilot bearing, pilot bearing-clutch disk alignment tool, and the clutch slave hydraulic line removal tool. The transmission input shaft spline is the same for both transmissions.

While the transmission was out, I replaced the rear center freeze plug behind the flywheel. (No need to replace the lower left rear freeze plug as that is to the camshaft galley, which won’t rust thru). If you use a rubber expandable freeze plug, you must cut out the dust cover sheet that fits between the engine and transmission to clear the big washer of the plug, since they fit in the same plane against the block. Also, grind down the stem of the expandable freeze plug to the nut to clear the ring gear on the flywheel.

I drove out the old pilot bearing by filling the bearing cavity full of grease and installing an appropriate size dowel into the bearing and hitting it with a hammer. The new pilot bearing was a non-interferenced fit, so I put blue threadlocker on the circumference of the pilot bearing cage and placed it into the end of the crankshaft.

The transmissions are heavy, so have a buddy to help you jack it up into place. I cut the heads off of two 4” long 7/16 bolts to use as extended guide pins and screwed them into the block just above the existing short guide pins. This was helpful because the tranny has an integral bell housing, which makes perfect parallel alignment to the engine during assembly cumbersome. Also the tranny is tall with the integral bell housing, so jack the front end up high. I used a floor jack handle pipe wedged between the front suspension under the pan to support the engine. That way I could slide the tranny in and out of the front of the truck as there was no jack in the way. I still had to slide the trannies in and out on the floor because when on the jack, it was too tall to slide under the truck. The ZF requires 6.8 pints of type H ATF oil, not hypoid gear oil as you might imagine.

The ZF has a U-joint companion flange at the rear whereas the M5OD-R2 had a conventional slip joint. I took the original driveshaft with all the critical dimensions to a drive line shop for modification. (The flange to flange length for my vehicle is 59.25”).
The driveshaft was cut and a spline was installed at the front end. On this spline went a slip joint yoke to match the ZF flange. Note that you need a slip joint in the driveshaft for suspension travel. Both U-joints turned out to be the same size. The U-joint caps for these Ford U-joints are 1.125” in diameter. The stop tabs in the companion flanges measured to 3.63”. (This is the same dimension as the width of the U-joint with caps installed).

The cross member was stamped as M5OD but the ZF bolted to it with no modification or problem. I used the original rear transmission mount.

The trick to remove the clutch slave hydraulic line is to push hard on the white ring with the tool (included in the kit) and then while pushing, slightly pry the tool outward from the case. The line disconnected immediately. I reinstalled it to the new slave by just pushing the connector firmly back into its receptacle until it clicks in place. Bleeding is simple – just open the bleed port (install a hose on it first) and let the fluid drain until clear. Be sure to keep the clutch master cylinder full while you do this.

Good luck! You’re going to love the ZF with the 11” clutch.

what is the main difference you noticed switching to the heavier duty trans? I really want a ZF (but i've gotta switch from the e4od...)

ZF tranny swap
 

My M5OD was going bad and I had a friend who had an extra ZF laying around.

What I like is the granny first gear for real low speed maneuvering on my property. The gear spacing in the ZF seem perfect for my 6 banger . . .

How is the shifting compared to the Mazda? I like the shift feel and action of the Mazda but hate the very high reverse gear with my 3.08s. I bet my buddy that I could beat his F 250 460 /Auto with 4.11s backwards but we couldn't figure a way to do it without dying.
regards
rikard

ZF tranny swap
 

To tell you the truth, the M5OD had shifting problems since I got it. The ZF is smooth and is fully syncroed. I like it much better than my old one because, in part, it was bad to begin with.

tranny swap
 

I have a 1989 custom lwb 300 6 . what do I need to tell a yard, or what trucks do I look for for a ZF to fit my truck?? and I just put in a new clutch, can I re-use it?? and what would I need to measure on my drive shaft and pieces would I need for this?? and what would I need from my donor truck?? drive shaft?? clutch hydraulic lines? etc?? or is there a better tranny?? I hate my mazda one

What do you hate about it?

And if you were to do the swap basically everything switches over, clutch, slave cylinder trans brace and drive shaft. I think the starter fits too.

about the mazda
 

I don't like the shifting, it doesn't wanna go in second, it is super slopy in changing gears, (has at least 4 in of play in gear!:censored:), and it strains and kicks when towing, other than that I have no problems lol, plus I tow alot, got 3/4 ton springs with helpers, trailer brakes, and upgraded cooling. I just need a beefeier transmission, is there another transmission that would be better suited??, thanks, still want my over drive though, has to be a manual :D

ZF would be your best bet. You will find them in f250 and f350 trucks. You will need one thats bolted to either a 300, 302 or 351 for the same bolt pattern.

What rear gears do you have in your truck?

Basically, everything switches over (including the starter) except the drive shaft. As stated above, it needs to have your stock drive shaft yoke (in front) replaced with a slip-jointed companion flange. This is a piece of cake for any drive line shop.

The drive shaft length is determined by the distance from the companion flange flat (of the ZF) to the companion flange flat of your rear end WITH THE TRUCK DOWN OFF THE JACK SITTING ON THE FLOOR. The drive line shop uses this measurement to position the slip joint mid-way on the spline as the "neutral position" of travel.

As a thought, All State Gear offer a $14 shifter rebuilding kit for your M5OD tranny that can be installed with the tranny still in the truck. This kit will take all the play out of the shifting and it might be worth trying before you do the swap. If you decide to do this, be sure to RTV seal the three shifting rail plugs in the the tranny cover as they always leak without being sealed. Good luck and keep us posted! Jack