Will 1991 f150 5 speed 300 six bolt up to 1992 f150 5 speed 300 six without any change's. Gear ratio's ect.

 

Yes they should, The trannys are the same as long as there both M5od. Look for a square pattern on it to tell. If its diamond with pto covers the ratios are different

 

Yes they will, as long as both are 2wd or both are 4wd. Ignore the part about the square/diamond pattern on the side. Both trannies are the M5OD.

 

I swapped out the M5OD in my Bronco with a ZF S5-42. The swap was bolt for bolt, didn't have to move anything. I did have to add about 6 inches in the reverse light switch leads. As far as the outside of the case - the ZF has the diamond patterns on the side, the M5OD does not. The ZF also has PTO covers on both sides, and has much deeper first and second gears, third is about the same.

 

i have a 94 f-250 3/4 ton 4x4 351W w/ a 5 speed. now im not sure which 5 speed it is, but i think its the ZF. 5th gear makes a whining noise (bearings), anyone experienced that? well i talked to a ford "professional" and he said the tranny i have was fords bad one for those years. he recomended getting one from a 90 or 91...i guess thats the M5OD? and im 200 miles away from the truck and cant look under it for a few more days to see if it has the dimaond pattern but im sure it does. I wanted to rebuild the tranny myself but the guy said i would have to buy a special tool from ford ($800) to pull the bearings. any help?

 

The F250/350s came with the ZF, the F150/Bronco came with the M5OD.

I don't know of any bad years when Ford was using the ZF. When I was researching my trans swap, I did find out that ZF transmissions pretty much sucked for a long time, then the company took a round turn and got their act together, and has been solid since Bad years? I did not find anything about any particular model years to avoid (for Fords).

 

Freakazoid!
you wouldnt happen to know when that was that the company took a turn around was would you?

 

Funny, I've always heard the ZF was a stout piece. I have one out of an 89 behind an 87 460 and have never had a problem. I have heard a lot of bad things about the Mazda. I know first hand the Mazda trans Ford put in some of the Explorers were weak (broke a third gear syncro behind a 4.0L while just driving around). I don't know if that's the same as the Mazda trans in the F150. I would check into that tool a little more. Depending on what it is, a creative gearhead could probably fab/rig it.

 

ok well i have another ? then. the tranny i have is one piece (no bell housing) w/ internal slave cylinder. does that make it the ZF or the M5OD? remember its a 4x4, but i dont think that much maters? just that a 4x4 has a longer tailshaft right?

 

The ZF had a bad rap that ended somewhere in the early 80s from my best guess. I think Chevrolet had a problem with the 4+3 model that they put in the corvettes, and there was some issue with the trannies that had CV joints coming out the sides of the back ends vice a spline coupling in the rear (them sports car types), but nothing that I could find about trannies installed in Fords.

Both the M5OD and the ZF (for the Windsor bolt pattern) are one piece with integral bellhousing and internal slave cylinder. The larger ZFs that were installed behind the diesels and 460s had an external slave cylinder.

The 4x4 model does not have a tailshaft like a 2WD - it has a coupling housing that mates to the transfer case, unless you have a divorced transfer case setup, where there is a driveshaft out of the tranny and into the transfer case.

There is another active thread similar to this one that discusses swapping these two trannies. I did it, so did HardWorkinFord (I haven't heard from him lately), and I can tell you that we both agree that the swap is money well spent, and gives your truck a lot of low end grunt, even if you have an old tired 302 (like I do).

 

There are no 'bad years' of the ZF put in Ford trucks. They are all very well built units.

If it's an F-150 or Bronco, it got the M5OD. It's basically the same tranny that the explorer got. Most F-250's got the ZF, except for the light duty F-250's with the 302. Those also got the M5OD.

There are persistent rumours that you could get a 1988 F-150 with the ZF, but I've never seen one, nor has anyone on FTE that I know of. There is lots of documentation in parts catalogs and from Ford supporting this, but it appears to be a myth.

Both the ZF and the M5OD have integral bellhousings with a concentric slave cylinder. Some of the early BB & diesel ZF's did have external slaves, but they were changed to concentric later on. Not sure of the year.

There are no factory divorced transfer cases after 1977.5 that I know of, and definitely not after 1980. But it wouldn't be too hard to set one up that way.

 

Does anyone have the tool number and manufacturer to disconnect the slave cylinder line? It'll save me a trip to the local shops in search of the answer.

 

Andym - I disagree I have a 1988 f-150 custom 300-I6 with a ZF hvy duty tranny from the factory and paperwork to prove it.

 

m1 - the hydraulic line to the slave cylinder can be disconnected without the specialty tool. It's pretty tough to do the first time it has been taken apart, but the Haynes/Chilton books tell you to use a flat screwdriver (or two) to push the white plastic piece towards the cylinder while pulling on the line. The first time I did it, I felt I needed a third hand, but eventually it came apart - I used a screwdriver with a really short blade (about two inches long) that let me put some pressure on the white thing (which doesn't need much) and wiggle the line until it came out. Good luck!

 

Awesome! You're the first person I've heard of that has one. Now I can tell people that they actually exist. Was it an option over the M5OD? In other words, could you have gotten either one?