alright guys im still workin on my bronco custom, slowly but surely. i gotta swap out my tranny for a new one and im in a debate, it has an M5OD in it currently but it crapped out at 82,000 miles and ive heard that the ZF is a better tranny so what do you think? should i get a ZF or get a new M50D? would the ZF mount up to my inline 6 no problem?

thanks, matt

 

There are quite a few 300s that came from the factory with ZFs behind them, so it shouldn't be a problem. The clutch/slave cylinder/etc. setup may be a little different. I can't remember between those two.

The M5OD and the ZF5 are set up a little different as far as gear ratios go. The M5OD is a 1st, 2nd, 3rd, 4th, OD whereas the ZF is a Low, 1st, 2nd, 3rd, OD.

The other biggest issue you'll deal with with the ZF is cost. They can be very expensive to get a hold of in a small block, 4x4 configuration. (Which, be SURE it's a small block four wheel drive version, and not a big block).

 

yeah im not sure about it, ive heard alot of good things about the zf but i did hear there a lower gear ratio. im lookin online for a certified used tranny with a warranty and it seems like i found one but its cheaper than the m5od they had.

 

The ZF is considered an upgrade for our trucks, i say go for it. Do a little research, there have been several of these swaps made in the site, check the F-150 section too, and ask your questions. The ZF is a little longer than the Mazda, and you'll need a couple of other parts to do a proper swap.

 

I have had both in my truck and the ZF is *shorter* than the Mazda.

 

Hmmm, then i got that wrong, probably got confused thinking since it's a HD tranny, it must be bigger, thanks for the correction. Or maybe there is a shorter version of the ZF, i'll have to check that...

 

Ok, guys I tried to stay away but this thread is something I'm working on myself right now. (Just can't let info stay in my head if someone really needs it).

The ZF and the M5 are (at MOST) 1/2" different in length, M5 is actually longer but a 1/2" isn't significant enough to require any changes to driveline. (I have the two units OUT of the trucks and side-by-side in the garage right now). The clutch components for both transmissions are identical... meaning you can use M5 clutch parts in front of the ZF and vice-versa. The mounting points are identical for the rear mount although the mount itself may need to be thicker for the ZF. Linkage bolt locations are the same as well. Ratios are as follows:

The S5-42 ZF(which is the unit in the heavy-duty Fords from the same era as the Bronco) came with either a close ratio gear set or a wide ratio set. The tag on the casing will indicate ratios.

Close Ratio
1st Gear:
4.14
2nd Gear:
2.37
3rd Gear:
1.42
4th Gear:
1.00
5th Gear:
0.77
Rev Gear:
3.79


Wide Ratio
1st Gear:
5.72
2nd Gear:
2.94
3rd Gear:
1.61
4th Gear:
1.00
5th Gear:
0.76
Rev Gear:
5.24

The M5OD or M5R2 (which is the unit in the F-series from that era) has one gear set as follows:

First 3.75
Second 2.32
Third 1.43
Fourth 1.00
Fifth 0.75

While the M5 has the capacity to have the tailhousing removed and a 2WD tailhousing installed, the ZF cannot.

 

You came back i'm glad you did, now let's not hijack this thread guys (for the others posting after me).

 

haha ide love all the help i can get, and thanks alot greystreak, youve been helping me with this bronco since my first post haha