2wd BII transmission

Mr. Tarkanian · Jan 25, 2014

Hi all, I am wanting to tackle the 5 speed swap soon, and I found a 2nd gen bronco II in the bone yard the other day. It's a 2 wheel drive, with 5 speed. I know that it will have the dummy t case, does that mean that the trans tailshaft will bolt directly to my t case? I assume it is the FM146 but I didn't get a good look at it. Is there a remote possibility it is the M5od? I'd rather wait out for the mazda trans but am having trouble locating one.

Thanks in advance.

4x4junkie · Jan 26, 2014

If it has the dummy case, it's a 4WD version and will bolt up to a real case as well.

M5ODs are very rare at best in BIIs. I've only seen 4WD M5ODs behind 2.9L engines in some 1990 Supercab Rangers, to either side of that year I've only seen FM146s. This isn't to say they never made it into any BIIs, but I've yet to stumble onto one myself.

4.0L M5ODs will fit yours also but have slightly taller 1st, 2nd, & 3rd gear ratios.

Mr. Tarkanian · Jan 27, 2014

Gotcha, thanks a bunch for the help.

Would I be an idiot for swapping in an FM146, rather than waiting for the M5od?

I'm planning to run 4.88's and 31 inch tires. Mostly for street use with VERY mild trails.

As a side note, I pulled my auto brake pedal and cluster shift indicator out this weekend. Swap is officially started :icon_thumby:

country0001 · Jan 27, 2014

M5OD's were found in B2's built after 11/89.
I have one in my B2.

4x4junkie · Jan 27, 2014

Ok, cool. That's the same starting date for the SC Ranger I mentioned.

A FM146 would probably hold up fine if you overfill it by about a half-quart (put almost 3 whole quarts in). It seems they suffer from fluid starvation in addition to the inferior ball-bearing design they use, which just exacerbates the problem. Just keep in mind if you ever decide to do a 4.0L V6 swap though (say your 2.9 someday decides it's day has come), then you'll be back in the same boat needing to swap your trans again.

Mr. Tarkanian · Jan 28, 2014

Roger that. To be honest, I'm one of the few that is actually quite happy with my 2.9, it's not a powerhouse but I like the fuel mileage and simplicity. And I figure swapping the trans will actually be the easy part, it's the pedals, hydraulic plumbing and wiring that I dread. That's not to say I wont be going to an M5od in the future anyway, but I figure this FM146 is pretty cheap and my A4LD is on the way out, so why not?

As soon as this brutal KY winter subsides I'll be hitting the scrap yards. When I have the trans in my shop I'll be starting threads about servicing it before installation.

Any other advice or input would be appreciated. Thanks all.

4x4junkie · Jan 31, 2014

Go with the FM then. If you get a 4.0L in the future, maybe you can get it along with the trans that it was paired to.
The FM trans also has a bit better shift quality to it than the M5OD (it's a little more car-like vs more truck-like).

I've been satisfied with my 2.9's performance. Like you say, it's no monster, but it seems to keep up with traffic on grades no problem if you downshift and let it wind up a bit. Many of those that complain about them often don't have deep enough axle gears for their tires, the 2.9L needs a fair bit of RPM to do it's work.

country0001 · Feb 3, 2014

Go to www.car-parts.com when you start looking for one.

Totalled · Feb 9, 2014

You may find an M5OD in a 2wd '90, but you might actually get a 2wd trans too... This was factory in Brian's 2wd '90 that he had:

2wd BII transmission

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