mated or divorced

[Capps899]

I was looking into a M5R2 for a project truck that is 4WD. Is this mated or divorced to the transfer case?

[72hiboy4x4]

what the heck is a M5R2?
got any pics, like of the underside?

[averagef250]

The M5R2 is ford's light duty close ratio 5 speed truck transmission. If it's a 4x4 version you are looking at it is mated. The 4x4 M5R2's all use a 31 spline output which means you must use the late model BW T-case. Fords HD 5 speed, the ZF, uses a 32 spline output just like all the older stuff (you can bolt a ford 205 to a ZF with a small bit of clearance grinding to the case).

[72hiboy4x4]

Oh, light duty! thats why I've never heard of it!

[averagef250]

The M5R2 was only in 1/2 tons and rangers. It's not really that bad. Some hate them with a passion, but I've had pretty good luck with them. Thier weak link is thier fluid level. If the ATF they run on gets a pint low the tranny's main thrust bearing can get starved of oil and cook in no time. The problem is compounded because they were manufactured with rubber plugs covering the rear shift rail passages in the top plate. Those rubber plugs tend to shrink and fall out when you least want them to. All the fluid blows out the rear of the tranny and what was a perfect working tranny 5 minutes ago is now toast. The problem is easily fixed by buying 3 press in metal plugs the right size from the parts store and tapping them in. I forget what size, but it's around 5/8". When the thrust goes it usually wipes the input and the mainshaft as well. If it's driven much further once the thrust goes out, the input will not mesh correctly with the countershaft and the countershaft will gall. Once an M5R2 is beat up it's hard to bring it back to 100%.

[xxxtina63]

Isn't the M5R2 also refered to as the "light duty Mazda built 5sp"?

[averagef250]

It's got a few names. M5R2, M5OD, the mazda POS, etc. The M5R2 will handle anything a small block can dish out and anything you can safely haul with a 1/2 ton truck. If you abuse one, they will break. If you're choosing a tranny for a swap into an older truck and you may plan on banging gears, not ever checking the fluid level or letting your wife drive it then go with the ZF. A small block ZF will run you easily twice what an M5R2 will though.

I bought an '89 F-150 4x4 with 4.9/M5R2 from a friend who owns a drywall business. The truck had 240,XXX some odd very hard fully loaded miles driven by some of the not so smartest people in the world. The main thrust bearing went out in the M5R2 at about the 80K mile mark. The owner didn't want to put any money into the truck so he dumped the ATF/metal shaving mix that was in it and filled it with 80/W90 gear oil. The transmission was still working OK and very driveable at 240,XXX miles. Third gear synchro was gone, you had to match RPM's precisely to use third, but otherwise it seamed fine. Not even any unusual noises. I pulled the trans apart. Reground the precision surfaces of the input and mainshaft that were beat by the thrust eating itself and reassembled it with $25 or so in a few new parts off ebay. The tranny is in a bumpside now and works flawlessly.

[AustinTom]

I used to own a 99 F-150 swb 2wd with one in it. Never had any problems. Only had 75000 miles on it when I sold it but I abused that truck on a regular basis. The worst time luckily was only 1 mile of towing 25,000 lbs of semi trailer on a dolly. It held up, but the cluch was hurtin. In case yall are wondering "How did you get it started moving?" We pushed with a tractor.

[fordman]

i got mated several years ago i never got divorced