'94 2wd B3000 M5OD-R1 Swap/Replacement

[Alexkoch]

Hi all,

Thank god this forum exits. I have a 1994 Mazda B3000 2WD with a possibly busted M5OD-R1 trans.

I'm looking to replace the transmission and before I take the plunge, I'd like confirmation on which options I can pursue and that I have the correct scope of work.

Option A) Replace with identical M5OD-R1 from any 91-94 2wd 3.0L Ranger/B3000. This would be a simple bolt-in job.

Option B) Replace with an M5OD-R1 from a 95-97 2wd 3.0L Ranger/B3000. I would have to do something with the speedo correct? Could I use the system on my current transmission to replace the VSS sensor set up used on this transmission?

Option c) Replace with an M4OD-R1 from a 98-11 2wd 3.0L Ranger. I would have to swap the tailshaft from my current trans onto the newer box to get my speedo to function.

Thanks all!

 

[Alexkoch]

Ah, and if anyone could point out what may be wrong with my current box, that might save me some $$$.

Currently, I cannot shift into any gear while the engine is idling. As soon as the truck is off, I am able to select any gear as normal. If I start in gear, I'm able to move but the gearbox sounds like some metal to metal grinding is going on. Clutch feels fine. No leaks.

The truck has only 109k miles. Wondering what I may have done wrong/what to look out for next 100k.

 

[Spott]

Ah, and if anyone could point out what may be wrong with my current box, that might save me some $$$.

Currently, I cannot shift into any gear while the engine is idling. As soon as the truck is off, I am able to select any gear as normal. If I start in gear, I'm able to move but the gearbox sounds like some metal to metal grinding is going on. Clutch feels fine. No leaks.

The truck has only 109k miles. Wondering what I may have done wrong/what to look out for next 100k.

The evidence seems to point to the fact that the clutch isn't disengaging. If you start it in gear, can you shift when rolling, if you regulate the engine speed to match the transmission speed?

 

[Alexkoch]

Thanks for the reply.

I haven’t tried to drive it far/fast enough to shift into 2nd yet. Once I heard the grinding I switched it off and parked it.

If it were a clutch disengagement issue, what could be the culprit?

 

[MrE_Powers]

i took a 98 m50d swapped the shifter and tailhousing from my 93 transmission. it worked fine

 

[Spott]

Thanks for the reply.

I haven’t tried to drive it far/fast enough to shift into 2nd yet. Once I heard the grinding I switched it off and parked it.

If it were a clutch disengagement issue, what could be the culprit?

Culprit might be low clutch fluid, air in the lines, bad master cylinder, bad slave cylinder, or bad linkage/pushrod.

If you're getting grinding noises (after releasing the starter) then you've probably got more issues or other issues than just clutch problems.

 

[Alexkoch]

Thanks all!

I pulled the transmission and discovered a roasted pilot bearing. Looks like it did a number on the input shaft too. I think I'll have to replace that...

For those interested, to remove the top two bell housing bolts (holy f*** that was a bear) I bought two 10" 1/2 drive extensions and a set of flex-head impact sockets to get to the bolts. I also had to remove the rear trans support bracket and using a jack, lowered the trans/engine about 6". Then used an impact wrench to get the two bolts out.

What made it more challenging was I just graduated and moved out of my parents house from SoCal to downtown San Jose, where I can only pay to street park. And I own no tools.

So instead of paying a shop to do the work, I spent the $750 worth of labor to get myself tools and used AAA to tow my truck to an empty parking lot to do the work. Then it started to rain.

What an adventure.

 

[delaware74b]

FWIW, I pull those top 2 bolts from the top, from the engine compartment. I use a short 15mm socket on a 3/8" flex ratchet. They're the first bolts I pull before raising the truck. I learned that trick the first time I pulled the transmission for a slave cylinder.

 

[Shran]

4 cylinder trucks are super easy to work on! Especially the bellhousing bolts, it gets a LOT tighter with a V6. I do them all from below - Harbor Freight has really long 3/8 extensions that work great here, with a 13mm swivel socket.

Good work on the parking lot job - haven't had to do that in quite a while, it sure builds character and makes for good stories.