The tranny has to be 3.0 specific because of the different bellhousings.
Originally Posted by rwenzing
There is very little info out there but here's what I have been able to find out from the shop manual and other sources:
Throughout the 90's and up through 2000, all Ranger manuals were M5OD-R1 made by Mazda, regardless of engine displacement. Besides internal ratios, the only other difference was in the outer cases which were different to match the individual engine bolt patterns (these transmissions have a bell housing that is integral to the transmission case casting).
In 2001, an upgraded Mazda trans called the M5OD-R1HD was introduced for use only with the 4.0L SOHC. The shop manual shows that the synchronizer blocking rings for first and second are different. The first gear ring is larger in OD and ID and the second gear ring is of a different construction. It stands to reason that the shift fork, synchronizer sleeves and the cones on the matching gears would be different to match the uprated rings.
Going only by the shop manual, it appears that the rest of the M5OD-R1HD transmission uses the same construction as the M5OD-R1. It would take a trip to a dealer parts counter to verify that all other internal part numbers are actually the same.
2001+ 2.3/2.5/3.0 continue to use the original style M5OD-R1 as in earlier years.
All 4.0L use a closer ratio gearset as compared to the 2.3/2.5/3.0 engines. It doesn't matter whether you're talking about 4.0L OHV or 4.0L SOHC, R1 or R1HD.