I found an answer to my own question in the service manual but can't find a way to delete this thread.

 

Why delete it? Someone will be wondering and find this thread.

Mazda M5OD transmission - Wikipedia, the free encyclopedia is what should be in there. It was then changed to a HD unit when they went from the OHV motor to the SOHC motor

 

I thought the admin might delete it for me. But yeah, I should explain for anyone looking with the same question.

A listing for a seal for my 2010 Ranger's transmission at Rock Auto said it was for a M5HD, but I had heard my truck has the M5R1, so it got me wondering which transmission is in my truck. Then I found that on the door sticker the transmission code is "R". That had me stumped so I posed the question on here.

I ended up finding the answer in my 2010 owner's manual (DOH!) and code R is for the M5R1, and code J is for the M5HD.

I think Rock Auto was maybe listing the transmission for my truck wrong on the part I searched because the same part might fit both transmissions. At the same time it was confusing to see the wrong transmission listed for my truck because I had put in my correct year, model, and engine size.

 

Should be the same only difference is the HD has a different first gear ratio for the 4.0's torque other than that their identical.

 

Like pearl said and I said, the trans was modified for HD due to the extra torque from the OHC motor.