M50D-r1 variations discussion (not HD versions)

[AndrewM]

Okay guys, new member here but long time Ranger owner.

I fell into rebuilding the r1's and it's getting a little out of hand but chugging away. I have been noticing differences that I can't find anywhere that denotes these differences and curious if anyone knows why/when they changes were made. It makes it a little difficult answering questions from people. I don't know if I have your exact version on hand without lots of pics.

First is reverse was updated at some point. The first picture shows two different amount of teeth for the synchros, also the size of the gear, fork, keys are all different.

Second pic is the top plate is a different height, easy to tell by looking at the pins. Making shifter balls different lengths as well. Along with the shifter balls being different height, there's different configurations of them as well. Some have the flat spot for the shifter facing towards the passenger side while others have the flat spot faces towards the front.

Last pic is just some goodies I've been sourcing. There's a few things I can't find new anywhere, just small bs like the speed sensor clip. Got tired of dropping the little bearings in on the floor and chasing them, used my micrometer to measure and ordered bags from McMaster Carr. I can't find a good source of the spring in the 5th/R fork. I can get close to the exact size, but not what I think would be good enough. The pin in the top plate that engages R lights, I've sourced them from McMaster Carr as well, not paying $20+ for one. Got a rod that fits perfectly and able to cut and mill them to OEM standard.

Oh, before anyone says something. Yes these are the old nuts holding everything together. I'm still making sure this one is built right before I put on the new ones and indent them into the key way.

I've done about a dozen of these things so far and the thing I noticed is the front shaft/4th gear gets ate up all the time. I got lots of pics of stuff I've found tearing these apart for people, if anyone wants to see them. 4th gear and its pilot bearing are top prospects for problems from what I've seen so far.

 

[Jazzer]

Welcome to TRS, Andrew. Interesting and valuable subject there.

Out of curiosity, what is the ball bearing size and is it consistent across the years?

 

[AndrewM]

Welcome to TRS, Andrew. Interesting and valuable subject there.

Out of curiosity, what is the ball bearing size and is it consistent across the years?

Yes, they have been consistent with all these. I want to say the oldest I have done is '89 and the newest is '05 (some slop with me guessing)

The 5th/R fork (spring and ball keep it in gear) and main tail shaft (that hold 5th gear hub) are 5/16". Speed sensor 1/4".

 

[Shran]

I rebuilt one for my '88 (uncommon 2.3 powered 4x4 truck) and it had the original style 5th/reverse parts. IIRC it was the synchro for one or both gears had a different # of teeth or something like that. Why the change, I don't know and it changed after only a year or two.

Another thing I have noticed is that sometime in the late 90's, the dog teeth on most of the forward gears changed from a pointed triangle to an angled triangle.

Most of the broken ones I've taken apart have a destroyed input shaft and countershaft too. A couple have had the large flange piece broken off the input shaft where it is welded on. Some including ones that I have rebuilt have had pocket bearing failures there. Personally I think the OEM bearing was pretty good but susceptible to low oil damage for obvious reasons and the aftermarket replacements are cheap junk. I haven't been able to dig up a Mazda or Ford part number for that bearing, I would like to see if I could find a very high quality replacement instead of the ones that come in bearing kits. Anyway I think the input/countershaft failures are a combination of factors.

Thanks for the info on the ball bearing, I actually needed to know that.

Last comment from me for the moment: The oil slinger that sits in the front bearing retainer, visible in your second picture: do you see them installed as you have it positioned (gold side facing the transmission) or the other way around? The Ford manual I have has it facing the way you have it. I have seen them both ways though! And there's a machined lip on the bearing retainer that it fits over perfectly if you flip it around. I don't trust things I've found inside unknown transmissions but I also don't 100% trust shop manuals either and both ways of installing it seem plausible.

 

[AndrewM]

Last comment from me for the moment: The oil slinger that sits in the front bearing retainer, visible in your second picture: do you see them installed as you have it positioned (gold side facing the transmission) or the other way around? The Ford manual I have has it facing the way you have it. I have seen them both ways though! And there's a machined lip on the bearing retainer that it fits over perfectly if you flip it around. I don't trust things I've found inside unknown transmissions but I also don't 100% trust shop manuals either and both ways of installing it seem plausible.

I'd like to state for the record, I'm not expert either. lol

But what I have experienced is that the gold side is faced inwards towards the gears. The spacer that keeps the front shaft outside bearing race in spec (thrust play) has two different sides. That spacer has a smooth side and a shoulder side. The shoulder side fits that oil seal perfect.