M50D-r1 variations discussion (not HD versions)

[Shran]

It is only the 4.0 transmissions that have different gear ratios. 2.3, 2.9, 3.0 have lower 1st, 2nd and 3rd ratios.

Gear	4.0	2.3, 2.5, 2.9, 3.0
1st	3.40	3.72
2nd	2.05	2.20
3rd	1.31	1.50
4th	1.00	1.00
5th	0.79	0.79
Reverse	3.40	3.40

It's a popular swap for 4.0 trucks if you're in need of deeper gears because it's like going one step lower in your axles (from 3.73 to 4.10, roughly.)

It is all or nothing, you have to use the entire gear set. The easy button is finding a good non 4.0 transmission and putting all of it into a 4.0 case. If you're buying parts new, you need an input shaft, countershaft, plus gears for 1st, 2nd and 3rd. I'm not quite sure why a different input shaft is required since the 4th gear ratio didn't change and IIRC it's even the same tooth count, but I digress, it's an easy swap anyway.

Here's another good thread:

Thread '2.5/4.0 M50D Hybrid'

Nov 13, 2009

My trans finally went out in my 4.0 4x4, so I decided now was the perfect time to try out an idea I had been tossing around. My truck has 3.73's with 33's, not as low as I would like, but better the 3.27's it came with. The 3.73's are nice on the highway though, and I drive 150 miles one way every weekend to and from school.

I was looking at the gear ratios for the M50D and I noticed that the 4.0 version is geared higher in first. second and third than the 2.5, 2.3, and 3.0 versions.

3.40 / 2.05 / 1.31 / 1.00 / 0.79 (4.0L Engines)
3.72 / 2.20 / 1.50 / 1.00 / 0.79 (All Other...

• PlumCrazy
• Replies: 21
• Forum: Transmission, Transfer Case, Hubs & Driveshafts

• 

 

[SenorNoob]

Since you posted here and are doing it semi professionally, ballpark price and timeline on dropping off a 4.0 4x4 transmission and picking it up later?

 

[SenorNoob]

Why is that funny PJ?

 

[PetroleumJunkie412]

Why is that funny PJ?

 

[AndrewM]

Since you posted here and are doing it semi professionally, ballpark price and timeline on dropping off a 4.0 4x4 transmission and picking it up later?

I haven't done one yet with the transfer case. I've been sticking mainly to the 2.3's, so I'm venturing a little out of my comfort with it.

Doing quick google search I found a build thread on this site on upgrading to the HD 4x4. https://www.therangerstation.com/tech/how-to-replace-a-m5od-r1-with-a-m5od-r1hd/#gsc.tab=0

Which led me down to a personal rabbit hole because one of my questions are answered in the original post. I've been getting in the HD versions (which I didn't think they would put in with 2.3's) and not realizing it, the shifter size and orientation and leads me to believe the same with the reverse synchro change.

I honestly have no idea how much or how long. I don't have anything for the transfer case or looked into one. I can give it a shot, but I'm just some dude on the internet. You can search for the transmission on fb market place and see my post and reviews.

 

[Shran]

Somebody needs to tear down an HD and a non-HD (I'll volunteer if someone wants to spot me a transmission ) and do a comparison on all the internals. Maybe that exists somewhere on the internet but I haven't seen it yet. I know there are some differences with certain synchros in the HD version but otherwise I am genuinely curious why it deserves the "HD" designation. You'd think it would be a BIG upgrade in strength or something but all the anecdotal evidence I've seen suggests that it's pretty much the same thing.

FWIW the shifter stub changed once in the mid-late 90's before the HD was a thing so for those interested, you can't ID these things by that alone.

I don't rebuild these for anyone other than myself but just guessing, I have at minimum a full day of labor involved plus some time ordering parts and CLEANING... that takes a lot of time by itself. A shop that has a heated parts washer can probably crank them out way faster than I ever could.

 

[AndrewM]

I don't rebuild these for anyone other than myself but just guessing, I have at minimum a full day of labor involved plus some time ordering parts and CLEANING... that takes a lot of time by itself. A shop that has a heated parts washer can probably crank them out way faster than I ever could.

Dude, right now I'm just power washing the outside (got hydraulic hose plugs for the speed sensor, and just trying not to get water in it as much as I can. Then tear down and brake clean the hell out of the inside.

I thought about using a metal trash can and stingers to clean the bodies themselves. I have a whole shop available, but can't have accounting approve a parts washer big enough to fit the trans body in.

I did clean one really well, primed and painted. It's a side project that keeps getting pushed back. I used latex aluminum primer, not sure I feel about it. It peels off really easy even with the paint over it. Not sure if I just want to start over with regular primer that won't peel.

 

[PlumCrazy]

Somebody needs to tear down an HD and a non-HD (I'll volunteer if someone wants to spot me a transmission ) and do a comparison on all the internals. Maybe that exists somewhere on the internet but I haven't seen it yet. I know there are some differences with certain synchros in the HD version but otherwise I am genuinely curious why it deserves the "HD" designation. You'd think it would be a BIG upgrade in strength or something but all the anecdotal evidence I've seen suggests that it's pretty much the same thing.

FWIW the shifter stub changed once in the mid-late 90's before the HD was a thing so for those interested, you can't ID these things by that alone.

I don't rebuild these for anyone other than myself but just guessing, I have at minimum a full day of labor involved plus some time ordering parts and CLEANING... that takes a lot of time by itself. A shop that has a heated parts washer can probably crank them out way faster than I ever could.

HD just means it has the extra bell housing bolt hole for the SOHC 4.0. I have mixed matched HD internals with non-HD. HDs are new enough to get the OSS in the 4x4 tail housing and the coated synchros, but the rest is the same as 95+ non-HD from what I experienced. I have built at least a dozen Frankenstein M5ODs now, and I just make sure I keep the R/5th gear stacks and shift fork a matched setup to avoid any compatibility issues.

 

[85_Ranger4x4]

Stub shaft and shift lever are indexed different for HD IIRC.

R2 is the same but indexed differently yet.

 

[Shran]

HD just means it has the extra bell housing bolt hole for the SOHC 4.0. I have mixed matched HD internals with non-HD. HDs are new enough to get the OSS in the 4x4 tail housing and the coated synchros, but the rest is the same as 95+ non-HD from what I experienced. I have built at least a dozen Frankenstein M5ODs now, and I just make sure I keep the R/5th gear stacks and shift fork a matched setup to avoid any compatibility issues.

Nice, that is great information. Thanks for chiming in here!

 

[PetroleumJunkie412]

HD just means it has the extra bell housing bolt hole for the SOHC 4.0. I have mixed matched HD internals with non-HD. HDs are new enough to get the OSS in the 4x4 tail housing and the coated synchros, but the rest is the same as 95+ non-HD from what I experienced. I have built at least a dozen Frankenstein M5ODs now, and I just make sure I keep the R/5th gear stacks and shift fork a matched setup to avoid any compatibility issues.

This is the most useful post I have read this year

 

[AndrewM]

HD just means it has the extra bell housing bolt hole for the SOHC 4.0. I have mixed matched HD internals with non-HD. HDs are new enough to get the OSS in the 4x4 tail housing and the coated synchros, but the rest is the same as 95+ non-HD from what I experienced. I have built at least a dozen Frankenstein M5ODs now, and I just make sure I keep the R/5th gear stacks and shift fork a matched setup to avoid any compatibility issues.

Oh....I get it. That's awesome to know.

I'm an AMC fan, own a '77 Gremlin. People want a Gremlin X over a "regular" Gremlin. The only difference from any AMC Gremlin and the "X" is the trim has an X on it (exterior hockey stick decal, steering wheel, glove box). That's it. Not the V8 upgrade or quad barrel or actual interior upgrade options.

 

[Li'l Work Truck]

This is the most useful post I have read this year

 

[PlumCrazy]

Stub shaft and shift lever are indexed different for HD IIRC.

R2 is the same but indexed differently yet.

The indexing changed a few times over the years with both R1s and R2s. You can mix and match as long as you pay attention to the length. The 4.2 R2 is the only true oddball. It's longer than all the rest (that's why a standard Hurst base won't work)

95 model year is when the R1 got the taller tower. That's why the Hurst came with 1/4" spacer. To use it on the older short tower.

IIRC all of the SBF R2 variants have the same length as the 95+ R1

 

[85_Ranger4x4]

I didn't know the R2 was ever the same as the R1

I ground a new flat on my stub shaft so I could use a chrome FX4 Ranger shifter on it. Shaft is the same diameter is an R1.