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M5OD transmission hybrid- New findings and new gearing.

94Sport5

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Sorry if this isn't posted in the right spot, but my explorer is a basically stock first gen lol.
Well I'll start by saying, that replacing the transmission on a 94 explorer sport with the front end raised on jackstands is no easy task. It's a great experience though and when everything works you sure do feel proud of yourself! Another thing is you certainly CAN, at least on a sport, remove and install the transmission without removing any part of the exhaust...you just have to have the transmission jacked/lifted up as high as possible, like the top of the bellhousing touching the top of the trans tunnel high, while turning it and having someone pull on the tail housing while you push on the bellhousing, it absolutely will fit over the exhaust, coming out and going back in, but just barely. Just wanted to clarify that as so many people say different things about it. I also have no suspension mods done, but have heard sports sit one inch higher than 4 doors which might make a difference. Anyways, the point of this post is to give my experience with building a "hybrid" m5od 4x4 transmission.
I had made a post earlier this year concerning my findings with two different transmissions. Upon buying a listed 2.9 4x4 m5od on eBay, I thought I had it made by being able to put it in with no fuss..only to find out the bellhousing was for a 3.0 ranger, not a 2.9. So at that point, my journey started, knowing I had to take the internals out of the rebuilt 3.0 transmission. After doing so, and counting gear teeth on the input and countershafts I came to a pretty odd, but not impossible finding. The 3.0 transmission I bought had 4.0 gears with a 2.9/3.0 countershaft, and the old transmission I had in the truck originally laying around was rebuilt in the past with a 2.9 gearset, but had a 4.0 countershaft in it. Admittedly baffled by these findings, I got my bearings straight (in my head) and tried to simplify how they even worked together.
I started reading up on gear meshing after numerous "genius" mechanics told me it was impossible for them to work that way and the transmission would grenade itself since the 2.9/3.0 countershaft and 4.0 countershaft have different tooth counts, made specifically for their gearsets. So I took it upon myself to mock up the gearsets in an empty m5od case and see what was up. First I mocked up the new 4.0 gearset (from the 3.0 housing) and old 4.0 countershaft (from old transmission) and the meshed shifted and worked perfectly as they should. I then did the same with the old 2.9/3.0 gearset (from old transmission) and new 2.9/3.0 countershaft, again everything meshed shifted and worked perfectly as it should have. Then I took the differing countershafts and swapped them between BOTH 2.9/3.0 AND 4.0 gearsets, as they apparently originally were, and of course again, they worked fine.
So after finding all this out and after reading up on the 2.9/3.0 gearset behind the 4.0 ohv engine on all types of forums with differing opinions..including you will hate the steeper gearset with the 4.0 etc, and others saying they love it but it's a little much, I ended up deciding to use the new 4.0 gearset with my old but virtually flawless looking 2.9 countershaft. Oddly enough, it has a physically wider first gear than the 4.0 countershaft's first gear, which may also mean that it's stronger. I do have a pic of the difference. I calculated the ratios this hybrid transmission would have, using the new 4.0 gears & 2.9/3.0 countershaft together, and determined this combination to have 1-3 gearing of: 3.61, 2.13, 1.39, -vs- the 2.9/3.0 combination of 3.72, 2.20, 1.50..and the 4.0 combination of 3.40, 2.05, 1.31. As you can see, they are better ratios than the 4.0 trans gearing, especially first gear, and that it's actually right in the middle of both transmissions..so I thought they best of both worlds possibly right?

True Hybrid transmission 4.0 gears/2.9 countershaft
1st: 3.61:1---1.48 spread to 2nd--.21 more gear than 4.0 transmission
2nd: 2.13:1--.74 spread to 3rd---.08 more gear than 4.0 transmission
3rd: 1.39:1--.39 spread to 4th---.08 more gear than 4.0 transmission
4th: 1.00:1

2.9/3.0 m5od

1st: 3.72:1---1.52 spread to 2nd--.32 more gear than 4.0 transmission
2nd: 2:20:1--.70 spread to 3rd---.15 more gear than 4.0 transmission
3rd: 1:50:1---.50 spread to 4th---.19 more gear than 4.0 transmission
4th: 1.00:1

4.0 m5od/hd

1st: 3.40:1---1.35 spread to 2nd
2nd: 2.05:1--.74 spread to 3rd
3rd: 1.31:1---.31 spread to 4th
4th: 1.00:1

As you can see I kept the close ratio style of the 4.0 transmission by simply increasing the gearing of 1-3 with a countershaft with more teeth. After a long week of working on it mostly by myself after work, I replaced the flywheel, clutch & pressure plate, pilot bearing, slave cylinder & master cylinder, put in my newly rebuilt by myself hybrid transmission and bled the new clutch system. The master was pre bled so that helped quite a bit, because I had it bled totally in less than 10 mins.
Everything works flawlessly. There's not a lick of noise, it's very smooth and I must say, 1-3 are incredibly peppy now! Even though it looks on paper like such a minor difference, where the rpms are when I shift into second and third are in such a perfect spot for optimum torque that it feels like a completely different truck! It's much faster than before and I don't have to push on the pedal as hard to accelerate. I have about 200 miles of city driving on everything now and I'm so proud that it's finished and is working right.
I originally wanted to do this "hybrid" solution after the truck's 3.27 gears started getting to me, but boy is this a decent combination! I can't wait until my 4.10s are installed, I can see/ tell it will be so much better and still won't be too much gear especially when I move on to 31x10.5s or even 32s if they will fit with minimal cutting. Well..if any questions go ahead and ask! Rebuilding the m5od and then installing it by yourself I feel gives a great bit of experience, and if I can help anybody else out then I will! Everything is still very fresh in my mind lol.
 



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RangerX

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I vaguely recall your previous post on this, how great to hear this final result!
 






94Sport5

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I vaguely recall your previous post on this, how great to hear this final result!
Thanks a lot! My original post had me just as baffled as all the techs from different shops I tried to talk to. After reading up on the gear meshing, I found out that it's the tooth depth as well as the shape and curvature that allow gears to mesh correctly..not the number of teeth...to a certain point.
One shop guy got all smart with me and said hey if you ever happen to get it done, stop by so I can see it with my own eyes, and then pretty much hung up on me..being in over his head with work in his small shop he acted like I was saying impossible things and wasting his time..lol. So I have been wondering if it's worth the time stopping by showing him, not only as proof, but for educational purposes..and mostly prove that things aren't as impossible as some try and make it seem.
 






Fix4Dirt

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Sorry if this isn't posted in the right spot, but my explorer is a basically stock first gen lol.
Well I'll start by saying, that replacing the transmission on a 94 explorer sport with the front end raised on jackstands is no easy task. It's a great experience though and when everything works you sure do feel proud of yourself! Another thing is you certainly CAN, at least on a sport, remove and install the transmission without removing any part of the exhaust...you just have to have the transmission jacked/lifted up as high as possible, like the top of the bellhousing touching the top of the trans tunnel high, while turning it and having someone pull on the tail housing while you push on the bellhousing, it absolutely will fit over the exhaust, coming out and going back in, but just barely. Just wanted to clarify that as so many people say different things about it. I also have no suspension mods done, but have heard sports sit one inch higher than 4 doors which might make a difference. Anyways, the point of this post is to give my experience with building a "hybrid" m5od 4x4 transmission.
I had made a post last year concerning my findings with two different transmissions. Upon buying a listed 2.9 4x4 m5od on eBay, I thought I had it made by being able to put it in with no fuss..only to find out the bellhousing was for a 3.0 ranger, not a 2.9. So at that point, my journey started, knowing I had to take the internals out of the rebuilt 3.0 transmission. After doing so, and counting gear teeth on the input and countershafts I came to a pretty odd, but not impossible finding. The 3.0 transmission I bought had 4.0 gears with a 2.9/3.0 countershaft, and the old transmission I had in the truck originally laying around was rebuilt in the past with a 2.9 gearset, but had a 4.0 countershaft in it. Admittedly baffled by these findings, I got my bearings straight (in my head) and tried to simplify how they even worked together.
I started reading up on gear meshing after numerous "genius" mechanics told me it was impossible for them to work that way and the transmission would grenade itself since the 2.9/3.0 countershaft and 4.0 countershaft have different tooth counts, made specifically for their gearsets. So I took it upon myself to mock up the gearsets in an empty m5od case and see what was up. First I mocked up the new 4.0 gearset (from the 3.0 housing) and old 4.0 countershaft (from old transmission) and the meshed shifted and worked perfectly as they should. I then did the same with the old 2.9/3.0 gearset (from old transmission) and new 2.9/3.0 countershaft, again everything meshed shifted and worked perfectly as it should have. Then I took the differing countershafts and swapped them between BOTH 2.9/3.0 AND 4.0 gearsets, as they apparently originally were, and of course again, they worked fine.
So after finding all this out and after reading up on the 2.9/3.0 gearset behind the 4.0 ohv engine on all types of forums with differing opinions..including you will hate the steeper gearset with the 4.0 etc, and others saying they love it but it's a little much, I ended up deciding to use the new 4.0 gearset with my old but virtually flawless looking 2.9 countershaft. Oddly enough, it has a physically wider first gear than the 4.0 countershaft's first gear, which may also mean that it's stronger. I do have a pic of the difference. I calculated the ratios this hybrid transmission would have, using the new 4.0 gears & 2.9/3.0 countershaft together, and determined this combination to have 1-3 gearing of: 3.61, 2.13, 1.39, -vs- the 2.9/3.0 combination of 3.72, 2.20, 1.50..and the 4.0 combination of 3.40, 2.05, 1.31. As you can see, they are better ratios than the 4.0 trans gearing, especially first gear, and that it's actually right in the middle of both transmissions..so I thought they best of both worlds possibly right?

True Hybrid transmission 4.0 gears/2.9 countershaft
1st: 3.61:1---1.48 spread to 2nd--.21 more gear than 4.0 transmission
2nd: 2.13:1--.74 spread to 3rd---.08 more gear than 4.0 transmission
3rd: 1.39:1--.39 spread to 4th---.08 more gear than 4.0 transmission
4th: 1.00:1

2.9/3.0 m5od

1st: 3.72:1---1.52 spread to 2nd--.32 more gear than 4.0 transmission
2nd: 2:20:1--.70 spread to 3rd---.15 more gear than 4.0 transmission
3rd: 1:50:1---.50 spread to 4th---.19 more gear than 4.0 transmission
4th: 1.00:1

4.0 m5od/hd

1st: 3.40:1---1.35 spread to 2nd
2nd: 2.05:1--.74 spread to 3rd
3rd: 1.31:1---.31 spread to 4th
4th: 1.00:1

As you can see I kept the close ratio style of the 4.0 transmission by simply increasing the gearing of 1-3 with a countershaft with more teeth. After a long week of working on it mostly by myself after work, I replaced the flywheel, clutch & pressure plate, pilot bearing, slave cylinder & master cylinder, put in my newly rebuilt by myself hybrid transmission and bled the new clutch system. The master was pre bled so that helped quite a bit, because I had it bled totally in less than 10 mins.
Everything works flawlessly. There's not a lick of noise, it's very smooth and I must say, 1-3 are incredibly peppy now! Even though it looks on paper like such a minor difference, where the rpms are when I shift into second and third are in such a perfect spot for optimum torque that it feels like a completely different truck! It's much faster than before and I don't have to push on the pedal as hard to accelerate. I have about 200 miles of city driving on everything now and I'm so proud that it's finished and is working right.
I originally wanted to do this "hybrid" solution after the truck's 3.27 gears started getting to me, but boy is this a decent combination! I can't wait until my 4.10s are installed, I can see/ tell it will be so much better and still won't be too much gear especially when I move on to 31x10.5s or even 32s if they will fit with minimal cutting. Well..if any questions go ahead and ask! Rebuilding the m5od and then installing it by yourself I feel gives a great bit of experience, and if I can help anybody else out then I will! Everything is still very fresh in my mind lol.
WOOOOOOO!!!!!!!!!!! great thread!!!!!! highly informative! like bill, i recall your original post, glad to hear the results!
 






94Sport5

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WOOOOOOO!!!!!!!!!!! great thread!!!!!! highly informative! like bill, i recall your original post, glad to hear the results!
Thank you thank you! Let's hope this clears up some cloudy information people have read regarding this swap!!
 






Nadams01

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Nice info, you gotta think like ford sometimes when it comes to parts interchangeability. Why would they design a completely different countershaft just for the 4.0 when it makes similar power to the old 2.9/3.0, that would cost millions of dollars in R&D and production. Its never good to assume, but money makes the world go round and its no surprise ford wouldn't change that small detail for a minor engine bump. I like the customization we have with the m50d now, can really change some stuff up in terms of gear ratios, and those 4.10 gears are gonna make a big difference compared to 3.27.
 






Brian1

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Interesting info! Thanks for this follow-up post. I can definitely see the advantage from a driveability standpoint of going the true hybrid route. From a rock crawler standpoint though I think I would still go with the lowest set. Did you happen to measure any backlash of the gears between the different combos?
 






94Sport5

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Interesting info! Thanks for this follow-up post. I can definitely see the advantage from a driveability standpoint of going the true hybrid route. From a rock crawler standpoint though I think I would still go with the lowest set. Did you happen to measure any backlash of the gears between the different combos?
Yes I agree for the lowest possible ratio for a rock crawler, but at least we have even more options now!
I did at least visually and by feel, get a solid idea of backlash between the different gear combinations before and after installing..and found that the newly rebuilt set, which was the one I originally got a feel for and checked out had slightly less backlash, but hardly any at all, than my old transmission before I took it apart.
The old transmission had very minimal backlash as it was for being ran for as long as it did. Putting the different gear combinations in a fresh case had virtually the same backlash as the already put together rebuilt unit did, so I went with it! Even the full 4.0 set had the same backlash as the full 2.9 set.
These gears are very hard and high quality and I think that as long as the trans is filled with lube and not bleeding it out the back.. and nothing catastrophic happens, that the gears actually get very minimal wear even over a hundred or so thousand miles of driving.
 






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