2.9 convert

[Woody88]

Hey guys,
I found a m5r1 on a 2.9 thats 2 wheel and I have a 4x on a 4.0 that is pooched. I was wondering if i could take the tail end off the 2.9's and swap it with the tail end of the 4x4? the 2.9 m5 is in a 94 ranger and mine is a 91 explorer. it looks to me like the bolt patters are the same where the tail of the 2x bolts to the main tranny body and where the 4x bolts to the main, I know also the tailshaft is diff on the 2.9 but if this did work that would solve that right? no 100% on the patters of bolt cuz i did but a glance but i thought id consult the experts

Thanks ahead of time, Cody.

 

[MAKG]

No, if the MAINshaft is different, putting a different adapter on the back will not solve that.

This is usually asked by people who have never disassembled a transmission. Get the correct one or you'll have a workbench covered with 50 doorstops. Not that this is a difficult transmission (it isn't), but you don't have any idea what you're getting into.

 

[Woody88]

would it be possible if they were both from a 4.0?

 

[Woody88]

and your right I've never taken a tranny apart, I want too but i was intimidated but i think im going to print off the exploded diagram and such and take it slow.

 

[Jspafford]

No, the 2WD and 4WD trucks use a different main shaft. Now, if it were a 4WD transmission from a 2.9L it would work. No 2WD transmission will work without extensive teardown.

 

[AllanD]

To do what you are proposing involves complete teadown of BOTH transmissions.

And being honest taking them apart isn't so bad, the biggest newbie
mistake when disassembling a mazda trans is taking stuff apart that you don't NEED to take apart.

the second mistake? mixing up parts that need to be used as a set because of compatibility issues.

Yes, it's possible, I do exactly what you are proposing in about 6hrs,
I did one just like that monday.... but it wasn't my first rodeo...

the other thing is being able to tell a "bad" part from a "good" part.
Any idiot can identify a part that's totally "smoked", it's identifying
the part that's going to explode next week that's a bit harder.

That being said disassemble the "poached" one first, that way
you have little to lose...

And besides, if the pilot snout on the main/output shaft where it sits in the "pocket" bearing in the backside of the input gear is bad you cannot build one "good" trans out of the one bad one and one wrong one you have available to you.

you NEED a good 4x4 output shaft.

AD

 

[Woody88]

alrighty then thank you very much guys, my bad, i will try to learn the ways of the transmission.

 

[Woody88]

hey Jspafford i found a 4x 2.9 m5, so that would work if i swapped out the extension housing?

 

[Jspafford]

Huh? If it is a 4WD trans and you are putting it in a 4WD truck it will work regardless of if it came from behind a 2.9L or a 4.0L, no need to swap anything. The gearing is a tad bit different, but you won't notice much.

 

[Woody88]

oh yea..sorry im an idiot, will it be weaker since it was behind the 2.9 instead of a 4.0? due to a less powerfull engine?
and thanks for the feedback even though the majority of questions are stupid

 

[Jspafford]

Will the transmission be weaker? No, unless you have an upgraded transmission in the truck already. They are the same other than the gear ratio's.

AllanD will chime in and correct me if I'm wrong.

 

[Woody88]

Would I be able to use a FM146? instead of the M5

 

[MAKG]

Yes, but I wouldn't unless it was freshly rebuilt AND free.

 

[AllanD]

Will the transmission be weaker? No, unless you have an upgraded transmission in the truck already. They are the same other than the gear ratio's.

AllanD will chime in and correct me if I'm wrong.

I am running a "wide ratio" 2.9 trans behind my 4.0.

And notwithstanding the fact that I tell everyone that 4.0's can get a bit "breathy" at the top of third gear when towing up a steep hill
(or atleast my brother's did) my 4.0 which being "nice" has 1/3 the
miles on it, 4.10 gears and headers (borla) and frankly I haven't wowed anything with it on any hills I could find where I couldn't climb the hill in 4th with the cruise control on.

Will it break? Unlikely the inards of this particular transmission
are the guts from a 2003 3.0 trans with the assymetrical
synchro teeth and the carbon friction surfaced synchro rings
and I'm generally "nice" to it...

I've got a 4.0 trans that I do plan on swaping in when I finish
"holy stoning" it, but I'm in no particular rush... it'll be another 4+ months before weather will allow me to install it.

AD