Clarification on Duratec 5 speeds. Please

[stan]

I've read through about 10 pages in the Transmission forum. Went through the tech library. Searched other online sources (but this Forum is the best, obviously). What I'm seeing: The 5-speed (M50D-R1) from '88 and newer can be used in any 2.3/2.5 Lima or Duratec. There is no bellhousing so the transmission from the 3.0 can't be used even though it's the same transmission. But the internals can be used. The transmission from the 4.0 -'86 and newer (?) is the same except for the gear rations. (I'm assuming they're lower because of being used in 4X4s and more towing expectations).

Sorry for the long lead in. I'm looking to replace my '01 Duratec 5-speed and then rebuilding -maybe- my old one. It has the 2nd gear syncro going out and don't want to get an earlier one and find out it doesn't work.

Thanks for any input, and hopefully not TL;DR

 

[pjtoledo]

I've also heard the innards are the same and have a couple to experiment with but haven't actually swapped parts yet.
4.0 has more low rpm power, does not have as low 1st & 2nd
2.3L, 2.5L, 3.0V, 2.3D all have less power, do have lower 1st & 2nd 3rd?

Duratec have their own bell housing pattern, no others will fit.
for what it's worth, my 2005 Duratec still has the original transmission at 377,000+ miles.