I want to put a M5OD in my 1981 f-350 4x4 400 cu 4spd. It has 4.11 gerars and I was wondering how much of a difference swapping my t-18 for a M5OD. I really want the 5th gear. Currently i hardly use my 1st gear cuz its too low. BUt its nice when i want a lot of low end torgue. Should I swap them? and what will be the major losses when i swap to the 5 spd. Will i loose a lot of low end torque? Or is the M5OD like the t-18 but with an "over drive"? It would be very nice to have a 5th gear or an over drive to reduce the RPM's on the highway. Im on the highway 1/2 the time and other half in the the mud What to do???????

Billy

 

The M5OD is pretty weak doesn't have a great reputation behind even 300 and 302's. Plus the 400 has a big block bellhousing and the M5OD won't fit it anyway. If you really need overdrive, I would swap in a ZF 5 speed instead. You won't lose the low first gear with this tranny either.

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1995 F-150 Supercab XLT 155" 4x4 M5OD 302
1986 F-150 4x4 NP435 300

 

What is the availability of a ZF5? Do you have one in your truck??

Billy

 

The availability is kinda scarce. If you find an F-250 or 350 with a 460 and 5-speed, this is the tranny it's got. I think they started using them around 91. I helped a friend put one of these trannys into his Bronco, and everything bolted up nice. The low first gear isn't rediculous, like an NP-435, but it isn't too high, like most 5-speeds. The gear spacing is really good too, without a "dead gear".

Jared