What transmission is in your truck now? Is it the grany low 4spd or the light duty 4spd. If it's the grany low 4spd you've already got one of the toughest transmissions Ford put in the pick ups. If it's a grany low 4 spd it's either the BW T-18 ( cast iron transmission to cover with a screw on shifter retainer ) or a NP435 ( aluminum top cover, push down and twist shifter retainer ) . So if it was me I would just add an O/D unit of one kind or another. The AA Ranger box goes in front of the transmission. The down side is it will move the stock shifter back 7 1/2". Which mean you also need to move the transmission crossmember back 7 1/2". And you also need to shorten the driveshaft.


I don't remember what size the bearing retainer is on the T-18/NP435. It would be one of the two below.


(P/N 760010M-27) | Advance Adapters

(P/N 760014M-27) | Advance Adapters



The other choice would be something that mounts behind the transmission like a gear vendors/Us gear OD unit. They aren't as strong as the AA Ranger box, but they don't require moving the stock transmission back. And unless you find a good used one they are very expensive. And I think US gear went out of business.

Or there is the a medium duty auxiliary transmission like a Brown/spicer unit. But that a little bit of over kill for an F100. Not to mention heavy!

 

I was thinking gear vendors and OD units were like $1500?

 

The AA Ranger OD box is just over $1300.

The Gear Venders OD, new will run $3000-$3500.

 

Dang!!!

 

There was a guy (madmanmax?) who'd posted his entire T5 swap in a webpage. Unfortunately...its no longer up (or at least i can't find it.)

his story went like this:
no need for the new flywheel, etc- just unbolt the 3-speed from the bellhousing, and put the T5 in its place. some crossmember modification and driveshaft shortening may be required.

seemed really simple- the caveat being that you won't be doing any heavy hauling in it.

the world-class T5s are rated for ~300ft-lbs.

 

The T-5 has a different bolt pattern then the 4 speed.

And remember there is a difference between it surviving in a light car and a heavy truck.

 

Didn't they use the T5 behind high horsepower cars? I think that was what was in my 85 Mustang but, it was a stock 5.0.

 

you are absolutely right, thank you for reminding me. 'madmanmax' was using an adapter plate between the T5 and the 300 bellhousing. that also took care of the issue with the T5 having a longer input shaft. the plate was about $100.

sorry for leaving that out of my original post, my memory is terrible...