Transmission Options

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Nov 14, 2016 | 02:08 AM

#16

RichS2659

Cargo Master

Joined: Feb 2006

Posts: 3,012

Likes: 251

From: North Pole, Alaska

Are you going to use your F-250 as a car or a truck? As a truck, an NV-4500 would be the best way to go as it would basically give you the option of two First gears like your NP-435 while still having the OD gear compared to the TKO. It can also use your mechanical clutch linkage. Another option for an FE is to use a SBF pattern ZF-5 with an adapter from Bentsen's, but a ZF uses a hydraulic clutch which you would have to retrofit. It might be cheaper to change your gearing to a 3.54. I think that 3.31's are unobtanium filled. That is what Ford did. I have a 79 F-250 4wd with a 400/T-18/ 3.54's in the backyard.

Nov 14, 2016 | 07:47 PM

#17

1972RedNeck

Logistics Pro

Joined: Feb 2011

Posts: 3,522

Likes: 11

From: Townsend, MT

Quote:

Originally Posted by RichS2659

I think that 3.31's are unobtanium filled.

I just snagged a Dana 61 axle with 3.31's off Craigslist for $250...

Nov 14, 2016 | 11:45 PM

#18

Mike in Ohio

Senior User

Joined: Dec 2007

Posts: 178

Likes: 0

Quote:

Originally Posted by 1972RedNeck

I doubt it is 3.63 but should be close (3.54ish maybe?).

I prefer to gear my rear end to where I want my overall ratio and then gear the tranny/t-case down for whatever first gear ratio I want. That way you don't have to have the parasitic loss from O/D.

It still has the metal tag on the diff, I will have to crawl under and look again. It has been a while and I may not be remembering correctly. It seems to be revving pretty high at 60 mph but I have no tach so it might just be in my head.

Nov 18, 2016 | 10:14 AM

#19

JEFFFAFA

Hotshot

Joined: Mar 2013

Posts: 14,255

Likes: 199

From: Phoenix, Az.

Quote:

Originally Posted by Mike in Ohio

I think my rear end is a 3.63.

1966/72 F250 Dana 60......29 spline axles...3.54 ratio.
1966/72 F250 Dana 60......29 spline axles...4.10 ratio.
1967/72 F250 Dana 60......29 spline axles...3.73 ratio.
1967/72 F250 Dana 60......29 spline axles...4.56 ratio.

3.73 the popular axle in a 68 F250.

Nov 18, 2016 | 11:02 AM

#20

willowbilly3

Post Fiend

Joined: Jun 2003

Posts: 8,209

Likes: 12

From: Black Hills of SD

Quote:

Originally Posted by 1972RedNeck

That's my theory too but it's a tough one to make most people comprehend. I had a big go around on AHTS forum a few years ago about the efficiency of having your top gear a direct power path through the transmission (in a big rig). Met with adamant ignorance. In a light truck, like most pickup owners on this forum that won't ever tow, it's probably not much of an issue considering the limited choice of any transmissions with direct high other than the old Clark 5 speed.

Also to the op, the later 460 ZF isn't a bolt up to the newer style 460. But it's almost worth changing engines to use the ZF 5 speed, it's a great transmission IMO.