Drive shaft choice

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Nov 13, 2022 | 10:44 PM

curdogstation

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Trailering

Joined: Jan 2022

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Drive shaft choice

I have an 85 short bed regular cab 2wd f150 that I put an axle under to convert it to 4wd. Bought a divorced np205 from a 74 and I’m currently looking for a 2wd ZF5 to mate to that transfer case. Problem is, I’m having trouble determining what type of driveshafts to use for the rear and tranny-Tcase shaft. Obviously has to be slip yoke in the rear but what type and what would be best to put in between the transmission and T case?

Jan 20, 2023 | 05:24 PM

2001F350dualwheel

Fleet Mechanic

Joined: Nov 2015

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You’re most likely gonna have to either make a custom driveshaft or get a short pre-made one maybe from a older Ford truck that accepts the u joint sizes that are used by the existing trans and the t case and then measure and mount the t case where the pre-made driveshaft ends up locating it. There were some 70s F150s short bed single cab with divorced t cases…yiu may be able to use those driveshafts if they use the same u joints. Your biggest issue is gonna be the comparability of the current u joints to older driveshafts and that short wheelbase will lengthen one driveshaft and shorten the other that go to the axles depending on where the t case is located. I know divorced cases can sit back quite a bit depending on the chassis length and it makes the front driveshaft super long.

another thing you can look into is what’s called a double cardan joint. It’s basically about as short a distance I can think of to locate the divorced t case somewhere reasonable. I don’t know your clearances on the trans and t-case outer casings.