Highboy help

[gonzalo medina]

Highboys were all manual right? Is there anyway to make one automatice? I hate or let me rephrase can't drive those old 3-4 speed trucks. there just to much for me. I would like a highboy though, is there anyway of getting the best of both worlds? THANKS

[72hiboy4x4]

with a divorced transfer case, and a custom driveshaft, it should be pretty easy to convert a truck to auto..........


And also,
a column or a way to shift it
custom (?or a modified factory?) tranny crossmember
speedo cable to match
tranny cooler in the radiator and lines to match

[460 crew]

The crossmember only has to be moved and inch or 2 to accommodate the C6. If your lucky and can find a 4x4 C6 with a short 4x4 tailshaft would make your life alot easier. But if not I'm sure the custom driveshaft would work for you. With the stock stuff you can find driveshafts for the auto application quite frequently. FordFool was thinking of going to an auto in his 4x4 crew and found out the tailshafts are pretty hard to come by. There is alot of members here and someone might come up with something if you post in the wanted.

[gonzalo medina]

I have access to tranny shops who stock 4x4 c6's for big or small blocks I just wondered about the drive shafts. I'll ask around and see if they could make some to accommodate the changes. Looking to start a new 4x4 project soon guys's.

[averagef250]

I've got 3 short shaft 4x4 FE C6's laying in the rain and atleast one factory center driveline for an auto. These are from '73-'77 trucks of coarse, automatics, power steering and power brakes did not seam to be an option in the bumpside highboys. You can put a 4x4 steering shaft in a 2wd auto column and make it look factory.

Another option is to go with a later model mated C6 and 205 and switch to a 78-79 high pinion front axle.

[72hiboy4x4]

would a 2wd long shaft tranny work in there? Thats what I was thinking of in my first post, cause thats the way I would have done it. Cheap, easy, probably what I could find for free

[furray]

No, there wouldn't be enough room for the driveshaft.

[averagef250]

Even the short C6 is quite a bit longer than a 435. The long one makes for a 10 inch or so center driveshaft and the long shaft version uses a slip yoke instead of a fixed yoke output. I'm sure you could rig it to work, but it would not work well.

I was very unaware there was such a demand for highboy auto trannies. Seams around these parts atleast that the automatic trucks are always the first to die and get parted.

[Gittinwidit]

I took measurements and could have sworn a 2wd c6 would fit with drive shaft modifications? I was planning on doing the same and shortening my shaft. I swear I know it will fit! I'll measure again this weekend cause I'm doing the same thing.
My only concern was the boss for the T-case shifter handle. Figured that would be an easy fab and would cross that bridge when I got there.
I can take pics but I know it will!

[averagef250]

That center driveline takes pretty good abuse and has some pretty important drivetrain angles associated with it. Making it shorter increases U-joint angles considerably and as many know, makes for exponentially shorter U-joint life.

You can use a 2wd C6, but it must be the short shaft version with the fixed yoke. If you can't find the 4x4 tailshaft housing with the t-case shifter bosses you can easily take a 2wd tailhousing to a welding shop and have some bosses put on it.

I'm not an expert on ford production, but I've owned alot of bumpside highboys and have a good amount of factory literature and power steering and auto transmissions surely don't seam to have been an option on our trucks. Factory Ford chassis manuals have very in depth drivetrain angle specs for every different model truck with all the different engine and tranny options available and the only transmission listed for an F-250 4x4 from 67-72 is a 435 4 speed in my books.

[Gittinwidit]

Sorry to hyjack your thread gonzalo. On same topic!
But I have a short shaft C6 that has 4 bolts sticking out the tail on a plate to attach to a driveshaft instead of a yoke. It came from a 69 F100. Anyone know if the 4 bolt thing will come off to put on the yoke from the NP435? I looked at it the other day after this question came up and couldn't figure it out without wrenching.

Just thinking about this again... Something I didn't measure for... I bet by the time you put a long 2wd tranny in that the front drive shaft will be coming pretty close to the tranny pan at full suspension travel?

I'm going to be doing more measuring this weekend and might mock up a cardboard tranny to see what's going on. IF I can break away from the family long enough. Kinda busy time of year to be playing but this topic has me destined for a sure answer. Curiosity is doing a number on me!

[averagef250]

A C6 has a 35 some odd spline output while a 435 has a very coarse 10 or so spline output.

[fomoco390]

My '76 Highboy has a 460 and C6 from a '73 Lincoln - long tail. It's got a custom (short) driveshaft, and I've been running it for years. I have had to replace u-joints once. The real problem, as mentioned, has been the transfer case shifter. I attached it to the floor pan in a way, but it's still not stable. You really need to make a boss for the shifter on the tailshaft before installation - it would make things so much easier.