I recently acquired a '76 F250 that has been cobbled together with a little piece of everything under the sun. It began life as a hiboy, but for whatever reason it was rebuilt at some point using quite a few parts from a 78/79.

It has a 460/C6 with a married transfer case (the trans crossmember is fabbed), low pinion disc brake front end, loboy front springs, and hiboy rears. It also was a wide bolt pattern bed that doesn't fit right, but that's a whole 'nother story.

It didn't have a front driveshaft in it when i got it, so I should have known... I had a half ton front driveshaft available to me, which i thought should bolt right in. It was too long. It was an inch or so long when fully compressed with the weight of the truck on the front end.

I ended up fabricating a driveshaft from an old one I had lying around. I'm no professional dshaft fabber, but i'm not concerned, as this vehicle is for off road use only. It has single ujoints at both ends. No double cardan like the half ton had.

After installing the ******* front shaft, the angle is extreme. It is difficult to rotate. I attempted to drive the truck a short distance in 4 wheel drive, and it ripped the u bolts out. Luckily nothing was damaged otherwise, and with a new set of u bolts, I can get it back connected.

I realize that the married tcase creates a short front driveshaft that is not meant to work with a low pinion. It was suggested that I grind clearance on the yokes and that should clear up my issue, but i'm hesitant that that will clear it up completely. I'm worried that if I hit a bump or something and articulate the front axle just right, I'll break something again.

Would angle shims on the front axle help? I know it would screw up caster, but again, this will never be on the road...
Is it possible to clock the transfer case and drop down the front drive side?
I'm open to any and all suggestions.

Thanks

 

i had a buddy one time that had a dodge the he bought a transer case drop kit to help his driveshaft angle......

 

I think that you have 2 options and each one will cost some money. The easiest fix would be to put back the original Highboy style drive train. Divorced NP 205 style transfer case with a short drive shaft from transmission to the transfer case. Hopefully the original transfer case cross member is still in place. I have seen a 6-8 " lift kit installed back in the day and the drive shafts will work with the low pinion front axle and function properly. The other option is to put a 78-79 High Pinion front axle in the front end that was designed to work with the married type NP435 / 205 transfer case. I had a 78 F-250 and put the HD closed knuckle drum brake front end in place of the HP axle. It was not a lifted truck , but I was able to do a short drive shaft from the married NP 435/205 using only a single u-joint at each end. I did have to grind the pinion yoke for clearance and it worked for back woods wheeling. If you looking for major lift for the truck I would run the HP front axle with the divorced 205 and the only issue might be the rear drive shaft angle. I do not think that you will be able to get enough clearance at the transfer case and pinion with the extra lift that comes with the factory Highboy. Just my 2 cents on possible options for your off road truck. Keep on Wheelin.

Matt
73 Crew Cab (4x4 Soon )

 

I run a direct mount case in a shortbed truck with 44 inch tires. What I am getting at is that my lift required to clear 44's has got to be more than you have with stock springs and the same transfer case, and the low pinion axle.
There are some options, and one is to use a yoke for the double cardan shaft, lower the transfer case slightly by dropping the x-member, installing high angle yokes, or at least larger u-joints which will operate at a greater angle, install a high pinion front end, rotate the front pinion up, or any combo mentioned above.
Either way, you will have to cycle the suspension completely to verify travel.
Ive never been a fan of grinding on yokes to make clearance.
This compromises strength of the yoke.

 

Thanks to all for your responses.

I would definitely like to go back to the divorced transfer case setup. I have no idea why this truck got changed.

I gave $200 for this truck and I certainly got my moneys worth, but it's hard to justify the cost of locating parts to put it back.

Which crossmember is important to still be there? The trans mount or the tcase mount at the back of the cab?

And isn't it rather difficult to change out the output shaft/tailhousing on a C6? I know that a true highboy did not have a slip yoke, so it was not the same as a 2wd, but wouldn't a 2wd work? A slip yoke shouldn't hurt, it just wouldn't be utilized as such, right? I have a small block c6 from a 2wd. Is it possible to swap parts from it without having to pull the current trans?

 

You can also look at installing a CV joint on each end that would allow you to have the steeper angle and not move transfer case etc.

Or somthing like this:

Tom Wood's Custom Drive Shafts - Tom Woods Custom Drive Shafts Custom Driveshafts Specialist

BAMF CV JOINT good to 42 degrees of drop.