Supercab Driveshaft questions

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Jul 8, 2008 | 09:50 PM

DeanG

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Supercab Driveshaft questions

I have a 78 F250 Supercab 4x4 with a built 460 and ZF five speed. From day one of owning this truck, the rear two piece driveshaft has been a headache. And yesterday I grenaded it completely and so now I am looking for an alternative. Has anyone on here replaced their supercab driveshaft with a custom one piece?? Any ideas on material (steel or aluminum) or diameter? Should I stay with single u joints or go to a CV in the back? Right now my Dana 60 pinion is pitched upwards a few degrees to lessen the angle, but I'm thinking with a long one piece I could have it match transfer case angle. Am I on the right track or just wishing?

Jul 9, 2008 | 10:25 AM

HI77BOY

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Just asking.

I believe that the reason they had a carrier in this truck was because the length of the driveshaft would be to long to take the torque. If you were to get someone to bulid a one piece it would have to pretty stout I would think and if you are launching your other driveline then I would consider bigger yolks and U-joints. I am putting a FI 460 and EOD tranny in a 75 HIBOY and needing much heavier driveline components.

Jul 9, 2008 | 11:11 AM

Behemoth

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From: Spokane, WA

I've been contemplating the same question, myself. The interim solution is to use my original two-piece shaft until I purchase the Gear Vendors Overdrive unit that will bolt to the output section of my transfer case. Considering the length of the GV piece, I think I'll be able to get away with a one piece shaft without worrying too much about twisting it.

Anyway, that's my potential plan of going to a one piece shaft. Probably on the more expensive side of the solution continuum, but it's what I want to do, because I'm a screwball like that.

Jul 9, 2008 | 09:47 PM

DeanG

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Can any of you racer type folk out there recomend a good source for larger U joints and yokes? I'm at work right now so I don't have the driveshaft in front of me to measure but I'm thinking the stock OEM size u joint is a 1330. Does that sound right? With a single long shaft (say 3" in diameter) what size would be safe, 1350? 1410? The 460 puts out about 445hp and 525 on the torque. The Dana 60 has 4.10 gears and I am running 35 inch mudders. This truck doesn't get used for any competition but it does have to haul my camper and ATV trailer around Montana and sometimes it can get a little gnarly.

Jul 24, 2008 | 01:18 AM

DeanG

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Ok since I got no replys to my inquiries earlier I scoured the web and checked with a local driveline service. Here is what I found out (hope some of the rest of you can use this info): It is not physically possible at this time to build a one piece drive shaft for a Supercab longbox. The yoke to yoke length on my truck measured 87 inches. A steel driveshaft of that length would flex too much in the middle and cause balance problems (and possibly grenade itself). An aluminum driveshaft could probably handle the stress but as of now there is no way to put a slip joint in an aluminum driveshaft. So the only option I am left with is to have a custom 2 piece steel shaft built using 1350 u joints (stock is 1330) and utilizing a CV joint just behind the carrier bearing. I'll let everyone know how this works out once I get it finished.

Jul 24, 2008 | 06:44 AM

Behemoth

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From: Spokane, WA

Aren't there other companies out there that will make a custom driveshaft for that application? I think Denny's Driveshaft will make pretty much anything you want, be it steel, aluminum, or even carbon fiber. I'd think they, or someone out there, could help with that particular application.

Jul 24, 2008 | 08:09 AM

Behemoth

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From: Spokane, WA

I had forgotten about another possible vendor for your situation. PST makes the carbon fiber driveshafts, and they have applications for trucks as well. On their site, they have a picture of a monster truck that's running one, so I'm sure strength won't be a problem. They ARE spendy, though. I looked for other carbon shafts, and found just a single replacement shaft for some other application, and it was over 700 bucks.

I'm not sure that Denny's Driveshaft makes the carbon fiber, but they do deal in aluminum and steel.