When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
New poster here, though I've used the forum hundreds of times in the past for super valuable info that I couldn't find elsewhere. So I can finally thank you all for contributing.
I recently posted a question in the "older, classic, and antique" thread, but didn't get any input. I figured I'd try here.
My question was about some dimensions on a Mitchell gear splitter unit. Well, I went ahead and bought the thing so my first questions were answered. It's in great shape, and for $450 I couldn't pass it up.
The wagon it's going into is a 1996 f250, 7.3, ZF, and 4x4. The extended cab and short bed mean it's about as short as they come, so my drivetrain real estate gets real limited soon after my transfer case. Adding to my fuel tank clearance issue, I'm putting a Dana 60 and SD springs under it soon too. So I'm really keeping an eye on U joint working angles. Here's a crude and unscaled diagram of what I'm trying for:
fiiinally here's my newb question:
In your experience, what's the shortest possible stub/spud shaft to run a divorced gear box? I haven't found too much technical info online, just a few pictures. The shortest shaft I could find was about 4". I've also seen a picture of someone simply running the H-yoke off of a double-cardan joint as a driveline? Although I appreciate simplicity, I'm putting some time and effort into my pickup and want reliability and years of use more than anything.
What transfer case is in your truck? My 96 has the 4406 case with the flange on the out put shaft. A 1356 will have a yoke for the u joint. If you have the yoke type, I'd try the double- cardan to join it to the t-case.
farmert, I have the flanged 4407 t-case. You don't think the flange would work with a double-cardan H yoke? I'm not doubtful, just curious
Just to make sure we're on the same page, this is an example of what I mean, from pennsylvaniaboy's post over on pirate 4x4.
Gear Vendors uses a rigid flanged coupling housing, similar to the transfer case to trans connection but it doesn’t look like your bearbox could be very easily adapted to a flanged housing. Just thinking out loud, what if you mounted the gearbox halfway between the transfer case and differential? That would give you two driveshafts to divide the angle between them.
Just thinking out loud, what if you mounted the gearbox halfway between the transfer case and differential? That would give you two driveshafts to divide the angle between them.
This is how the GV kit installs on my dually, it hangs between the frame rails. Output of the GV attaches to the front half of the rear shaft. Front half of the two piece is shortened.
I can try to figure out how to post the picture they sent.
farmert, I have the flanged 4407 t-case. You don't think the flange would work with a double-cardan H yoke? I'm not doubtful, just curious
Just to make sure we're on the same page, this is an example of what I mean, from pennsylvaniaboy's post over on pirate 4x4.
Not that the double-cardan wouldn't work, it is just that I don't recall ever seeing a double-cardan that had a flange on one end. That is not to say there isn't one out there. If you can find one I would go for it.
Gear Vendors uses a rigid flanged coupling housing, similar to the transfer case to trans connection but it doesn’t look like your bearbox could be very easily adapted to a flanged housing. Just thinking out loud, what if you mounted the gearbox halfway between the transfer case and differential? That would give you two driveshafts to divide the angle between them.
I put some thought into an adapter too, but you're right; the bearing caps on the front are a funny shape and it'd take a lot of machine hours to get something to bolt to the front of the overdrive.
Not to mention that the t-case tailhousing is cast into the rear half of the case, not lending itself to being adapted to.
And thanks Hit Man, but as for the mounting location, I need it as far forward as possible because of fuel tank and ground clearance. I had the OD sitting upside down in the first picture, so it actually hangs a good 10 or 12 inches below the mainshaft. If I split the difference in driveshaft length, I'd only have 15 or 20 inches between it and the diff, and it hangs LOW.
It's a pain, but I'll run a double-cardan on the rear shaft and clock the rear end a little if I have to. I'm tired of screaming down the highway with 4.10s and would love some longer legs.
farmert, I think I will go with the double cardan yoke, the only concern I'd have is if there was any kind of significant movement -><- or <--> between the gear boxes, since there'd be no slip joint. I'll make a beefy crossmember to hopefully control that.
Thanks a bunch for all the input, I'll get the project in gear once my Dana 60 is in, and post some pictures of the process. I'll also follow up with my tales of great success, or failure, once I finally get to test it out
-XW
P.S. If anyone's been looking for a gear-driven overdrive, there's one on the Sacramento area CL for a decent price (as of 9/30). It's a Mitchell 20K GVW unit, but it's a B model (over and under, no direct) so it's 2WD only unless you got creative with gearing. I'm not affiliated with the seller, just saw it while browsing
Thanks Bob_T, but I guess I wasn't too clear on what my idea is. But please speak up if you can see an issue with it that I don't.
From the transfer case flange, I'll reuse my flange yoke
From that, the u joint will then connect to an H yoke from a double cardan joint GUTTED of the ball stuff in the center (~$30 on the internet). So pretty much a miniature driveshaft, below
The second u joint will then connect it to the overdrive. It'll probably be a trick to change u joints, but I'm figuring that into the crossmember design
It looks like you will have the transfer case output shaft and the gearbox lined up in a straight line? I think for good u joint life we’re supposed to have a minimum angle. Not much, about half a degree. With no angle the belief seems to be that the needles are always in the same spot in the cage and will wear faster than normal.
It looks like you will have the transfer case output shaft and the gearbox lined up in a straight line? I think for good u joint life we’re supposed to have a minimum angle. Not much, about half a degree. With no angle the belief seems to be that the needles are always in the same spot in the cage and will wear faster than normal.
Good project.
Good call, I'll do some more research into that and make sure I have good geometry when I put it in. Thanks!
I don't have the sheet in front of me, but on paper, my rough estimate with the Mitchell in had my u joint working angles for the rear driveshaft at about 4.5 or 5*.
That was based on a 4" stub shaft in line with the t-case output, which Bob_T reminded me needed to be offset. Should be just a hair of drop with that short of a shaft, so I'm hoping that the 5 degree number is about right. That's about the max I'd want to run though, so any more and I'll look at going to a double cardan on the rear shaft and possibly clocking my rear end, depending on what I end up with.
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
Any Driveline Gurus?
