Driveline and U-joints and Yokes!..Oh My!

[Scrub]

Maybe some of you that have busted up a few drivelines can give me an opinion here.

I see guys (and a few gals) building trucks up with big lifts and such and the last challenge that is tacked is the drivelines. What I want to avoid is the extrem angles I on some of these rigs.

On that criteria, I have made a decision to go with a divorced t-case. The reasons are:
1) I can center the case on the frame (allmost) and have flatter drivelines. Possibly 2 identical drivelines.
2) I can use any 2wd transmission - gear venders etc and only need to cut a driveline for an adapter.
3) It has 32 splines on all 3 yokes
4) I own it.

It turns into a balancing act. To get clearance, the t-case mount is now into the cab about 4 inches and I will have to cut a huge hole the floor under the seat and build a cover pan.

I have about 12.5 degrees of ujoint angle comming off the t-case. Does anyone have experince with that much angle. I know some rigs are well into the 20 and even 30 percent range, but I want to be able to drive this. I calculated my driveline RPM at 2650 when doing 60 MPH. According to http://www.drivetrain.com/driveline_angle_problem.html
my max at that RPM is 7 percent. I am over the published limit of 11.5

Opinons please. The drivlines look exposed to me, except that they are pretty high. The bucket is directly under the t-cace in one pic and the front line in another.

[Scrub]

Rear line

[Scrub]

Tcase

[Scrub]

Mounted

[Stocker]

I can't answer your question, sorry, but I have a question (observation?). Looking at your pics of rear diff & driveline, the diff is angled up so that the yoke is nearly straight in line with the driveshaft. This will cause the front yoke of the driveshaft to meet the t-case at a fairly severe angle. I may be mistaken as I haven't done this myself, but I thought that the angles at both ends of the driveshaft should be the same - and each u-joint will be on the same angle. That is, although front & rear yokes will be on different planes, they will be parallel to one another. I think this allows the driveshaft to spin more easily (or more smoothly) and places minimal strain on the u-joints. Hope this makes sense.

Maybe your diff is only mocked-up at this point and you're already ahead of me. Or maybe I'm all wrong! Anyway, just wanted to call it to your attention and maybe save you some grief down the road.

[Scrub]

Thanks Stocker, That's what I am looking for, Input like yours


Yeah, It's just mocked up. The drivelines are hung by string and the tcase is on wedges.

You are mostly correct, The pinion and the trans output should either be parrallel as you describe, or the pinion should point directly at the trans output and run a CV-joint at the trans output.

I am going to try the second option without the CV for starters. I have 1410 u-joints and right now the biggest CV is 1350. Tom's driveline is supposted to get the "Bigelow" joint in someday and it is 1410 in size. Pretty cool check out the site.
http://www.4xshaft.com/

I guess my real question is this, I can raise the tcase a bit more and get more clearance, but I also get greater driveline angle.

Or I can lower it and have better angle but less clearance.

I have probalby pushed a standard joint to the limit at the current locaton, maybe I should just plan on dropping 550 bucks into a driveline, but that is something I would rather avoid.

Raise it, Lower it, Leave it?

What to do?

[barraza]

Not the answer you are looking for, but it all depends. How much lift are you using? What size tires? How are you going to use it when done?
The pics dont look like a crazy amount of lift, so what you are trying to do shouldnt be too hard. However, with a divorced TC you need to worry about three shafts, all their angles and room to mount that case. If you aren't totally set on the TC you have, I would seriously look at trading the divorced TC for a transmission and TC together. That way you you will end up with the best operating angles on the longer rear shaft which will better take the everyday non-fourwheel drive miles and also be more suitable for setting up a non cv shaft. Then just use a cv shaft on the front and forget the third trans to TC shaft and finding room to fit that divorced case.

You might also be able to fab a different mounting scheme for that case that would work more like a crossmember underneath it that would solve the the body clearance issue.

As an alternative to Tom Woods shafts, contact Jesse at
http://www.highangledriveline.com/
His shafts and service get rave reviews on the CK5 and Pirate boards

[Scrub]

Good advice. I see your point, especially setting the rear driveline being near perfect for highspeed and the front for "froadin'"
The only problem with that concept is that I want to be able to drive in 4wd on the road too. We get a lot of icy days. Most likely if I need 4wd, I will be doing 45 max, but I really want both ends to work well. To do that, I need more distance from the front axle to the TC, hence the divorced case. I may need to go to a CV at the case on both ends. My goal is to get both ends near perfect. (Some people want everything )

The lift is supposed to be a 4 inch lift, but with a bare frame it is more than 6 inches right now. The tires are 20 ply industial truck tires at 34 inches tall.

I have a married 205 and 465, but the case really hung down pretty far from the frame. The divorced case is 5 inches higher. That bucket is 15 inches tall. Plus the married TC has the weenie 10 spline front output.

[Stocker]

Originally posted by Scrub
The tires are 20 ply industial truck tires at 34 inches tall.

Ummm...... you're not gonna be running those same tires, right? They should ride just about like solid rubber tires! Doubt you'd blow a sidewall in the rocks, though!

[Scrub]

Well, It's gonna be a firewood truck, and I want to be able to haul a big load. There rated at 6000 pounds each.

[Stocker]

Ah, I see. Hope I didn't come across as being critical, 'cause I didn't mean it that way. It's just that - geez, I never heard of 20 ply tires on a pickup! Well, they should do the job. Better than my 8 ply-rated, which survived an 11,300# (gross) load.

BTW what kind of wood is that huge load in your avatar? Is it a relatively light weight wood? Looks like enough to put the frame on the ground!

[Scrub]

No offense taken

That is the biggest Lodgepole pine that I ever sawed , 3 feet at the butt. Fairly heavy when wet and the old girl was gruntin' pretty hard.

The tires are rated 20 ply, but I think there are only 5 or 6 real plys. The big weight rating is at 110 PSI or something crazy. The wheels are 85 PSI max, and I run them at 50 or so. I had them on my 2wd for a while with a locker and I was amazed where they would go. Actually didn't ride too bad except they would tend to gallop at high speed. Hard to balance them.