Ok so now I've put another 4 inches of lift in the rear of my truck and I want to correct any diff pinion angles along with a new custom driveshaft. I took two angle measurements on the diff itself and also driveshaft angle(driveshaft was just barley hanging into the slip yoke now being too short) and found that the driveshaft was running at 21.5 deg. vs the pinion was pointing upward at only 6.5 deg. Now I've done some reasearch on this and I'm thinking I have to to re weld spring perches on to correct angle. I also thought changing 4" block to a tapered block could be an option but they only change by 6 deg. Now I read an article that pinion angle should be at 2 deg. below angle running with the driveshaft due to when axle is loaded when driving the pinion will turn up that 2 deg. to make things in line. So my angle difference is 15 degrees out in total so I figure a tilt up of 13 degrees will make things inline. Now I've also heard that you don't really want to rotate axle too much due to it being difficult now to get oil to the pinion bearing. I'm about to get a custom rear driveshaft made this week with a larger diameter tube than stock also with a double u joint cv bolted to 205 t-case for extra angle help. Only thing I'm missing so far is the yolk to the t-case that will allow for a cv to be bolted up to. Any suggestions on any of this would be appreciated and where do u figure I can find or purchase that cv yolk???

 

I didn't attack my stuff the same way, but when I was doing my rear suspension, I ran with my pinion slightly down. Like you stated, it rotates up under load and runs fine.

As far as pinion oiling, I can't really speak from much experience. I am not running that much lift. Can say that being only rotated a few degrees didn't affect it (or seem to)

 

anyone else have any experience with this much lift and custom driveshafts??

 

I dont know why I did not see this earlier, but you have a veriety of varibles that are making this a little mroe difficult than it has to be.
Did you have a D shaft made yet? If no, then you are in luck. Wile you did not need a larger diameter tube, you do need a longer shaft, and longer than you think. Since you have a divorced case, and you now run a high pinion front axle, your front shaft angle is a dream. You have room to make this shaft shorter.
Here is what I mean, the driveshaft from the trans to the t-case is plenty long, and you have plenty of room to move the entire case closer to the trans. Just a few inches does wonders for rear drivehshaft angle. This will increase the front angle, but with a HP front axle, you have room to spare. You will also not have to worry about the shaft striking any crossmembers. Lowering the case also helps.
You are also about the invest into a rather expensive double cardan set-up, and this might only be available to you in either a 1310, 1330, or 1350 veriety, and this is on the small side for your tire size.
Enough of that. Your pinion angle could very well starve the pinion bearing of precious oil. Many different Pro's say many different things, but none of them suggest an overall angle of more than 20 degrees for street driven vehicles.
This is something that everyone agrees on, and that is overfilling your axle. Since you will be tilting the pinion up, you will also be locating the fill plug down, which will not permit as much fluid into the axle. This is a problem
Many have taken the stock cover (Dana) and plasma cut the rectangular portion of the cover where the plug is, and re-welding it on upside down. You will notice that the plug is located to the lower portion of the cover, and bu re-welding this rectangular section upside down, it will now be on top. This will allow you to add more fluid, and this is important.

 

not a bad idea but this means shortening my divorce shaft as well. Diff angle wil actuall bee at 19.5 degrees when all is done so sounds like it could be just within the limits at rest. I got a cv from the front end of my hpd60 but what size ujoint is in there I don't know. 1310,1330,1350 are spicer which I am soon to upgrade to on every shaft. Now some of the joints are small type with no offset(3x3) and others are 3.5 wide by 3 with a offset. I've converted most of the yolks to hold the bigger ujoints now except for the one on my tranny output. also what spicer parts #'s are these d shaft joints offset and regular?? I wanna upgrade to the 1350's all around but does that require even bigger yolks than the 3 1/2's I have now

 

Making a driveshaft shorter is easy, I mean super easy. Making them longer is the difficult part. I had a driveshaft stretcher, but loaned it out, and never got it back. (That was a joke.)
You will also have to have the front shaft shortened. Again, a piece of cake.
Series 1350 joint:
U-joint cap diameter... Dimension = 1 3/16 inches
U-joint width... Dimension = 3 5/8 inches
Series 1330 joint:
U-joint cap diameter... Dimension = 1 1/16 inches
U-joint width... Dimension = 3 5/8 inches
Series 1310 joint:
U-joint cap diameter... Dimension = 1 1/16 inches
U-joint width... Dimension = 3 7/32 inches

Maybe read this PDF.
http://www.customdriveshafts.biz/MeasuringGuide_p3.pdf

Save this. There is great info here regarding all of the yoke maunfacturers. You will be a u-joint pro in no time.

 

When I shortened my rear shaft, I used a piece of paper around it to make sure it was square. You overlap it to make the edge of the paper line up. Then I hand cut it with a hacksaw to make sure it was still square. On the cutoff piece, I carefully ground the weld until I saw a crack. Once I put the end back in the shortened tube, I clamped it on the table to phase the joints, and carefully measured around the shaft to make it square. Then I carefully welded it in a bunch of places until it was all welded up. Theres a few pics in my gallery.

 

[quote=teds74ford;6644638]When I shortened my rear shaft, I used a piece of paper around it to make sure it was square. You overlap it to make the edge of the paper line up.... A poor mans pipe wrap .lol Did this when I made my front shaft shorter just recently like 75f350 was talkin about. My only thing with the rear is I want it deadly balanced. I may just make it myself then send it down to a shop who can balance it.

 

Ok. I was just throwing it out there.

 

hey no worries whatever works

 

you can make it yourself and then have it balanced later.... Just a thought.

 

ok so I tacked my spring perches up today and it wasn't as easy as change the 13 degrees I needed . My first attempt due to the large increase of pinion being turned up it aslo made the angle of driveshaft less steep than before because pinion was higher and the angle of d-shaft was now at 18 degrees vs 21.5 when first started. So It was a fine balance of about 3 attempts to finally have it sitting at 20 degrees on d-shaft and 18 degrees on pinion angle. pain in the ***...

 

Got my new CV! I had all the parts shipped in seperately and put together with spicer sealed 1350's and made to press into a 3 1/2 tube vs. the normal 2 1/2 stocker. Usually they order them in with stock ujoints so I told the guy to build it this way. He said he's ordered many CV's for customers before but said this one is BAD ***. Driveshaft I have also has a 1350 slip yoke but just has to be shortened by about a foot. My machinist is finishing it for me first thing in the morning by cutting it in a lathe for a perfect fit. The mounting flange is pretty slick too with a machined ring that fits into CV for a perfect center fit.

 

This stuff aint cheap either... Cv and flange set me back $500 alone. Don't tell the ol' lady though