New to forum and driveshaft angle ?

[travis_crowe]

Well I guess its time to quit lurking and do a intro. I picked up my truck a few months ago after spending a while searching the auctions and classifieds i found mine on craigslist here in Billings.

Its a 81 3/4 ton 4x4 longbed with a 350 and turbo 400 po says its got a 14bolt rear (not sure how to verify or what gears it has) B&M shift kit, Edlebrock carb and intake, HEI ignition, Hooker headers. It has 33x12x16s on it and converted to manual hubs. He was a very thorough kinda guy the truck looks great well kept for 30+ years old.

So far all I have had time to do to him (anointed as jerry jeff) is add a new steering wheel the big school bus monster wasnt cutting it, a stereo and speakers, add 12v plugs, cb radio, rework the gauge yellow lens and add a tach.

I am planning a 6 inch lift around the end of the year (rough country) and moving up to 35's my question is do i need to be concerned with driveshaft angles at 6 inches? I do see I need to add the steering arm drop and longer brake lines. any other tips or things i should watch out for?

thanks for any info and if anyone has any tips on where i can take my truck out and play here in Montana Im new to the state I just moved up from Texas.

 

[travis_crowe]

oh I forgot the best part I scored it for $1,500 bucks

 

[bucket]

Howdy!

As for your angles, you just need to put it all together and see what you get. You may or may not need a longer front shaft.

 

[revo911]

i got the 6inch rough country lift..i put bigger degree shims on the front to turn the housing up more to bring the front drive shaft spines back.. it was about a inch short . did not wanna have problems in the bush.. when the money comes up this winter i will be doing the rear shaft .. would like it longer...

drop arm and lines are a must!

 

[ChevyBoy84]

I have a 6in. Rough country on my 87 with the drop pitman arm but we got it like that for $1500.00, my front and rear driveshafts are both full sliders which I wish the rear wasn't but eventually it will be replaced

 

[OYMC]

I wouldn't be to concerned with your driveline angle with a 6" lift. If your truck was a short bed you may consider setting your drive line angle but you should be perfectly fine...

The first photo shows my 1988 K5 blazer (Short wheel base of course) with a skyjacker 8" lift.

The rest of the photos show two land cruiser drive line setups I did on Spring over axle lift applications..

When I address the driveline angle I will build my new axle spring perches, set them on the clean, and stripped of original spring perch axle, set the truck on the axle with the new suspension installed, center the axle on the leaf springs, with the driveline installed (Will likely need to be lengthened on a 6" lift or bigger suspension lift) set the pinion in as close to direct centerline with your drive line, set an angle finder on your axle third member, make a note of the angle, now roll axle pinion downward until you achieve around 6 degrees difference from your original axle reference angle.

The universal joints on your driveline cannot be in direct alignment with your pinion. Universal joints must continually rotate or they will quickly ware out.

The 6 degrees of angle change will give them enough rotation to stay lubricated and will ware evenly. Under acceleration your driveline will be in close to direct alignment as your axle wraps upward from the applied torque. Typically it will be suggested to run a CV joint on the rear driveline to reduce drive line vibration from the two varied drive line angles (Upper transfer case drive line angle will have a substantial angle when compared to lower axle pinion angle to drive line 6 degrees +/- from direct alignment). On most vehicles it is the drive line angle at the transmission when compared to the drive line ange at the axle will match...

 

[OYMC]

These photos will again help explain what angles I am referring too:
The CV diagram is accurate for most 4X4 6" plus lifted trucks with exception to the axle pinion to drive line angle. The axle pinion should be rolled downward 6-8 degrees from the shown angle.

Hope all of this helps.. Again I would not be to concerned about your truck with consideration to a 6" lift on a long wheel base application. It would be preferred to reset your axle on new perches with the proper drive line angle and upper CV joint but it's not the end of the world if you don't.... Money and time baby!

 

[OYMC]

i got the 6inch rough country lift..i put bigger degree shims on the front to turn the housing up more to bring the front drive shaft spines back.. it was about a inch short . did not wanna have problems in the bush.. when the money comes up this winter i will be doing the rear shaft .. would like it longer...

drop arm and lines are a must!

This will help address drive line angles but will cause the truck to be a bit squirrelly on the road. By rolling your front axle so that the pinion rises you reduce your caster angle. A positive caster angle will insure stability (This is the angle that attributes to the steering returning to it's straight forward position after making a turn).

If you turn your front axle you should plan to cut and turn your steering knuckles to achieve the originally Caster angle or you can run a CV joint and leave it alone. On a 6" lifted truck I would again not be to concerned with rolling your front axle to fix your front drive line angles unless you plan to use 4 high regularly on the road. 4 low in a typical off road situation you would likely not notice the embalance of your front drive line angles and the limited use will not likely ware them out during the life time you own your truck, and even if you did I would rather have control of my truck then be concerned about changing out a set of universal joints every now and then.

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[89Suburban]

Cool truck Travis, I can't wait until my firewall looks nice and uncluttered like yours.

 

[8T6K5]

....po says its got a 14bolt rear (not sure how to verify or what gears it has).

14 Bolt has 14 bolts holding the diff cover on. If a 3/4T it should be.

 

[h3adbang3r14]

i have an 81 k20 but it has a 14 bolt semi float best way to tell if semi or full is look at center of axles from wheels if its flat with rim its semi and if it sticks out 6 inches its full

 

[crazy4offroad]

Rear angles should be fine, you likely have a slip yoke in the back of a NP208, you may end up needing it lengthened. Front angle is usually a bitch but I think with the longer TH400/NP208 combo the angle should be fine. If you run into problems you can get a front driveshaft from a 2005 Dodge 2500 and have it cut to length. It has a higher running angle, 1350 u-joints throughout, and the same kind of flange that bolts to the t-case as ours has.

 

[AustinDube]

Rear angles should be fine, you likely have a slip yoke in the back of a NP208, you may end up needing it lengthened. Front angle is usually a bitch but I think with the longer TH400/NP208 combo the angle should be fine. If you run into problems you can get a front driveshaft from a 2005 Dodge 2500 and have it cut to length. It has a higher running angle, 1350 u-joints throughout, and the same kind of flange that bolts to the t-case as ours has.

Hey I have A 8 Inch lift 6" spring and 2" shackle in front and my driveshaft won't reach. Would that dodge driveshaft work for my application with one of those 1" skyjacker spacers? on my 76 k10 np205 and is it only a 2005 dodge 2500 or is it the whole generation

 

[crazy4offroad]

Hey I have A 8 Inch lift 6" spring and 2" shackle in front and my driveshaft won't reach. Would that dodge driveshaft work for my application with one of those 1" skyjacker spacers? on my 76 k10 np205 and is it only a 2005 dodge 2500 or is it the whole generation

You would have to get it cut to length by a driveline shop. There's several in that year range that will work, you can tell they're the ones because they are like $400 new. Any driveline shop worth their salt will know what you're talking about. I would measure it at full droop and again at full passenger side compress and make sure the slip will be enough unless you plan on running limiting straps. You also have to know your pinion yoke size. If you're running a 10 bolt front or a dana 44 you might have to upgrade the yoke to 1350 or run a combination u-joint to get it hooked up. You shouldn't need the 1" spacer on the t-case front output end of it since the double cardan joint is 1350 throughout.

 

[shiftpro]

Here's a link you should bookmark. I.D. rear diffs..

https://ck5.com/forums/resources/axle-identification-chart.10/