Topic: Dual Case Drive shaft length with CV??

[spc mike]

Ok so i am preparing to to shorten my drive shaft because of my dual case setup I'm gonna be putting in. My question is whats an accurate way of determining the amount to cut out of the drive shaft? Should i take out the exact length of the adapter and crawl box? Also going to be putting in a CV to help with the angle. Its a single cab '85 with plans to lift it about 3-4 inches.....I'm sure someone on here has a similar setup, so maybe those people can help me out. As of right now i was planning on taking the length of the crawl box and adapter and then subtracting 3-4 inches from that to compensate for the lift that's gonna happen later on. have too take in account the CV too i guess.....anyways if you guys have any advice let me know.

[IronClad]

best thing to do is get it all together and then measure it.. you can speculate all you want but untill its actually put together you will never know and there is no way to tell

[4RunnerChevy]

Measure flange to flange, and figure out max compression.  If you running stock spline, you want to make sure you have enough space for compression, and the maximum amount of extension.

[Dingman.]

Yes make sure you measure from flange to flange and on the same spots on both flanges (bottom of both, etc.)

Your more than likely going to need a long slip front driveline unless your linked in the front or really have no flex at all.  You also may need to clearance the cv depending on your angles amd which cv you have.

Is this a rig that's goint to be trailered or street driven?
I ask because if you don't want vibrations I would have a shop do it.  Sure you may get lucky if you do it yourself and have it be straight and not too far out of balance but that rarely happens.

Another thing is if you plan on doing it yourself you have to phase it when you assemble it (look it up if you are not sure).  If you are reusing stock tubing it is thin an prone to ripping apart if you hit it on a rock so you may want to retube it with thicker tubing.when you layout the driveline before assembly your going to want to shoot for about 1.5 inches off bottom at ride height. And do not count on getting it straight unless you have some sort of apparatus to keep it consistant while you measure the runout.

There is a lot involved in making them vibration free.

[yoshaleng]

best thing to do is get it all together and then measure it.. you can speculate all you want but untill its actually put together you will never know and there is no way to tell

X2

[spc mike [OP]]

Thanks for all the input. I'm either gonna guess right now or wait till i get the leafs in the rear until i shorten it...just wanna get it on the road sooner than later.

[scoutrunner]

probably not too worried about the front since not driving in 4hi around town.  thats what I am thinking on mine.  Mountian cop just made a square drive shaft maybe hit him up about it. thats another route on the front. the rear I would have a shop or see what marlin charges to do a long spline shaft!  camping time is getting closer!

[spc mike [OP]]

ya, I'm worried about the rear for now....and i am definitely having a shop build it because i want it balanced and done right. The front i don't need right away but i will likely build a square shaft though.

[Dingman.]

You dont want a long spline for the rear.

You would be plenty happy with a cv, the standard slip and thicker tubing.

Get your cases installed and then measure the length and angle.  Then call a shop and order a rear shaft.  You may need to roll your pinion up towards the tcase depending on what your measurements are but the shop would be able to tell you.

Now I'm off to go build some.    

[blackdiamond]

Keep in mind that when you go from a standard universal style driveshaft to a CV style the required driveline angles are very different.  For the universal style the transfer case and differential flanges should be parallel with each other.  The goal is to have the angles at each end of the shaft equal.  With a CV style you want the differential flange to point directly at the transfer case flange so the only angle is on the CV end of the shaft.  If you don't get this right then having a balanced shaft won't matter.

[spc mike [OP]]

Thanks blackdiamond! that's some good info.

[blackdiamond]

Thanks blackdiamond! that's some good info.

You're welcome.  Make sure you do more research on this topic and don't just take my word for it on the specifics.  I had my rear differential rotated when I went to a CV style rear driveshaft.  One the front the angles are not nearly as critical unless you plan to roll in 4 Hi on the road.