Stomis

So things are beginning to roll on getting the sas done. My third is being built, I'm ordering my rear trail-gear lift kit tonight and the hangars are getting welded in next weekend.

I'm beginning to set my mind to my driveshafts. I've read tones of stuff on slip, length, blah, blah. I cant seem to get a definate answer so i figured I'd ask here.
I'm going to get a second IFS front driveshaft out of the junkyard to have extended. For the front my question is with a 5" lift how much should I have it extended and is the long slip really required?

For the rear I'll be running 5" of lift and an adjusted pinion angles. I'll also be switching over to an older 2 piece driveshaft rather than a 3 with the center cv. How long will I need to extend my driveshaft?

4Crawler

iTrader: (3)

How long? Measure once everything is installed. Be sure to allow for compression, try stuffing the passenger side wheel to get an idea how short the shaft needs to be.

Long slip, yes, unless you plan to run tall bump stops and limit straps. Get as long a slip as you can. I run 6"-7" on my front shaft (built with the longest travel Spicer/Neapco yoke in the catalog) and it has worked fine, although I have dual cases, high pinion diff and axle forward ~2.75" which all help cut down on slip yoke length required. My spare shaft is built with something like 14" of travel, had the shop fill the upper tube with ag spline. Same spare shaft will work front or rear on my '85.

Marc P

You will need to measure your setup after it is done. Mine is 27" static. I have about 3 1/2 inches up travel and about 8 1/2 inches slip.

Stomis

Hmmm the idea is that I am trying to get some measurments off someone with the same general setup so my truck isnt down and out while driveshafts are made...

I guess the rear is the only one that matters though. What exactly do you measure? Yoke to Tcase at compression and droop?

4Crawler

iTrader: (3)

Just a case in point. Marlin (of Marlin Crawler fame) has likely done 100's of installs of dual t-cases and he never pre-makes any driveshafts. He always does the install then measures for length. If anyone would know how long to make a given shaft, he would, but he prefers to take the extra day to get the measurement first then modify the shaft to fit.

Measure flange-flange (center of both) at rest then at full droop and then get some idea of the compressed length and call the driveshaft shop. They can usually take it from there.

Stomis

Alright, what about slip? Should i let the shop take care of that too? I'm considering getting Trail-Gears Long Spline kit for the front any comments? I dont need longspline in the back do I?

4Crawler

iTrader: (3)

Measure or estimate how much you need or if your shop is up on 4x4 shafts, then see what they have to say. Otherwise, get as much slip as you can up front, the rear is fine, stock slip yoke travel is plenty. But for the front, the stock slip yoke was built for the IFS front end, diff is bolted to the frame and does not move relative to the t-case (aside from flexing of the motor/tranny mounts), so very little slip length was needed. But on the solid front axle, you have not only the travel of the springs to worry about, but with a rear-mounted spring shackle, the axle moves down and forward as it droops and up and back as it compresses making for extra slip yoke travel.

Several of the on-line vendors sell long travel slip yoke kits, AllPro and Trail Grear for sure carry them.

Stomis

On average what does it cost?

4Crawler

iTrader: (3)

Probably varies a lot with local labor rates, etc. I've had front shafts lengthened for under $100 and custom long travel shafts built out of stock front shafts for ~$300 or so.

Sonofmayhem

My square shaft has an 8inches of slip and it isnt enough with a single case and marlin 5in front springs.

Stomis

I was gonna get the trail gear slip kit. Its like 11in I beleive.

Intrepid

If you aren't changing to dual cases, just run the rear for now and leave the front off. It should be enough for you to drive around, if not flex it out. That way your truck isn't down. If you are doing dual cases, do them first, so that you can measure them and get them made while you are doing the rear lift.

In my '85 with chevy springs the stock rear works fine. I made a sq tube front, I have about 4" up and around 11" down.

drew303

*bump*

I'm finally planning my SAS and pricing everything out again. I want to do everything as right as i can the FIRST time with the money i have.

Wondering if it'd be cost effective to stick w/ a single case (I want duals) and just get my shafts modified till I can dump the extra grand+ into duals.. or is the cost of getting the driveshafts modified for a 4" spring (TG) lift not worth getting them modified twice, or replaced when I eventually do go to dual cases?