Driveshaft Advice?

[the_engineers]

Wasn't sure where this should go. Please move if there is a better spot.

Looking for a little advice on my van project. The 2WD Allison has a bolted yoke. My center-to-center measurement is 70.88. I've talked to several places and have a couple options...neither of which are perfect.

Option 1: Have a slip-stub driveshaft built. The places who said they can do it are all spec'ing 4 x 0.063 DOM. Max speed would be 90 (seems ok). They still worry about the length, which makes me worry about longevity.

Option 2: Add a carrier bearing. The van has a frame crossmember 22" behind the trans yoke that could serve as a mounting location. My concern is that I don't read great things about carrier bearings either.

Thoughts? Options I haven't considered?

Thanks in advance!

 

[WVRigrat05]

Id do a carrier, They go out more often as far as vibrating on take off and such but that seems like a long driveshaft for towing etc.

 

[jlawles2]

Go for the carrier bearing. It adds one u-joint, but it keeps the rear of the allison happy. i don't think the trans would like the slip yolk putting extra axial force or vibration into the rear clutches.

Mike might have a better answer about the rear of the allison taking those forces.

 

[THEFERMANATOR]

Don't know all the details, but according to the spicer driveshaft calculator, the max reccomended driveshaft rpm for a 4" x .083(they don't list .063 in 4") with 1410 joints in a slip stub configuration is 2963 RPM's. Figuring for 3.73 gears and 245/75/16 tires puts you at a MAX reccomended speed of only 72 MPH. Sounds to me like they figured for a conventional slip yoke and not a slip stub as the extra weight of the slip stub reduces max rpm's. Based on this info, theres no way I would even consider running a 1 piece shaft.