SWB/Lift/Driveline Considerations

[MtBraun]

For context, my son and I have started rebuilding the chassis on his 84 K10. We are swapping to 14 bolt FF and Dana 44HD axles. We are debating 4" vs. 6" lift and trying to understand how much is too much for driveshaft vibration and overall stress. Powertrain will be 496 mated to a 4l80E, so we presume the weak link will be the driveshaft. I see lots of 6" lifts but not sure what they have for power, etc. Can a setup like this work at 6" of lift and be reliably drivable?

I am thinking that if we increase the pinion angle as much as possible and use a double cardan joint from the transfer case we should be ok. Thoughts?

 

[nvrenuf]

It can be done, I've run more lift and plenty of power without issues however mine was a toy so it didn't see daily service. If you think you'll go with a double cardan then look in to those used in '05 or '06 newer Super Duty front driveshafts, they are 1410 series so they're plenty strong enough.

If you step up to 1350 or 1410 joints they'll be fine, just not cheap. If you're running a lot of power I'd keep an open diff in that D44, that'll be the real problem.

 

[MtBraun]

If you're running a lot of power I'd keep an open diff in that D44, that'll be the real problem.

Can you expand on this? I just ordered a True Trac for the D44!

 

[nvrenuf]

Just small axles, if you lock it up and play in 4wd you run a greater risk of breaking axles.

 

[MtBraun]

How much is too much pinion angle? Is it possible to starve pinion bearings of oil if the angle is too steep? The spring perches on my 14 bolt are pretty roached out so thought about removing them and replacing with a new set at a custom angle for this setup. Anyone else done this?

 

[77 K20]

I'm running an Eaton Truetrac on my D44. I did put in Ten Factory chromoly axle shafts in.

I've heard it was possible to have pinion bearing issues if it was very steep- but not sure at what angle that is. Probably the guys with 14" of lift.

 

[nvrenuf]

As common as 4”-6” lifts are I wouldn’t worry about starving the pinion. Like @77 K20 said, that’s a problem related to big lifts.