Stock driveshaft question

[4x4blaze]

What's up guys, currently lifting my '87 K5 and have a couple questions about the driveshaft length. I'm roughly lifting the rear 4" with an ORD shackle flip (+2.5"), ORD super shackles (+0.5"), and ORD zero rates (+1.0") while also moving the axle rearwards an inch.

My question is, how much of the driveshaft should be sticking inside the transfer case to be safe while the truck is on its wheels? Dont want to worry about my driveshaft popping out or not being on the splines far enough.. Catastrophic failures aren't very much fun..

Thanks!

 

[6872xtc]

I believe that you should shoot for half in/out. I would believe that more in at rest would give more support and spline engagement .

 

[4x4blaze]

I believe that you should shoot for half in/out. I would believe that more in at rest would give more support and spline engagement .

Thanks for the reply! I'm just a little afraid that I may be too far out currently.. And as you stated, the more the driveshaft is in, the stronger it is obviously going to be... hmmm...

Here's a pic of how it looks. I will have to take a couple measurements as well.

 

[6872xtc]

That looks to be a little too far out from my experience . While you need room for it to stuff in, that is probably too much .
Have you looked at Tom Woods website?
I know that they have some good tech stuff, and maybe it will help you measure for correct length. Remember that it has to be sitting with the vehicle weight on the tires to check it.

 

[imiceman44]

What's up guys, currently lifting my '87 K5 and have a couple questions about the driveshaft length. I'm roughly lifting the rear 4" with an ORD shackle flip (+2.5"), ORD super shackles (+0.5"), and ORD zero rates (+1.0") while also moving the axle rearwards an inch.

My question is, how much of the driveshaft should be sticking inside the transfer case to be safe while the truck is on its wheels? Dont want to worry about my driveshaft popping out or not being on the splines far enough.. Catastrophic failures aren't very much fun..

Thanks!

If you still have the stock shaft and you did all that you mentioned above, you need a longer shaft, my guess about 2" more.
You moved the axle back an inch so you need that, andvyou lifted 4" which pulls out about an inch.

 

[4x4blaze]

Okay, good to know. So from here to here is currently 4" with the truck holding it's own weight.

 

[4x4blaze]

And okay, so ideally I want that same gap I have drawn above to be an 1 1/2 - 2"?

 

[imiceman44]

And okay, so ideally I want that same gap I have drawn above to be an 1 1/2 - 2"?

The best way to do this to contact the driveshaft place you want to work with and ask them what measurements they need.
Tom woods needs the distance from the face of the yoke on the axle side to the tip of the output shaft on the tcase.
They also need the type of driveshaft and diameter.
I think if you find a local shop yoi just a retube, and a balance.

 

[4x4blaze]

I actually do have a local shop that does driveshafts that buddies of mine have had good luck with! I would love to get a Tom Woods CV shaft, but for now, I'm just going to get this shaft lengthened.. And according to our observations and your knowledge, we know that the offset zero rates obviously add on inch, and that the lift adds roughly another inch... So. I think I'm going to go with that and have 2" added

 

[imiceman44]

I actually do have a local shop that does driveshafts that buddies of mine have had good luck with! I would love to get a Tom Woods CV shaft, but for now, I'm just going to get this shaft lengthened.. And according to our observations and your knowledge, we know that the offset zero rates obviously add on inch, and that the lift adds roughly another inch... So. I think I'm going to go with that and have 2" added

This is a close enough guess but ask the shop to confirm

 

[4x4blaze]

Sounds like a plan! Going to stop by tomorrow after work and talk with them.. Thanks for the help!