Options for knocking front driveshaft on lifted K10?

[projo198]

I have a '76 K10 with a NP205 and Dana 60 front axle.

The truck is extremely lifted (bought it that way) and didnt have a front driveshaft when i got it.

I am trying to isolate a front knocking sound when in 4wd and am starting to believe it is the driveshaft assembly. When I first installed it I dropped/spaced the transfer case crossmember to help with thr extreme angle but believe there is metal on metal contact between my u-joints and the housing. Also there appears to be a steel ball in the middle that already has a broken seal (see photo below).

What are my options here? Do they make pinion angle shims for the front axle? Is someone making a better driveshaft to address this issue?

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[ali_c20]

You need an high angle driveshaft.
Find a good shop and have one made.

https://www.highangledriveline.com/42cv.html

https://4xshaft.com/products/chevy-...bfXeuSaMwIXB1u6W8rU2epQE5s8dV3n7b4POZGFnvOKMu

 

[nvrenuf]

The springs don’t have a terrible arch, define “extremely lifted”. If you don’t know how much lift, do this -

Measure from the bottom of the frame to the top of the front axle tube. Stock height measures 8.5”, any difference is the amount of lift. My bet based on the partial spring pic is about 8” of lift.

Yes, there is a ball in the middle of that “double cardan” or CV (constant velocity) joint. Is that assembly tight? If you hold the shaft horizontally and tilt the CV joint up, when you let go of it will it stay there or flop down? It should be tight enough to stay up.

Make sure the front driveshaft isn’t hitting the crossmember or an exhaust crossover pipe.

If none of that helps, go to the High Angle Driveline link above and read how to measure driveshaft angles and length. You’ll need that info if you have to replace the shaft with something that has a higher operating angle.

High operating angle driveshafts are expensive, expect +/- $1000.

Don’t drop the tcase crossmember, that can help the rear angle but it makes the front driveshaft operating angle worse. Put the crossmember back flush to the frame and be sure to use the factory tubing spacers on the hardware.

 

[Blazerbiker]

You don't really want to mess with shimming the pinion up, that takes caster away and makes for a wandery feeling on the road.

 

[vr1967]

I’d start with removing the dropped crossmember and go back to stock driveline angle, then go from there.

Think of it like this. If your front t case flange is true vertical (12 o’clock to 6 o’clock) with original crossmember, just adding a drop trans/t case crossmember will add to your angle, going from the above vertical to say 11 o’clock to 5 o’clock.

 

[legopnuematic]

You don't really want to mess with shimming the pinion up, that takes caster away and makes for a wandery feeling on the road.

And that is the fun holding pattern of 4wds.

Do something to improve one thing, one or two things get worse.

The front pinion angle and caster compromise, without reclocking the knuckles or the diff housing itself. Or the T case drop, helps the rear, hurts the front angles.

 

[Old Guy Bill]

If you have an angle problem and possibly too small of a U-Joint for your application.
These guys know they're stuff...

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[projo198]

Thanks for all the recommendations guys.

Before reading here I have done the following:

1. Removed the spacer under my transfer case.

2. Added 6 degree shims to the front (haven't test drove yet).

3. Removed and rebuilt the original driveshaft.

4. Added a 1 inch spacer between the transfer case and flange.

One of these things has fixed the knocking sound, but I think eventually I'll go with a new driveshaft as recommended here.

 

[DonN]

Hard the same issue when I put a NP205 in my K10 with a 2.5" lift. So, I just broke out the die grinder and clearanced the u-joint bosses until everything cleared at full droop.

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