Lifted 2WD's w/ 4" lift and a 2 piece Drive shaft - Need Help

[matad311]

So I need some help, I have been dealing with a ton of rear drive line issues. Could someone let me know what there drive line angles are for the 2 piece driveshaft? Like from the transmission to the pinion and axle housing.

Reason I ask is becasue I rebuilt my entire rear suspension, new 2,025lbs leaf packs, new hangers, and new Bilstein 5100 Shocks. Pulled a rear section driveshaft from a donor truck (Original yoke was worn out) had the driveshaft re balanced with 3 new SKF u joints and new carrier bearing. I am still using the 2" lift blocks that came in the kit originally (I made sure the tapper is positioned correctly). With the 2" blocks and new leafs its like I have 3" lift blocks in now.

So after all this I am still getting a small vibration between 25-35mph and nothing past that. I'm starting to believe my vibration is coming from the drive line angles being slightly off. And before I start raising and lowering my carrier bearing or shimming the axle housing. I want to know what others have and it you have had similar issues.

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I'm curious to see what everyone else has for angles. Because I cant go back to chunking u joints every couple months since that's what was happening from all the axle wrap I had or at least I believe that was the issue.

 

[matad311]

Well just to throw an update on this post...

I think I found the reason for the vibration, my center u joint and pinion u joint are out by 2.2degs. So this is probably the cause. I will be ordering new straight cut 2" lift blocks and see if that solves the issue.

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[Jglew82]

I bet that will help, definitely looks like your diff is angled down a bit too much. 2 degrees should take care of it.

 

[matad311]

I bet that will help, definitely looks like your diff is angled down a bit too much. 2 degrees should take care of it.

Well ill post a link but here is a video of a before and after the new leaf springs watching the pinion angle change.

So from watching my video the pinion is almost looking like its inline with the shaft. So the pinion angle needs to point down some more to to get closer to a 0 deg working angle or at least in theory and if the math is correct a 0.2deg difference.

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[Jglew82]

Well ill post a link but here is a video of a before and after the new leaf springs watching the pinion angle change.

So from watching my video the pinion is almost looking like its inline with the shaft. So the pinion angle needs to point down some more to to get closer to a 0 deg working angle or at least in theory and if the math is correct a 0.2deg difference.

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Dude, this is awesome. Great video. I think you're right on track with the angle issue.

 

[matad311]

Dude, this is awesome. Great video. I think you're right on track with the angle issue.

Thanks man, but I have 2" straight cut cast iron blocks on there way. Should be here by friday and Ill have them in sometime this weekend!

 

[matad311]

So here are my updated angles, with 2" straight cut lift blocks. I have a very small almost not noticeable vibration at 25-30mph. Would you say my drive line angles are good or do I need more improvement? Let me know!

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[matad311]

I edited the title to something more fitting....

 

[Jglew82]

Angles look about as good as you can get them. Are the shafts properly clocked together? I've seen some where they separate the 2 shafts and assemble them a spline or 2 off where the Ujoint crosses are properly clocked, which can cause vibrations. Here's a video for checking:

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[matad311]

Angles look about as good as you can get them. Are the shafts properly clocked together? I've seen some where they separate the 2 shafts and assemble them a spline or 2 off where the Ujoint crosses are properly clocked, which can cause vibrations. Here's a video for checking:

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Thats good to hear!

But yea shafts are properly clocked together, it wouldn't be possible since my center slip spline has a anti clocking spline in it. So like 2 splines are joined together witch will not allow it to be installed any other way.

Going going from that 2 deg tapper block to the straight cut block the vibration decreased significantly so I know i was moving in the right direction. But thats actually the video I watch to learn about all this lol