Lowered excursion pinion angle help

Arnoldb.1

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Anyone on here lowered an Excursion or Super Duty with DJM Suspension drop kit?
I have a 2000 Excursion with the DJM Suspension 3/3 drop
Kit, using the dream beams up front and the adjustable hanger and shackles in the rear. I’m having trouble with pinion angle and vibration and I can’t figure out what shim in which direction I need to use? I have all three shim degrees from DJM the 2,4,6. With the hanger setting on the highest and the shackle on the lower hole my pinion angle at the axle is 6 degrees up and the Transmission it’s pointed down 6 degrees and the driveshaft angle is 1 degree.
 

EPA

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Drop in the 4.... You want 5 degrees. Also check for tail shaft bushing play and u joints while you are there.
And just fyi perfect world the angle would be opposite of the tail shaft... Issue is on leaf springs alone the axle will twist and the pinion will twist up a bit so you leave it a degree lower to compensate for that.
 
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Arnoldb.1

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Drop in the 4.... You want 5 degrees. Also check for tail shaft bushing play and u joints while you are there.
And just fyi perfect world the angle would be opposite of the tail shaft... Issue is on leaf springs alone the axle will twist and the pinion will twist up a bit so you leave it a degree lower to compensate for that.

I tried the 4 degree wedge in the front to pitch the axle down and the vibration got worse. Driveshaft and you joints are brand new.
 

EPA

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You want it pitched up... Pinion pointing toward the trans not the ground. Pitched down is the worst thing you can do for angle. The trans is 6 degrees pointed down... The pinion need 5 up. If you draw straight lines from the pinion and follow its angle and do the same for the output shaft you dont ever want the 2 lines to cross they should run parallel to each other.And again also check for slop in the tail shaft bushing.
If its pointing downward 1 degree without shims use the 6 degree shim to point it up... That will give you the 5 up.
I should have specified the direction last night.
 
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Arnoldb.1

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You want it pitched up... Pinion pointing toward the trans not the ground. Pitched down is the worst thing you can do for angle. The trans is 6 degrees pointed down... The pinion need 5 up. If you draw straight lines from the pinion and follow its angle and do the same for the output shaft you dont ever want the 2 lines to cross they should run parallel to each other.And again also check for slop in the tail shaft bushing.
If its pointing downward 1 degree without shims use the 6 degree shim to point it up... That will give you the 5 up.
I should have specified the direction last night.

Got the 4degree wedge in tonight and it doing better and smoother at higher speed. I didn’t measure it. Driveshaft getting close to the floor and crossmember and might adjust the front leaf spring to the middle setting.
 

EPA

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Got the 4degree wedge in tonight and it doing better and smoother at higher speed. I didn’t measure it. Driveshaft getting close to the floor and crossmember and might adjust the front leaf spring to the middle setting.


It does get close but keep in mind the axle will hit the bump stops before the drive shaft hits anything.
I cut my bump stops down to less then an inch and can lower my excursion down to the point that a stock tire diameter will leave no wheel well gap still the shaft has plenty space. Thats with my axle hitting the stops so 3/4 of an inch away from the frame.
 
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EPA

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You might still need more shim if the pinion pointed down without any shims.
 

Arnoldb.1

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You might still need more shim if the pinion pointed down without any shims.

Thanks for the advice and help, It’s doing better, just a touch of vibration now. How do you post pics from an iPhone on the forum I can show what mine looks like?
 

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