Another 2 piece driveshaft angle question
 

Here are current angles on mildly static lowered 1991 suburban

tailshaft angle -2.6 slope down towards center support bearing

1 shaft angle -3.6 slope down towards center support bearing

2nd shaft -1.3 slope down towards center support bearing

pinion angle -4.8 slope down to ground

all angles as posted have a - slope. Do these fall within range, there's a very minor vibration at 45-85, brand new wheels and tires, even before with the old stock factory wheels,had same slight vibration.
Also those listed angle above are very close to the before lowering of the vehicle at factory height.,lastly vehicle has 64k original,and i've serviced since new.

Re: Another 2 piece driveshaft angle question
 

correction
all slopes are negative
2nd shaft angles towards rearend
pinion angle point's up so it's negative as well
using the spicer operating angle app
operating angle 1 is 1
operating angle 2 is 2.3
operating angle 3 is 3.5
do these angle's seem to be allright
btw- u-joints all tight,center carrier bearing no play,axle bearings,rearend,all ok.

Re: Another 2 piece driveshaft angle question
 

I've always been told that the angle should be kept within 1 degree to minimize driveline vibration. Sounds like your rear end needs to rotate up a few degrees

Re: Another 2 piece driveshaft angle question
 

Deleted.

Re: Another 2 piece driveshaft angle question
 

Deleted because you planned to say something similar or deleted because it's a complicated subject? Just want to make sure I stated it correctly.

Re: Another 2 piece driveshaft angle question
 

While the Spicer info is correct, if you ask anyone w/knowledge on the subject, as soon as the rear-end is higher than the other driveline parts the numbers yield different results.

The best results I got w/my dually was aiming the rear pinion toward the carrier bearing while not keeping it straight.

Re: Another 2 piece driveshaft angle question
 

Totally agree. 2 piece shafts are a little different than 1 piece shafts too. I think mine right now is around 5 degrees down on the tailshaft, 2 degrees down on the drive shaft, and the rear end points up around 5 degrees. It works, but I want to make it a little better. I read a ton of articles when I was setting it and probably confused myself more, but what I took from it was try to have similar angles on u joints and and have the trans and diff point opposite directions at similar angles (trans is pointing down as it points toward rear end and rear end is point up toward trans)

Re: Another 2 piece driveshaft angle question
 

So, lets make sure we're all on the same visual here....

The trans tailshaft is sloping down (higher @ the front of the vehicle vs rear (normal).

The main shaft is again higher @ the front/trans output vs the rear/carrier bearing (normal).

Is the secondary shaft higher @ the front/carrier bearing than the rear/pinion joint (normal) or higher @ the rear than the front (not normal)?

Is the pinion (@ the u-joint) pointing up toward the sky or down toward the ground?

Re: Another 2 piece driveshaft angle question
 

tailshaft down 2.6 toward ground
first shaft down 3.6 toward carrier bearing/ground
2nd shaft down 1.3 toward ground/rearend
pinion 4.8 pointed up to sky
thanks, i tried to edit very first post to make it simple but it wouldn't let me edit,i'm guessing there's a time lock after a post?