Minor vibrations after SYE install, double check my angles

[qslim]

Dana 44/SYE/Tom Woods DS install complete. Put a few miles on it this morning, the vibes are much better than my previous setup but still there, albeit minor.

There’s a slight vibration in the stick shift up to 40mph, after that I can feel it in the floor. Again it’s minor - but there. Here are my angles, I’m about 2 degrees down on the pinion. At this point would I add another degree or two? First time I’ve messed with this so I don’t know what direction to go.

Dana 44 housing, angle finder is on the spreader surface:

Driveshaft:

 

[CodaMan]

From what I remember reading in the past, I think I would try a degree or so less on the down pinion angle.

 

[01TJ-Blues]

This will sound stupid, and it also makes zero sense but it has resolved a small vibe issue more than once.

Rotate the rear driveshaft 180* at the transfer case and try it again. It’s a quick change and you’ll be pissed if you spend days chasing the right angle and the 180* change solves it.

 

[qslim]

From what I remember reading in the past, I think I would try a degree or so less on the down pinion angle.

You mean lower the pinion more?

This will sound stupid, and it also makes zero sense but it has resolved a small vibe issue more than once.

Rotate the rear driveshaft 180* at the transfer case and try it again. It’s a quick change and you’ll be pissed if you spend days chasing the right angle and the 180* change solves it.

Sounds stupid enough to try, I’ll give that a shot

 

[CodaMan]

You mean lower the pinion more?

No. You said you were 2 down on the pinion, I think I would try it at 1 or even 0.

 

[LieutenantJohnson]

How about a picture of the rear diff pointing at the Tcase ?

 

[qslim]

I tried rotating the yoke, same thing. I’ll raise the pinion this evening & see how it feels.

Thinking out loud, the reason we set the pinion a degree or two lower is to allow fir the raise that happens under acceleration right? I installed control arms with JJs on both ends, so now I’m thinking the movement that would normally occur with bushings under acceleration would be much less w/ JJs?

 

[LieutenantJohnson]

Bring up the pinion. Like I said. I picture would help

 

[bobthetj03]

The jeep will generally tell you when it's happy, whether the pinion is low, high, or neutral. Adjust a degree at a time till you get it. I'm no jj expert, but it seems logical that they may have less deflection than the ordinary bushing.

 

[01TJ-Blues]

Just to make sure. You have a double carden and the ujoints are all in good shape?

 

[qslim]

Just to make sure. You have a double carden and the ujoints are all in good shape?

Yeah, brand new TW driveshaft to compliment the SYE. I just dialed the pinion up to match the shaft, I’ll take it for a spin tomorrow & see how it feels. Wish I had sprung for DA controls arms!

 

[Apparition]

Yeah, brand new TW driveshaft to compliment the SYE. I just dialed the pinion up to match the shaft, I’ll take it for a spin tomorrow & see how it feels. Wish I had sprung for DA controls arms!

Nicer but once adjusted, you’ll not touch them again

 

[mrblaine]

I tried rotating the yoke, same thing. I’ll raise the pinion this evening & see how it feels.

Thinking out loud, the reason we set the pinion a degree or two lower is to allow fir the raise that happens under acceleration right? I installed control arms with JJs on both ends, so now I’m thinking the movement that would normally occur with bushings under acceleration would be much less w/ JJs?

Load, not acceleration. As you get up to highway speeds, the wind load on the body is very high and will create a pinion rise both due to the high load and rear suspension squat. That and it don't matter what the angle finder say, it only matter what the vibes do. Raise the pinion a little bit and watch for a change to let you know you are going the right way.

 

[Rubicon88]

This will sound stupid, and it also makes zero sense but it has resolved a small vibe issue more than once.

Rotate the rear driveshaft 180* at the transfer case and try it again. It’s a quick change and you’ll be pissed if you spend days chasing the right angle and the 180* change solves it.

This...

And disturbing your u-joints if marginal to begin with a new angle can change the nvh.

Tires...

'Your vibes are better now but not gone."
Perhaps you had a couple underlying issues and possibly a trio to which one is now fixed.

P.s.
You know how people used to fix shit by turning up the radio....
Same thing applies by running the biggest lugged tire.
J/K.....


Maybe