Checking for driveline vibrations

UglyDuck

TJ Enthusiast
Supporting Member
Joined
Dec 10, 2021
Messages
404
Location
Goodyear AZ
Ok so Ive completed my suspension swap and am trying to see if there are any hidden driveline vibes.
I’ve never had anything noticeable but want to make sure I’m not missing anything.
I’ve read about people feeling them through the floor, seeing their mirror get blurry, steering wheel, etc.
I have none of that. The only place I can feel anything at all (if I really search for it) is if I place my hand on my transfer case shifter.
Only thing that alerted me to check that was sometimes I hear it rattle a little (if I don’t have something like a wallet wedged in there for storage).
There’s a bit of play in the shifter as a result of being properly adjusted, so maybe that’s all it is?

CAA72897-2C2E-4C3E-B450-116827CCE300.jpeg
 
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Ok so Ive completed my suspension swap and am trying to see if there are any hidden driveline vibes.
I’ve never had anything noticeable but want to make sure I’m not missing anything.
I’ve read about people feeling them through the floor, seeing their mirror get blurry, steering wheel, etc.
I have none of that. The only place I can feel anything at all (if I really search for it) is if I place my hand on my transfer case shifter.
Only thing that alerted me to check that was sometimes I hear it rattle a little (if I don’t have something like a wallet wedged in there for storage).
There’s a bit of play in the shifter as a result of being properly adjusted, so maybe that’s all it is?

View attachment 387055
That looks very close, are my eyes deceiving me or could that pinion angle be a little too low? This is a good way to measure the pinion angle's precise angle so it can be compared to the driveshaft angle. They should be the same though the pinion angle is ok if it's perhaps a degree lower.

Pinion angle, where to measure from.JPG


PinionAngleMeasuring1.jpg


The below is the driveshaft angle.

PinionAngleMeasuring2.jpg
 
That looks very close, are my eyes deceiving me or could that pinion angle be a little too low? This is a good way to measure the pinion angle's precise angle so it can be compared to the driveshaft angle. They should be the same though the pinion angle is ok if it's perhaps a degree lower.

View attachment 387085

View attachment 387086

The below is the driveshaft angle.

View attachment 387087

Using some pretty quick measurements, without extreme precision, I measure 15° on both the driveshaft and the differential