Pinion angle... what's the secret?

Mar 08, 2005 18 Replies

I thought I had my pinion angle adjusted pretty well Sunday when I attached the driveshaft, but I have a vibration that starts at about 40mph, dies off at around 50 and picks up again at about 60.



My helper and I held a carpenters square (the big L shaped one) on the diff and lined it up that way, pointing directly at the output of the transfercase... Can anyone give tips that will get me dead on? n.


bad! the output shaft of the transfer case and the output from the rear differential should be parallel within 5 degrees or you will get a vibration. this is not true if you have a double u joint(cv joint) then what you have done applies. old john

Plenty of room for travel. CV joint, correct. n.

Sorry guys, I guess I figured folks had been following my posts closer than this... I've been posting questions about this modification for two weeks now...

Here's the specs:

2003 TJ (Rubi, if it matters) 3+" Suspension lift, 1.25" Body lift, transfer case skid probably lifts things another 1.5 - 2 inches. Adjustable rear upper control arms are pointing the pinion pretty much directly at the output of the T-case, and I do have a CV shaft on this Jeep.

The shop that made the shaft claims all their shafts are precision balanced, but I see no weights on the outside of the shaft. Another Jeeper running the same shaft also has no weights, but has no vibrations. If anyone can help me iron out these vibes, I'd appreciate it. n.

Remove your front driveshaft and go for a ride. If the vibes disappear, you have to look at your front pinion angle/castor. Do you have adjustable front control arms on this monster? I'd be willing to bet the vibes are in the front if you have done everything right in the rear.

-Brian

When we put a ford 9" in daughter's jeep and a double cardon shaft we were told from drive shaft place that pinion should be pointing 2 degrees below transfer, it's been in for a year, no vibration.

Nothing that a little JB weld couldn't fix.. :)

The Pinion Angle and the Tcase Output shaft should be parallel, not on a straight line to each other.

That's if he's running a non-cv shaft. Since he's running a CV shaft the pinion should be pointing to the transfercase.

I figured that out after I hit the Send button.

That helps. Thanks! _thumbs up_ n.

Nothing has changed in the front though... I drove into the shop, vibeless, in 4hi, with no rear driveshaft (with the t-case in it's current lifted position). The only thing I changed was the rear pinion and added the shaft. n.

What I need is an Unsend Button ...

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