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rich6700

Front pinion angle ?

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Here's the problem. Last month I rebuild both rears and replaced the rear drive shaft. After the rebuild both rears were quiet running on the jack stands. I could feel a slight vibration at highway speeds. I took it out for a road test and there was a good vibration starting at 50 mph. thinking the rear pinion angle was off I parked the jeep until I could put adjustable rear control arms on. I installed the rear arms and set the pinion angle 3/4* below the drive shaft angle. took it out for a ride and WTF it's still there. Naturally i started over thinking the problem. So after being pissed off for awhile I removed the front shaft which I had no issues with and drove it with no vibrations. Ok, I take a look at the drive shaft and the cv end socket is screwed. This is a new shaft that was only 6 months old.(JE REEL). Take the drive shaft and had it rebuilt and shortened my front lower control arms all the way in to raise the pinion angle. Still vibrates. Lift is a 2.5 RK lift. I'm going to run out to Q-tec tomorrow and pic up a set of front upper arms. My question is what kind of front pinion angle are you guys running without having caster issues.I'm just looking for a good starting point. Thanks Rich

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What's a CV end socket?  You mean the H-Yoke or Socket End Yoke?  If there was play in the CV that could definitely cause vibration.  Normally they will start squeaking like an angry bird before they get loose.

 

My front drive shaft vibe was caused by a loose u-joint.  It was supposed to be a cross match to a Spicer 5-1310-X1 (greasable) but was too narrow.  I don't recall that it came with different width snap rings to adjust the fit, like the 1310 solids do.  Putting a genuine Spicer 1310 solved the vibe, but then the double-cardan started squealing a month or so later.  Now I've got zero vibration.

 

My pinion angle is rather steep.  I think around 5* or so.  IIRC, you want to be in the range of 1 to 3* relative to the driveshaft.  Higher angles cause eccentric movement (wobble) as the driveshaft rotates that causes the vibration. 

 

This is where Repezza joints have an advantage over u-joints: they don't bind or cause eccentric driveshaft movement at higher angles.  Unfortunately, rebuilding a Repezza joint is a much more involved and messy procedure than replacing a u-joint, and about 10X more expensive ($150 for a rebuild kit for my daughter's WJ front drive shaft).  The problem with the Repezza joint is the wear on the boot caused by high angles.  Once the boot tears grease is flung out and debris gets in, causing rapid wear.  Replacing the boot means removal of the Repezza joint, which is destructive. 

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The cardan end.

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Pissing off my wife since 87.

What brand drive shaft? I know that adam drive shaft will rebalance and rebuild but drive shaft for the cost of parts and shipping

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Je reel had it rebuilt Saturday at a place in Pennsauken. Waiting on upper adjustable control arms.

Sent from my iPhone using Tapatalk .

Pissing off my wife since 87.

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