Driveline Vibes

[Papa Geno]

Alright guys, heres the fast rundown.

97 XJ, 231 with HD SYE, AW4, RE 4.5" lift kit with 4.5" packs instead of the 3.5" packs and shackles, 4.56 Gears on the D30 and Chry 8.25 29 Spline, with 35" KM2s.

I installed this all WITH an SYE, and put my front shaft in the rear. I got BAD vibes on acceleration and the pinion was pretty much in line with the drive shaft. So today I got 2 degree shims and shimmed the rear pinion down 2 degrees, now I dont have as MANY vibes but they are still kinda there.

So I take it for the first highway ride, and over 60 I have a PULSING Vibration that is pretty strong, and it does it holding speed, and also when im decelerating until about 50 then on decel it doesent really vibrate.

Tomorrow morning im going to throw a different shaft in the rear, and completely remove the front, and see what happens.

Do you think I need to shim the rear down more? I have no f'ing clue whats going on, all I know is im getting REALLY mad and about to just give up on this entire thing.

[Riot]

i mean listen i know im not helping you with your jeep but there is always room for grammatical improvement, and you only need to use "an" if the next word begins with a vowel.


Love you friend,
Chris, The Grammar Guy.

[Dr. Thunder]

If something like vibes gets you to want to give up on the entire thing just like that get out of jeeping now. That said do the switching of the drive shafts first and then get back to us.

[XJLI]

what condition were the shafts? u-joints have a certain memory to them, so if you change the angles and they have a bunch of miles on em theyre not gonna like it much.

Nov 4, 2008 10:10:15 GMT -5 Dr. Thunder said:

If something like vibes gets you to want to give up on the entire thing just like that get out of jeeping now.

lol x2 i missed that line first time around. i have vibes now, and guess what? i just drive through them.

[KtmRacer419]

Nov 4, 2008 10:10:52 GMT -5 XJLI said:

what condition were the shafts? u-joints have a certain memory to them, so if you change the angles and they have a bunch of miles on em theyre not gonna like it much.

.

they aren't gonna vibrate like a bitch though. in fact i wouldn't expect them to vibrate noticably anyway.

i run old-ass front xj shafts with 20 year old u joints and im sure im running them at different angles than stock.

then again, my oval tires probably hide all the problems in my jeep anyway.

[Papa Geno]

I put the shaft that was in the front, into the back, and left the front out.

Vibes got a little better, they arent so pronounced but they are still there on acceleration.

On highway over 60 they are there regardless of accel or decel..

Any ideas?

[Dr. Thunder]

Well it's not the shaft then. Same axles you ran before without any vibes? Did you get the gears all done with the lift and tires all at the same time? I'd check gears/bearings next if so.

[Papa Geno]

YEah I had the gears done while I was installing the lift.

Do you think I need to shim down the rear pinion again?

[Dr. Thunder]

Pictures. With a double cardan blah blah shaft you should have the pinion point directly to the t-case.

[Papa Geno]

I Just dont get it, like I thjought that Accel vibes the pinion is too high, and then decel its too low.

So it was really bad so I shimmed it down 2 degrees.

With an SYE the pinion is not supposed to point up at the t-case, you dont want the pinion in line with the drive shaft when its parked, you want it so when you are driving and it torques up THEN its inline with the drive shaft.

Im just fucking confused. Greg from banditt offroad is telling me to get a new shaft, but I dont have 400 bucks to drop on a fucking shaft right now.

[Papa Geno]

Here is how the rear diff is sitting right now, this is after the 2 degree shims to shim it down.

[Papa Geno]

I got an angle finder today.

Man im a fucking idiot.

I WAS AT 5 DEGREES

So I shimmed it by using a 4 degree now im sitting at 11. My friend and me are going to cut off the perches and re-weld them at 13 degrees, which is what my other jeep was set to and was absolutley perfect.

The thing sitting at 11 is much better but there are still some vibes, so well get it worked out.

[XJLI]

you got owned on naxja

[KtmRacer419]

BWAHAHAHAHAHAHHHHAHAHAHAHAHAHAHHAHAHA

[Papa Geno]

Yea I did, I was litereally editing that post and I got up and left and forgot about it.

LOL