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sye, new everything, still got vibes

blondejoncherokee

blondejoncherokee

NAXJA Member
NAXJA Member
Location
sacramento
ok so i just got done doing a hackntap like that australian guy who used the RE housing and found a seal for it to match the yoke that accepts a front cv shaft. still got vibes. pretty bad. im thinking my newer but used tranny mount may be bad, and that maybe the new front shaft needs to be lengthened? i have reset the pinion angle after the sye too, its around 10*, the driveshaft is around 12*. anyway ive repalced all steering(new tre's and track and stabilizer), all control arms bushings, new tires, new rear axle(dana 44 now....) new shocks, new brake pads and rotors new hubs, the hackntap sye, newer but used tranny mount, new motor mounts, so all thats left is the t case or the rear leaf springs basically. ok so basically my questions are:
- could a bad tranny mount cause vibes?
- i need to lengthen my new rear driveshaft about 2-3 inches, could that cause vibes?
- could bad rear leaves cause vibes?
- what internal t case parts going bad but still making it driveable with vibes could cause vibes?
 
I do see where you say new DS so does that mean both front and rear are new...meaning new U Joints? U Joints are the culprit IMO for at least 75% of drive train vibes. I am sitting at 6.5" of lift right now with a 242 under it and have never had a vibe yet from the pinion angle (and my rear axle has NO shims). Believe it or not the slightest side to side motion between caps on your U joints cause vibes sometimes that it took me weeks to figure out because just by grabbing the DS and shaking it not always tells you theres trouble. Well what I am trying to say is if you have not rebuilt both DS's then you really should think about it.


hope that helps.
 
Also, pull the front shaft out and see if the vibes go away. Then pull the rear, put it in 4hi and drive around. It will let you know if the vibes are front, rear, or both. Then you can track it down a little faster from there.
 
Like was kind of said above. check to make sure your front shaft is at the right angle as well. That turned out to be my problem after doing everything you did in the rear trying to track it down. Turned out that my front shaft was not at the right angle. Take the front driveshaft off and go for a spin see if anything changes
 
I just got rid of some pretty bad low speed vibes by having my BFG MT's rotated and balanced. The inner lugs on the front were worn high low every other lug. I may be changin my NEW RC shocks for some NEW heavyer duty shocks!

Boy it rides smooth now.
 
yah, ive pulled the front shaft already. and it still vibes . i had a local shop check the new shaft and they balanced it and added one new u joint upon inspection, so it should be in good shape. it needs to be lengthened about 2 to even 3 inches though, but no splines are sticking out....
 
i pulled the t case drop and that got rid of alot of vibes. new angles: rear ds-14.5*, rear pinion 10.5*. i have some vibes above 65mph upon heavy acceleration sometimes but they are only a fraction of what they used to be. i drove around with the rear shaft off and the vibes where basically gone, but still there barely upon heavy acceleration. so im thinking that its a combo of the rear pinion angle and possibly the front shaft now since the angle on the front shaft changed. since i pulled the t case drop i havent measured the front ds angle. i also have a brand new pinion u-joint on the rear ds and had it lengthened the other day as well. im gonna maybe pull the front shaft again now with the rear kinda dialed in and the fact that i havent done it with the tcase drop pulled. also replaced the tranny mount and xmember as well. if its the front shaft angle then how do i fix that? adj uca's??? doesnt that mess with castor?
 
blondejoncherokee said:
i pulled the t case drop and that got rid of alot of vibes. new angles: rear ds-14.5*, rear pinion 10.5*.
Click to expand...
Shim. The pinion should be 0* to the driveshaft, or only 1-2* below it, max.

Adjustable control arms to change the front angle, but be careful not to frak up your alignment while doing it.

Jim www.yuccaman.com
 
How do your tires look? I have BFG Mud Terrain's and they were cupped prety bad. Caused a lot of vibration. I ended up having the tires "trued", that got rid of the vibes and it runs very quite now.
 
i have 2* shims in right now. ill swap in my 4* shims tonight, that should put me at about 12-13* with a driveshaft angle of about 14.5-15.5 so that should make it better. furthermore, my front ds angle is like 6* and the pinion angle is like 3*. even though its not having toque applied could this cause vibes or is it not reasonable for it to vibe? i dont have the cash right now for adj uca's....
i havent had the front shaft checked out, so maybe ill pull it off and have the u joints replaced and the cv joint checked out. the shop said for my rear ds the cv joint and 2 u joints are in good shape, and i had them put in a new pinion u joint. it was lengethened and balanced as well.
 
swapped in 4* shims and now the angles are 13* at pinion and 15 driveshaft. the funny thing is the vibes are about the same. im thinking im gonna pull both shafts and have them fully rebuilt, new u joints and cv's. furthermore i had the tires looked at for balance etc today. tires and rims are fine. the few things i have it narrowed down to are: possibly the new front ds angle or a front ds u joint. a rear ds u joint at the cv(pinion joint is new). maybe the rear output shaft on the t case was bent and a hackntap was a bad idea and maybe a full kit is better. havent done the ball joints up front. thats basically all thats left. im a little out of ideas.
 
It could be your H-n-T,I tried that set-up 8 years ago on a brand new 2000.It still had minor vibes so I bought the HD kit,its been perfect ever since!A "bolt on" yoke fits with an interference fit VS a .001"-.002" slop fit(slip yoke)
 
youre probably right about the hackntap. everything else seems fine...
 
friend of mine did the hack n tap and he had vibes pretty good till he did a 8.8 swap and had spent about 2 hours getting the pinion angle perfect to where he has no vibes now, after watching him do that, i spent the money on the HDSYE and havent had any problems with it yet
 
I'd say once you've ensured that the driveshafts are true and the u joints okay, check for play on the yoke fitment on the rear output shaft where you did the hack 'n tap. Also, remove both driveshafts and put the car in gear and check it spinning - often when something is out of balance you can see it with the eye. Don't discount the pinion shaft or the yoke on the diff end either. A friend of mine did the RE H'nT with a brand new driveshaft and still had vibes. Shimming didn't help, so eventually they traced the culprit to be a bent yoke on the diff, after that was replaced - no problems.
 
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