OP
Once I eliminate these last two possibilities, I may be calling some drive shaft makers for insight. My jeep, and jeepndog's jeep are obviously extremely sensitive to changes, so we shall see.
Re-geared, now I have a vibration above 50 mph
- Thread starter bobthetj03
- Start date
Once I eliminate these last two possibilities, I may be calling some drive shaft makers for insight. My jeep, and jeepndog's jeep are obviously extremely sensitive to changes, so we shall see.
I have the same problem.
3.5"Metalcloak lift, trackbars and control arms
Advanced Adapters SYE w/ Adams drive shaft.
35" KO2's
3.07 gear (Iknow I did all this in the wrong order)
Ran smooth as glass up to 80mph
Last week I replaced the Dana 35 rear axle ass'y with a G2 Dana 44 4.88 gear and had 4.88's installed in the front(Dana 30)
Now a pulsating vibration starts about 55 or 60 and increases in amplitude to 75mph. Very regular pulsation maybe 1-2 sec. I feel it in my butt not the steering wheel.
Have you had any sucess eliminating yours?
Not yet. I've put on new tires but that didn't help, I was going to anyway so just went ahead incase it was tire balance.
I removed the front driveshaft and it did not change the vibration.
I removed the rear driveshaft and ran it in 4-Hi and the vibration went away so I know it is in the rear somewhere from t-case to wheels.
I put the rear driveshaft back in and ran it in 4-Hi just on a whim. guess what the vibration went away. Not sure what that means but its interesting for sure. Maybe the torque from the front shaft offsets the torque from the rear when in 4'hi?
Today I'm going to start dropping the t-case down with washers to see if I can eliminate it by changing the drive shaft angle even though I do have the sye. If that eliminates the vibe I may put in a motor mount lift so I can keep the t-case back up high for clearance.
I have a suspicion that the problem is related somehow to the reduction in torque when the 42rle is in overdrive. I am going to try and adjust the pinion angle and keep O/D turned off so basically I'd be running just the 3 speed automatic for this trial. If I can adjust the vibe out like this then I'll know it is directly related to the O/D gearing and probably just live with it.
My problem is being slightly OCD. The vibe isn't bad, passenger can't feel it. I think I can bring myself to live with it if I know what the problems/cause is. Not knowing is driving me nuts.
Keep me informed and I'll post my progress on here
OP
Pretty much the same results I'm having. Pull front shaft, vibe still there. Pull rear shaft and run 4hi, vibe gone. I tried lowering the t-case 3/4" and adjusted pinion 1.5* lower, didn't help. Vibe same no matter what, and I'm a bit OCD too. My wife says she can't feel it in the passenger seat, but I definitely feel it. My setup was a bit different than yours in the fact that I had Metal Cloak double adjustables in upper rear, and Currie lower arms rear. So I tried an experiment and removed the Currie Lowers and put my stock arms back in. Vibes lessened a bit. Still there, but better. So, the JJ's were transmitting some NVH. I'm starting to wonder if the Duroflex joints are also transmitting some too. Doesn't solve the root cause of the vibe, but I'm gaining on it. I have virtually replaced/rebuilt everything in the drive train except the trany. I have the 5 speed. Next up, replacing the rear diff yoke, since it's the only thing left I haven't replace sans the rear axle shafts.
OP
If that doesn't help, then I think I'll pull the rear drive shaft and take it to a drive line shop to have it checked for balance. It's a brand new Adams shaft.
Go ahead and change the yoke, but since I had 2 bad Adams shafts, I still have every reason to believe you got a lemon from him too. Keep posting with progress.
OP
I hope you are right. The yoke change will be an upgrade cause I'll get the u-bolt style which is stronger.
OP
When I changed the front yoke to that style, I snugged them with a box wrench till I thought they were tight enough. I didn't wail on them with a breaker bar or anything, lol!
OP
Wouldn't take much to fall off the edge right now, but thanks for the tip on the u bolts.
What do you mean by a 0 degree pinion angle? As in there is no difference in angle between the pinion and driveshaft angle? That is how it should be with your Adams CV driveshaft. The pinion angle can be a tad lower than the driveshaft but it absolutely cannot be any higher than the driveshaft's angle.
I'm new to this but I believe that it is now 0 (+/- .5), no difference between driveshaft and pinion. I measured the angle of the driveshaft and the angle of the differential at the flat on the back of the differential cover. The sum of those angles is 90.5 deg. If the face of the yoke is square to the back of the cover then I believe this is correct.
I intend to drive on the street for a day or two and check again. Is this the correct procedure?
Yes, those two flat spots are perpendicular to the pinion angle. Flipping the angle finder the correct way as shown here will cause the angle finder to directly show the actual pinion angle.
So long as your angles are like shown below and the pinion is no more than .5 to 1 degree lower than the driveshaft it should be fine. Personally, I don't use an angle finder... it can be eyeballed so it's right on with just a little practice.
So long as your angles are like shown below and the pinion is no more than .5 to 1 degree lower than the driveshaft it should be fine. Personally, I don't use an angle finder... it can be eyeballed so it's right on with just a little practice.
Found an interesting thread on what seems like your same issue:
http://www.rubiconownersforum.com/f...09161-stupid-pinion-angle-setup-question.html
OP finally got the issue resolved later on in the thread...
Nice info there...I have a drone at 75, and a weird harmonic. I also know my tranny dampener its original, and had at least one broken bolt in it. Might try that before replacing all my ujoints.
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