SOA LIFT NOW BAD VIBRATION

R

RedWrang

New member
1055215

Ok my soa is complete, but im getting some kind of vibration only when I take off from a dead stop. Once I get rollin it smoothes out just fine. The rear shaft is not in a bind or anything and its driving me crazy. My rear shaft is plenty long enough. And the angle is perfect. Any suggestions let me know.[addsig]
 

1055228

I did the SOA in my Jeep and I have the same vibration you are describing. I haven't tracked it down yet since it is not a real big deal to me at this point. I am going to try and put on some traction bars to see if that helps. I am thinking the vibration may be a slight amount of axle wrap in the beginning of take-off-

I will let you know if this helps anything-[addsig]
 

1055254

I am not really sure but I think it is when torque is applyed to the differential it transmitts to the axels. This causes the axel housings and hoghead to want to rotate either up or down depending on the forwards or reverse direction of the wheels. causeing it to try and move in the u bolts. This is the reason for traction bars to keep the wrap or movement of the rear end from changeing angle. Let me know if I have this figured out guys. tug I do miss the meaning so many times![addsig]
 
1055304

Thats exctially what ive got is axel wap. Its that my rear pinion is not right i got it too straight with the rearend. Ill fix it this week. A few pics are up at photos.yahoo.com/baddjeep2002[addsig]
 

1055368

I know what your problem is. I can tell by the pictures. Your pumpkin is at way to high of an angle for the amount of lift you have. While you take off your getting spring wrap and that is even making it more of an angle therfor givin you the vibration. Get some 2 degree shims or something and aim your rearend down a little.

The face the the pinion yolk (Rear end) needs parralell with the face of the Transfercase yolk and then up just a little.

edited by: Jeepin91, Feb 16, 2003 - 11:44 PM[addsig]
 
1055374

i agree with jeepin91... that yoke looks like its shootin too far up. the correct angle would be determined by measuring the angle of the Tcase's output shaft in respect to a flat ground, subtract 2 to 3 degrees and using that angle as the pinion angle in respect to the ground... the subtraction of the few degrees allows for the pinion to move upward when torque is applied to the axle and move into the parallel range. otherwise... the jeep looks good, and will look even bad-ass-er with some mud meats on there. i wish i had the money to do it

edited by: Snitty, Feb 17, 2003 - 10:03 AM[addsig]
 
1055379

Jeepin your right I dont know what happened, I could have swore i had it set right when I welded it but what the hell its a Jeep thing. Ill just redo it no problem. Snitty I did not spend but 57.00 for the pitman arm and about 40.00 on the rest of the stuff to lift it. So go get the stuff and get yours done. And for the record BIGGER BADD ASS tires are next on the agenda. Its just telling my wife I need more money for the Jeep. She dont understand Just Empty Every pocket.[addsig]
 

1055407

I would just put a shim in each side and bring the angle down. No reason to cut them off and do it again. Shims are only like $15.00. Then if you ever go bigger on lift, then you dont have to change anything but maybe smaller shims or just take them out to get your angle right.[addsig]
 
1055408

Put some new u-joints in the rear driveline while you have it out of there also. Those really contribute to some vibrations. And KEEP A SPARE in your rig. When I had a stock driveline in the rear and lift and blew them all the time wheelin'

edited by: Jeepin91, Feb 20, 2003 - 03:53 PM[addsig]
 
1055565

once again... agreed... you can shim them.. and if you ever go with a cv driveshaft, it looks like you're already set as far as pinion angle... I'm aware of the easy wallet on the SOA... but i plow with my jeep and its a good source of money for now.. I don't want to halt that right yet[addsig]
 

1055579

Instead of re-doing the welds, or adding shims, remove the transfer case drop kit. That might bring the output of your t-case in correct angle with the pinion output. Just a suggestion. Otherwise, do the shims, much easier.[addsig]
 
1055587

hi-c I actually am going to lower the trans case another 1/4 of an inch. Snitty I hear what ur saying but when you get ready if you need any help let me know.[addsig]
 
Dont take out your t-case drop down kit untill you get a CV driveliine. Your stock one cant hadle that kind of an angle. The best plan it to get a CV driveshaft and a slip yolk eliminator kit. But that gets a little spendy. I have CV drivlines front and rear.[addsig]
 

1055932

Ok I went all the way to a 4 degree shim and it made a very small amount of difference. I cut the spring perches off and will weld new ones on today. [addsig]
 

1056004

The vibe is so little that my wife could not notice it. The way I knew a very little was there is cause I know what im feelin for. But for the most part its pretty good now. My friend says I need to lengthen my rear shaft but the yoke that sticks in my trans case is 3 3/8 in overall and I have 2 1/8 of that sticking in. What do yall think. He says to lengthen it 1 to 1 1/8 of an in but then it will be too long. Im going to put some leafs out of a 3/4 ton chevy in my pacs and see if that stops some of the spring wrap too. [addsig]
 
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