Have some VIBES...ideas?

[steelman]

Hey all,

A while ago I put on some 2" procomp springs. I've noticed that I have some vibes between 0 - 10 mph. I lowered the stock transfer case with 4 washers, and they are still there. I installed a 1" TC drop kit, and they are still there. Any thought or suggestions to make these vibes history are appreciated. Let me know if you need any more info. Thanks!

[goodtimes]

What angle is the front (t'case end of the rear driveshaft) u-joint operating at?

What angle is the rear (axle end) u-joint operating at?

If you are still running the stock driveshaft, these angles should be equal....OEM's generally say these angles should be less than 7 degrees, Tom Woods believes you can get away with up to about 15 degrees. Personally, I doubt you will be OK at 15 degrees with a rear driveshaft in a jeep...but that is just my opinion.

I would start with finding the operating angles of the u-joints.....

[steelman]

I don't have an angle finder...have to see if I can locate someone that does.

Meanwhile, Here's the latest...My Jeep has 2" ProComp springs and a 1" TC drop kit. Last night I put on a 1" BL and 1" MML (Thanks for your help Supe! :thumbs_up) and now the vibes are definately shaking my teeth so to speak, where as before they were fairly minimal. Should I try losing the 1" TC drop since I now have the 1" MML...do you think that will help?

[nagal]

If the vibes are shaking your teeth you need to stop driving your Jeep. The last thing you want is a u-joint failure on the highway. A flailing driveshaft can do some impressive damage.

Angle Finders can be bought at HomeDepot or any other similiar hardware store for around $10.

For the time being, disconnect your front driveshaft. You dont need it to drive and no sense in putting undue wear on it because of bad angles.

If removing the tc drop helps with the ds angles, do it. The only way you will find out is by removing it and measuring the angles.

[steelman]

I removed the TC drop kit tonight, and it is better, but there are still some vibes there. Should have an angle finder in hand tomorrow and will post my findings. Been thinking...could some of the vibes be due to the fact that the new motor mounts (Currie) are poly instead of rubber, thus not absorbing much of the shake of the engine?

[goodtimes]

Not likely. Check the angles on the driveshaft and u-joints.....You can also pull the rear driveshaft out, take it for a spin in front wheel drive, and see what changes. This will tell you if the rear driveshaft is a source of vibrations or not....

[blackZZR]

hope he does not have a Slip Joint if he pulls that rear shaft

[TJSUPE]

hope he does not have a Slip Joint if he pulls that rear shaft

You wont be able to pull out the rear shaft and to think about it, even if you find out that you pinion angles are off, you wont be able to adjust them because you dont have adjustable control arms. Maybe the trick will be playing with the number of washers used.. (should I upgrade my control arms now )

When I had my 3" springs with those same exact tires and the drop, I had no vibes. I would be curious to see what would happen if you swapped your 2" springs for some 3" springs and left the drop in.

Also, a little black birdie told me this morning that this person that is letting you borrow the angle finder and pully forgot them at his place. So he may have to drop them off later tonight or he may leave them on his porch for you.

[steelman]

You wont be able to pull out the rear shaft and to think about it, even if you find out that you pinion angles are off, you wont be able to adjust them because you dont have adjustable control arms. Maybe the trick will be playing with the number of washers used.. (should I upgrade my control arms now )

When I had my 3" springs with those same exact tires and the drop, I had no vibes. I would be curious to see what would happen if you swapped your 2" springs for some 3" springs and left the drop in.

Also, a little black birdie told me this morning that this person that is leetin gyou borrow the angle finder and pully forgot them at his place. So he may have to drop them off later tonight or he may leave them on his porch for you.

OK...leaving them on the porch would be cool...just leave them next to the adjustable control arms and 3' springs that you'll be leaving as well!

[goodtimes]

step one: get rid of slip yolk. I forgot people still use those things.....

[TJSUPE]

step one: get rid of slip yolk. I forgot people still use those things.....

well, its not by choice and it aint a cheap mod. SYE + Driveshaft. Then if you getting all that you obviously going to need adjustable control arms....

Domino.....

[blackZZR]

sears sells a protractor for around 10 bucks

you put it on the flat of your drive shaft
then on the bolts on the diff cover
dependeing on the modle you may have to subtract 90 drgrees fron the measurement of the diff cover
then adjust however you can adjust

If you own a jeep, a 10 buck investment is kinda cheap, seems everytime you mess with a mod you need to adjust that angle

[steelman]

OK...I haven't had time to go get an angle finder (will get one early next week as I'm heading out of town for the weekend tomorrow afternoon). Wanted to throw another fact into the ring here to see if help in the meantime. My rig is an automatic, and when I'm in drive but have the brakes on (like at a stop light) is when it vibrates the most. Could this have anything to do with the new MML being a poly one instead of rubber like the stock one? Is still vibes upon accelleration as well, but it's definately worse at a stand still. Then again, if I'm at the stop light and kick it up into Neutral, the vibe are almost nonexistant. If it were the angle of the driveshafts or the u-joints, would it vibrate as bad as it does in drive with the brake on? :dunno:

Sorry for the running statements above...lost control of my mind and fingers!

[blackZZR]

drive shaft would not be turning at a stop with the brakes on, it is in the engine, check for a misfireing cylinder

[mrblaine]

OK...I haven't had time to go get an angle finder (will get one early next week as I'm heading out of town for the weekend tomorrow afternoon). Wanted to throw another fact into the ring here to see if help in the meantime. My rig is an automatic, and when I'm in drive but have the brakes on (like at a stop light) is when it vibrates the most. Could this have anything to do with the new MML being a poly one instead of rubber like the stock one? Is still vibes upon accelleration as well, but it's definately worse at a stand still. Then again, if I'm at the stop light and kick it up into Neutral, the vibe are almost nonexistant. If it were the angle of the driveshafts or the u-joints, would it vibrate as bad as it does in drive with the brake on? :dunno:

Sorry for the running statements above...lost control of my mind and fingers!

You live less than 10 minutes away, you could always swing by and I"ll give you an opinion, it may not be right, but I'm not always wrong. Or, I've got to test drive a rig here this evening, I could swing by.