I lifted my 1991 4Runner 4 inches and the increase of driveshaft angle is creating vibrations at the transfercase. I replaced the universal joints twice and the noise is still there. It is definatly coning from that area. I tore the transfer case apart and the bearings look great but have more clearances in them fron normal milage. I'm finding no worn or damaged parts.

Two questions: Can I rotate the driveshaft around and put the slip yoke at the rear? Wonder if that would help. Is there a way of putting a Constant Velocity joint at the transfer case? (two universal joints) Wonder if that would help.

This noise is so anoying that I raped my driveshaft with 4 rolls of friction electrical tape. There has got to be a better way. HELP

 

Dude! Lemme start at the last bit - taping up your driveshaft is a bad idea, even though tape isn't heavy enough to unbalance it much.

First, when you r&r'd the shaft did you pull apart the slip joint? If so, did you make certain you put it back together the same way? When you did u-joints, did you make sure it all got hooked up again with the u-joints in phase? U-joints out of phase could be all it is.

Next, when you lifted the rear axle you might have changed the pinion angle. Poor driveline angles can cause horrible vibration. I'd check that too.

THose two things (one or both of them) are probably all that's wrong. If they are fine, then have the driveshaft checked for true and balance, and look for bent output shaft etc.

Good luck!

 

This is what I mean:

 

I out the u-joints in correctly. I watched the phase. I even took the slip yoke appart at least 12 times and turned it out of phase to see if it would get better or worse. It stayed the same. Where you got me is the angle of driveshaft. By theory the angle at the front of the driveshaft to the trans should be exactly the same angle as the driveshaft to the pinion like your diagram illistrates. But with the Trailmaster lift and having the 4 link stock system which runs coil springs there is no easy way to adjust the pinion angle like leaf suspention systems using wedges. What do you suggest? The longet I drive it the worse the noise gets. Once again I can not believe I can not find any bad or wore parts.

 

Hmm, no idea. Haven't played with coil spring Toyota rear suspensions. Just leafs and a lot of air rides that also adjusted with wedges. There are also certain angles that are not parallel that work, you may have noticed some pinions up at a real odd angle. Not the ideal theoretically, but we have a saying: "In theory, there is no difference between theory and practice; In practice, however, there is. " lol On the TJ they space the transfer case down (sometimes works, sometimes doesn't,) but I've never heard that being necessary on a toyota. You sure the control arms don't have adjustments, either on one of the arms themselves (upper or lower) or an eccentric on the arm mount bolts?

 

Here is a great article on this.

http://www.pirate4x4.com/tech/billav...ft/index2.html

I am going to put on a double cardsan CV shaft on the rear driveshaft near the transpercase. That should fix my vibration problem. Does anyone know where I can get this done or if anyone makes one for a 1991 4runner? Phone numbers?

 

Message:
let me know if you worked your noise problem out.I've got a 91 runner with a 4" lift also and it sounds like a sick chainsaw at a anything over 50 mph. Have checked everything,opened up the T case ,u joints and checked the rear backlash 3 times ! It's driving me crazy !!!!

 

There are a lot of posts on Pirate4x4.com about vibes on lifted trucks. A lot of them are happy with driveshafts custom made by http://www.highangledriveline.com.

He builds double-cardin and super angle driveshafts.

Vibration that you can feel will eventually destroy your U-joints/bearings.

 

I FIXED IT AND IT WAS EASY. The bottom line is this and this is VERRY cridical! You can not have anymore than 2 degreese drive shaft angle differance from your front universal and your rear universal. You will have a awlfull rumble and it will sound like gearing somewhere or like you said chainsaw. OK here is a VERRY EASY FIX. This should reduce your noise and maybe eliminate it all together like it did for me.
LOWER YOUR TRANSMISION CROSSMEMBER BY 3/4 INCH.
Detatch your transmision crossmember at the frame rails. Lower the crossmember and put in a stack of washers that add up to be 3/4 inch. You will need 8 stacks and longet bolts. With a 4 inch lift this will put your driveshaft angles at 1 1/2 degreese differance. You can lower it more if you like or if you are still getting the noise. I realy did not want to lower my crossmember and gile up any ground clearance but I was on the rocks today and I see no problem with dropping 3/4 inch. Good luck, it worked for me!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

Do you see this as a solution for fixing my 97 4-Runner after instaling the OME Rear Leveling Springs? Thanks!

 

alot of guys do a transfer case drop, I dont know if there is a kit for toyota, it aleviates the pinion angle and front shaft angle a bit. The best thing to do is to find out which of your driveshafts is causing a problem. Get an angle finder from lowes or home depot and check your angles too. Take out the rear shaft and drive a little bit with out it see if the front is your problem if not you know its the rear pinion angle. With leaf springs its easy to change the angle a few degrees..a 4 in lift would probaly need a 2-4 degree shim. People with rear coils are another story, not my speciality.