texcat101

Well I fixed a couple of problems and created or worsened another. I added 1 1/2" longer shackles to the rear and used 1/2" thick offset plates to move the axle forward 3/4". the rough country springs had shims that I removed to better accomodate the offset plate.
I took it to a nearby trail and wow what a difference on the suspension travel , it just floats over the trails, really awesome what these rigs can do!
However, I already had some minor noise in the driveline when letting off the throttle ( coast noise ) at highway speeds. after todays mods it is much worse! The rear lift should be right at 4", I am posting pics of the driveline angles, they don't look that bad to me but I don't have much experience with lifted vehicles.
About how much lift does it take before you need double cardon joints?
Anyone else have similar experience? Thanks for your help.


This is what it looks like w/new shackles.

JsEngine&repair

If its a growl type noise with a bad vibration, id check the wheel bearings. Look at my thread and if the noise sounds like the one you have, then you know what it is.

Hayes

sounds like the DS bearings... That's what mine was doing (only on coast) and when I replaced them, all gone!

texcat101

Just had them reworked at a driveline shop- spun and straightened.

I just found a thread from 4crawler on driveline101 that indicates the rear pinion flange angle should be same relative to level or 1-2 degrees lower than the trans flange. This seems contrary to logic- but it's not. He explained it and clearly my pinion angle must be shimmed down before I will know what I really have going on.

texcat101

well I have a better handle on the driveline problem. this could be helpful for many people. Based on the info from 4crawler
http://www.4crawler.com/4x4/CheapTri...FixingProblems

I checked the angle of the trans flange and the pinion flange there was an 8 degree difference in the flange angles, the pinion flange is recommended to be 1.5 degrees lower than the trans flange meaning I needed to move the pinion down 9.5 degrees.
I had some shims laying around that equaled 7/16" of taper so I installed them and it changed the angle by 5.5 degrees so I ran it down the road and it made little to no difference.
realizing that if I put the frame on stands and unshackled the rear of my springs I could put my floor jack under the diff housing and lift it to decrease the pinion angle while my wife was in the 4runner accelerating and decellerating the driveline. As a safety measure I put another set of stands under the axle housing to insure that the tires could not touch the shop floor.
well just as 4crawler said when the pinion angle got to 1.5 degrees less than the trans angle the driveline noise went away. Amazing!
Some quick math tells me that a shim with 3/4 " taper will give me the desired angle. seems like a lot of shim so I am thinking of cutting and rewelding the spring perches.
Has anyone done this much shim before?

4Crawler

iTrader: (3)

As I replied on your other post, have made shims of 12 or more degrees. Moving the perches is a good option if you can do that. Or from the looks of the shaft, have a CV joint put on the top end since you already have the bottom end of the shaft in nearly perfect alignment for a CV.

texcat101

I would much rather shim it because I leave for Colorado this week. Was I correct to understand the pinion flange is best at 1.5 degrees less angle than the trans flange due to loading movement? Or should I set it at the same angle?
Also I like the idea of running the pinion more level for lubricating the front bearing.

4Crawler

iTrader: (3)

As noted:
- http://www.4crawler.com/4x4/ForSale/Shims.shtml#FAQ1

You want the pinion angle 1-2 degrees low to allow for the pinion to tilt up under load. That is unless you are running a rigid traction bar that prevents axle wrap.