Driveline angles, please help me understand (1 Viewer)

[ARB777]

1997 FZJ80 with 3 inch icon lift springs, caster correction bushings, 2 inch drop brackets, 285/75 16 ko2s.
I started out with the icon 3 inch kit with the supplied caster bushings. At that point there were no noise on the driveshaft. Steering was bad though and i thought the bushings did not give me enough caster. So i ordered 2 inch MAF drop brackets and retained the caster bushings. It did correct my steering but it developed driveline noise. Pulled the front driveshaft out then the noise is gone. After reading a bunch of threads, I am convinced that i dont need a double cardan shaft. I just need to correct my angles.

So my question is, If i remove the caster bushings and replace with oem bushings and replace my 2 inch drop brackets with 3 inch drop brackets, Would it correct my driveline angles? At least theoretically? And if I am correct in assuming that, Will my stock driveshaft length be ok with the 3 inch lift? Meaning, would it cause noise due to being stretched out because of the 3 inch lift? Thanks.

 

[inkpot]

Did you try adjusting the toe in when you first had the castor correction bushings?

 

[ARB777]

Did you try adjusting the toe in when you first had the castor correction bushings?

No. I wish I asked that question before i bought the MAF brackets. However, wouldnt the caster correction bushings twist the axle where it would put the pinion at a different angle than the transfer case?

 

[baldilocks]

If you have correct castor angle with a 3 inch lift, your pinion to driveline angle is most likely near zero which means you need a DC front driveline.
Is your rig heavy in the front (big bumper, winch, dual batteries, 800 lights, high lift Jack .... Etc? If not then I would suspect that your new springs rendered a bit over three inches, especially until they settle.
Every 80 seems to have its own personality so what works for you may not work for me. The best thing you can do to help us help you is to put your front shaft on and post a couple good photos of what you have going on.

 

[inkpot]

Op said the DS was ok but not the steering with the first setup. Toe in changes with lift, and second guess would be bushings. Take a good flashlite and look over all radius, control arm, and panhard bushings for cracks and splits.

 

[ARB777]

If you have correct castor angle with a 3 inch lift, your pinion to driveline angle is most likely near zero which means you need a DC front driveline.
Is your rig heavy in the front (big bumper, winch, dual batteries, 800 lights, high lift Jack .... Etc? If not then I would suspect that your new springs rendered a bit over three inches, especially until they settle.
Every 80 seems to have its own personality so what works for you may not work for me. The best thing you can do to help us help you is to put your front shaft on and post a couple good photos of what you have going on.

Hi baldilocks! I think you suggested on my previous thread to get custom dc ds. On my previous thread i was trying to source a taco driveshaft but it is so hard to find. I considered a tatton driveshaft but it required the spicer flanges to be machined so that the bolts would engage fully. Almost went for the tatton one but my dad advised against it. He said grinding off part of the flange would compromise the structural integrity of the bolt holes and might eventually fail. So after reading and reading bunch of threads, drew me to a conclusion that I can correct the angles to stock geometry with the correct drop brackets which is 3 inches vs what i have right now(2 inch) and replace the caster bushings back to oem. Am I making sense?

 

[ARB777]

Op said the DS was ok but not the steering with the first setup. Toe in changes with lift, and second guess would be bushings. Take a good flashlite and look over all radius, control arm, and panhard bushings for cracks and splits.

I see your point inkpot. I have new panhard bushings, TRE's and the poly caster bushings. Only old bushing is the rear most front control arm bushing. How much toe in would you recommend? However, after the MAF brackets, steering was almost back to stock.

 

[ARB777]

If you have correct castor angle with a 3 inch lift, your pinion to driveline angle is most likely near zero which means you need a DC front driveline.
Is your rig heavy in the front (big bumper, winch, dual batteries, 800 lights, high lift Jack .... Etc? If not then I would suspect that your new springs rendered a bit over three inches, especially until they settle.
Every 80 seems to have its own personality so what works for you may not work for me. The best thing you can do to help us help you is to put your front shaft on and post a couple good photos of what you have going on.

Forgot to answer your question. I am all stock except for springs shocks and tires. No additional weight to pull it down. So it yielded more than 3 inches.

 

[baldilocks]

Hi baldilocks! I think you suggested on my previous thread to get custom dc ds. On my previous thread i was trying to source a taco driveshaft but it is so hard to find. I considered a tatton driveshaft but it required the spicer flanges to be machined so that the bolts would engage fully. Almost went for the tatton one but my dad advised against it. He said grinding off part of the flange would compromise the structural integrity of the bolt holes and might eventually fail. So after reading and reading bunch of threads, drew me to a conclusion that I can correct the angles to stock geometry with the correct drop brackets which is 3 inches vs what i have right now(2 inch) and replace the caster bushings back to oem. Am I making sense?

Your castor may be exactly as it was prior to the lift but now your transfer case output is 3+" higher. This increases the overall operating angle and decreases the pinion angle to near zero on these trucks. Did you provide photos in your previous thread?
My DC shaft was built using NeapCo DC yokes and spicer UJoints. These parts were made for thes applications because OEM parts are becoming difficult to find so the bolt pattern was perfect. I had my flange thickness machined down to the same thicknes as the Toyota flange it replaced. How can this be a problem?

 

[inkpot]

Most rigs do well with toe in set at stock numbers. Have seen a few really tall rigs that seemed to handle best with about 1/2 degree more toe in than stock.