Hello to all, again. I’m slowly fixing the suspension woes on my new (to me) 80 series. Rear pinion angle/driveline/coil alignment is my current conundrum. With the current 6 inch lift the rear pinion angle is off of course. I have picked up adjustable upper and lower control arms but when I try to adjust pinion angle to the point the the coil buckets (upper and lower) align properly, the rear driveshaft U joint is at a disturbing angle. I would think that an angle like that would put unnatural stresses on the joint making it a natural fail/wear point. As this is my first coil sprung vehicle I acknowledge my ignorance but I’m certain that the upper and lower coil buckets need to be aligned but also know the unnatural alignment on the pinion in relation to the driveshaft/ujoint needs to be addressed. Am I over thinking it or is there a fix to this problem? Thanks again for your time and advice!
80 Series Suspension and Driveline (1 Viewer)
- Thread starter OROnorcal
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Are you planning on running 40" tires? If not a 6" lift might be overkill for what you need. It might be easier to get the right springs than all the correct links and driveshafts.
- Thread starter
- #3
I’m running 37’s.
Your output from the transfer case and input to the differential needs to be parallel within 3 degrees according to the peeps that build hot rods.
When you get the spring buckets where you want them, what is the Delta of the driveline angle?
When you get the spring buckets where you want them, what is the Delta of the driveline angle?
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- #5
I’m grinding away at work but will check in a couple days. I have the upper control arms off currently so I can go back and forth to see what works. With that said I’ve not checked the exact delta but eyeballing it there is quite of U joint angle between the driveshaft ends. Seems very unnatural but again I’m somewhat ignorant as to the strength or weakness of the joints at such an angle. Seems like it could make a u joint fail very easily.
While the working angle of the u-joint is important (the flatter the better), it's more important that the input and output be parallel and in phase. U-joints are not constant velocity joints, they have a periodic cycle and if you get the angles off, the periodic cycle will destroy them from vibration.
Your other option is to run a double cardan joint to counter the offset angle, But they are typically run in the front where changing the differential angle becomes more difficult because of steering geometry.
watch this, it explains why you're looking for // input and outputs.
Your other option is to run a double cardan joint to counter the offset angle, But they are typically run in the front where changing the differential angle becomes more difficult because of steering geometry.
watch this, it explains why you're looking for // input and outputs.
Ignore the spring buckets. Get the driveshaft angles right.
I’m going through similar adjustments on my Slinky/Icon lift, which works out to about 4” overall. When you consider that the angles will change when you get some travel off-road, do you want this to be as exact as possible, or be closer to + or - 3*? I’m perfectly parallel right now and want to set it up for the range it should be in to stay within 3* for off-road driving too.
You want it dead parallel (if possible) when parked on flat pavement.
This will minimize vibration at highway speed.
When you are off-road, especially on anything that flexes the suspension enough to matter, you should be going slow enough that the vibrations won't be noticed.
This will minimize vibration at highway speed.
When you are off-road, especially on anything that flexes the suspension enough to matter, you should be going slow enough that the vibrations won't be noticed.
Thanks Rusty, just making sure to be thorough. Kudos!
