Just installed Skyjacker 4"su lift 5" shackles and 4 degree castior shims, and now the ft driveshaft angle is so extreme that it binds. Talked to the guys at iho , and they said that it should not be like that with that set up, I ordered some offset u joints but I am pretty dissapointed that I have to do that since I have no money left to throw at this thing, if anyone has any suggestions on what I can do I would appreciate it thanks
ft drive shaft binding after lift install
- Thread starter ryan78
- Start date
Chris Pucci
Active member
Which way did you install the shims?
I ran a 4" Skyjacker setup for years and only had front d-shaft bind at close to full flex.
Are your motor mounts or tranny mount worn out enough to allow the rear of the motor to 'sit' towards the rear an create an even worse angle at the front output?
I ran a 4" Skyjacker setup for years and only had front d-shaft bind at close to full flex.
Are your motor mounts or tranny mount worn out enough to allow the rear of the motor to 'sit' towards the rear an create an even worse angle at the front output?
Mark Ashford
Member
Not too much of a surprise.
Sounds to me like you either need to grind the yokes a little, look at a cut-n-turn (best solution) or look into something like Tom wood's offset u-joints (which will vibrate like heck, but solve your binding issues).
With the fat-end forward you are pushing the pinion down, making your joint angle worse, but at the same time they are countering the negative caster the extended shackles are creating, and probably adding a degree or two of positive caster which will help handling and tracking.
I think I've also noticed a difference in pinion and drive-shaft yokes which would be why some people have issues and others don't. Some yokes have more meat and offer less angularity than others. If you feel comfortable you can clearance the yokes and see if that helps, or dial back the shims.
Another thing, especially if everything is new, is to make sure the bolts aren't too tight, then drive it around a bit on various terrain to "break in" the springs a bit. They most likely will soften up a bit and settle into their "natural" arch. They might be a little stiff right now and artificially lifting the truck up higher than "normal".
Also make sure nothing sticks out to you being out of place. Like chris mentions, make sure the motor and tranny mounts are where they should be, nothings tweaked or been spaced off strangely....
Just some ideas to try and/or explore.
Sounds to me like you either need to grind the yokes a little, look at a cut-n-turn (best solution) or look into something like Tom wood's offset u-joints (which will vibrate like heck, but solve your binding issues).
With the fat-end forward you are pushing the pinion down, making your joint angle worse, but at the same time they are countering the negative caster the extended shackles are creating, and probably adding a degree or two of positive caster which will help handling and tracking.
I think I've also noticed a difference in pinion and drive-shaft yokes which would be why some people have issues and others don't. Some yokes have more meat and offer less angularity than others. If you feel comfortable you can clearance the yokes and see if that helps, or dial back the shims.
Another thing, especially if everything is new, is to make sure the bolts aren't too tight, then drive it around a bit on various terrain to "break in" the springs a bit. They most likely will soften up a bit and settle into their "natural" arch. They might be a little stiff right now and artificially lifting the truck up higher than "normal".
Also make sure nothing sticks out to you being out of place. Like chris mentions, make sure the motor and tranny mounts are where they should be, nothings tweaked or been spaced off strangely....
Just some ideas to try and/or explore.
Rock Tractor
IHPA Tech Moderator
Um, with the fat end twords the front it will turn the pinion up, which is what you want.
Ya need to take a pic so we can see what's going on. I find it odd that it's binding if you installed everything correctly.
Ya need to take a pic so we can see what's going on. I find it odd that it's binding if you installed everything correctly.
Mark Ashford
Member
If he was SOA, yes. But I'm 99% sure from his original post he's stock/SUA, which would point the pinion down and increase positive caster with the fat end forward....
And yes, I had to picture it in my head as well before my original reply :d
Rock Tractor
IHPA Tech Moderator
Doh, yup my brain was lookin at it SOA.
Yup, narrow end needs to be in the front, SUA.
Yup, narrow end needs to be in the front, SUA.