newbee

[low79fx]

 Was wondering does anyone know what the stock pinion angle is on an 86 GMC 1/2 ton SS ,I am going to install a 4 link.Want find out if the tranny shaft angle will need to be adjusted to match differential angle or do I just match differential to tranny angle as is ?What I am currently measuring as angle is 6 degrees which seems kind of extreme . Is anyone out there familiar with what I am trying to do? Please reply!!!Pics would also be extremely helpful,Thanks!!!

[79shortbed]

is you four link going to be adjustible(air bags,coil overs)?

how low will your truck be? if it will be about thesame as a truck 5/7 drop, find out the angle on the rear end of a truck with a drop.

what i would do is when ever you set up your ride hieght, eye ball and make it straight. Because with a good 4link your pinion wont change hardly under heavy throttle.

[79shortbed]

notice the pinion angle, its pretty straight and ride height is about 3in above that so pinion angle wont change that much.
i never had any problems with it.

this is all the way up, pinion was a little off but had no vibration, but it never rode that high

[Captkaos]

GM trucks generally run a 4 degree pitch.  6 is kinda excessive, are your drivetrain mounts good?  The pinion should be the same as the transmission only pointing up.