PINION ANGLE!!!!!!!!!!!!!!!!

[formula87]

Have been chasing a driveline vib for awhile now. I think I may need an adjustable trq arm because pinion angle may be off. looks like it is 2deg+ when it should be 2deg- but I get two diff readings from the rear itself and the trq arm where it bolts to the rear. here are some pics. any thoughts??????

 

from the rear end housing

 

from the trq arm

 

pic of what my be the problem the xmem.

[formula87]

more pics

 

 

off where thr trq arm mounts

 

where I measured on the rear end housing

[roadracerwhite]

I just figure out mine. The new rear rotors from the parts store weren't machined enough to let the outisde of the axle seat flush on the rotor face, causing the wheel to not bolt on straight causing one hell of a wobble.

[Frank Corkran]

Neither the TA nor the axle casting are good surfaces to use. On a Ford I use the axle pinion flange and end of the TKO tailhousing - both machined surfaces 90* from the respective shafts that you want to measure. Some have used the flat bottom of an aftermarket oil pan for the trans angle. Not sure what's a good surface you can get at on a GM axle. With a TA you shouldn't be getting the angle change on acceleration like you would with a bushed 4-link type suspension (the long TA controls pinion angle/axle windup), so shoot for 0 +/-1* difference. To go more negative on pinion angle you can start by raising the back of the tranny with spacers under the mount.

[formula87]

Neither the TA nor the axle casting are good surfaces to use. On a Ford I use the axle pinion flange and end of the TKO tailhousing - both machined surfaces 90* from the respective shafts that you want to measure. Some have used the flat bottom of an aftermarket oil pan for the trans angle. Not sure what's a good surface you can get at on a GM axle. With a TA you shouldn't be getting the angle change on acceleration like you would with a bushed 4-link type suspension (the long TA controls pinion angle/axle windup), so shoot for 0 +/-1* difference. To go more negative on pinion angle you can start by raising the back of the tranny with spacers under the mount.

 

Yea, I couldn't tell what was a good sufrace to measure from, I was planning in shimming up the trans mount or getting an adjst TA.

[formula87]

Installed the new trq arm and xmem. The xmem I fabb'd had the tranny sitting lower the new one raised it up. Installed the adj trq arm as well but still getting vib, I did adjust it per directions with angle finder see pics.http://www.ls1tech.com/forums/suspension-brakes/1112766-will-adjustable-tq-arm-help-vib.html#post12093373