Rear Axle Movement

h2oking · June 28, 2010

I installed a 9.5 AMM, 4 new autoride MR shocks, Hotchkiss rear sway bar, and Ground Force 2.5/3 spindle/spring lowering kit on a 2007 Escalade EXT. I have 24" Bazo's (35mm offset) with 305/45R24 FALKEN ZIEX S/TZ tires (34.7" diameter). I have clearanced the front and rear so that I have minimal to no rubbing statically. When one side or the other is under load and compression the rear will move forward about 1/4 to 3/8" which causes rubbing on the lower part of the front of the rear well. Statically I have about 3/8" of clearance between the tire and well. I have tested this several times on uneven hills (front up) and the rear end does go forward slightly when compressed further.

1. Is this movement normal for the four link suspension or is it a function of lowering besides the obvious closer to top?

2. Can it be corrected by using poly bushings in the trailing arms and are they available?

3. If I slot the upper and lower mounting holes on the axle about 1/4" to the front and use washers with a 1/4" spacer welded to them (filling in the area of the slot that is not used so mounting is tight and can't slip back, that way I can turn the washers 180 deg and reinstall axle in stock location) thereby moving the axle rearward, will it affect the pinion angle and handling adversely? And should I do both lower and upper or just one?

Any suggestions greatly appreciated. I do not want to lose auto leveling or change the equipment/tires/wheels installed. I also asked on the Tahoe/Yukon forum but no answer yet and this forum seems more technically orientated.