Stanley Posted March 31, 2008 Report Share Posted March 31, 2008 Since lowering my 05 SS I get slight vibration above 75 mph. What range of angles should the front and rear axles on an AWD SS be after lowering to eliminate vibrations. I’m in the opinion that the angle of the front axle is too steep. Quote Link to comment Share on other sites More sharing options...
12'SROCK Posted March 31, 2008 Report Share Posted March 31, 2008 how low did you go and what components were used to achieve your drop? Quote Link to comment Share on other sites More sharing options...
haul@ss Posted April 2, 2008 Report Share Posted April 2, 2008 hmmm... im gonna take a wild guess... shackles and hangers! am i right? haha. i dunno exact specs but the search button is ya friend Quote Link to comment Share on other sites More sharing options...
Stanley Posted April 2, 2008 Author Report Share Posted April 2, 2008 how low did you go and what components were used to achieve your drop? I used Beltech spindles up front and spring hangers in the rear which gave me a 2 inch drop in the front and a 1 1/2 inch drop in the rear. Also, I never noticed before the drop but the front differential now is lower than the center of the front wheels. Quote Link to comment Share on other sites More sharing options...
1BAD2K Posted April 3, 2008 Report Share Posted April 3, 2008 I used Beltech spindles up front and spring hangers in the rear which gave me a 2 inch drop in the front and a 1 1/2 inch drop in the rear. Also, I never noticed before the drop but the front differential now is lower than the center of the front wheels. why did you use hangers and not shackles? Quote Link to comment Share on other sites More sharing options...
Stanley Posted April 3, 2008 Author Report Share Posted April 3, 2008 why did you use hangers and not shackles? I was under the impression that the hangers would give me a 2 inch drop, I thought that the shakles woud drop the rear too low. Quote Link to comment Share on other sites More sharing options...
NTMD8R_SS Posted April 3, 2008 Report Share Posted April 3, 2008 I was under the impression that the hangers would give me a 2 inch drop, I thought that the shakles woud drop the rear too low. The shackle would of given you 2", but people MOST of the time only use the hangers to achieve the other 2" for a total of 4" in the back. That may be your problem, not sure tho. Quote Link to comment Share on other sites More sharing options...
misterp Posted April 3, 2008 Report Share Posted April 3, 2008 (edited) The front is fine, in fact you actually improved the CV joint angle; however you will have worsened the tie-rod angle and the truck will wander a lot on uneven road, the fix for this is the DJM tie rod flip kit if you have an extreme case of this (I do as I also have lowering keys as well). Also remember that in your front drop you did not change the angles on the front driveline, so it's still stock. The vibration is from the rear pinion - when you change the location of the front spring eye you seriously alter the rear pinon angle in the AWD SS trucks, especially if you use the McGaughy's piece. If all you want is a 2" drop in the rear then reinstall the factory front hangers and use longer drop shackles. If you choose to fix the rear vibration issue your only course of action will be to shim the rear axle, mine was so far off that no shims could fix it and we needed to cut the axle free of the vehicle and re-weld the spring perches to rotate the tube downward 9+ degrees; I would not recommend this, I never got all the shakes out, there's still a hint of vibration at exactly 72-mph. Also in an AWD truck raising the front spring eye makes the rear squat on accell and long story short the truck is slower in ET. I investigated the situation with my truck with chassis software & I'm pretty sure that not only did I have to correct the pinion angle (which we did) but I also need to lower the engine & transmission about 1" to correct the front yoke angle on the rear driveline. Mr. P. Edited April 3, 2008 by Mr. P. (see edit history) Quote Link to comment Share on other sites More sharing options...
Stanley Posted April 5, 2008 Author Report Share Posted April 5, 2008 The front is fine, in fact you actually improved the CV joint angle; however you will have worsened the tie-rod angle and the truck will wander a lot on uneven road, the fix for this is the DJM tie rod flip kit if you have an extreme case of this (I do as I also have lowering keys as well). Also remember that in your front drop you did not change the angles on the front driveline, so it's still stock. The vibration is from the rear pinion - when you change the location of the front spring eye you seriously alter the rear pinon angle in the AWD SS trucks, especially if you use the McGaughy's piece. If all you want is a 2" drop in the rear then reinstall the factory front hangers and use longer drop shackles. If you choose to fix the rear vibration issue your only course of action will be to shim the rear axle, mine was so far off that no shims could fix it and we needed to cut the axle free of the vehicle and re-weld the spring perches to rotate the tube downward 9+ degrees; I would not recommend this, I never got all the shakes out, there's still a hint of vibration at exactly 72-mph. Also in an AWD truck raising the front spring eye makes the rear squat on accell and long story short the truck is slower in ET. I investigated the situation with my truck with chassis software & I'm pretty sure that not only did I have to correct the pinion angle (which we did) but I also need to lower the engine & transmission about 1" to correct the front yoke angle on the rear driveline. Mr. P. I'll switch to a rear schakle and see if the vibration goes away. I guess my vibration is closer to 70 to 75 mph. If iI could find out what the acceptable range of angles were I could shim the pinion accordingly. Quote Link to comment Share on other sites More sharing options...
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