Re: Question about rear driveline angle shims
Re: Question about rear driveline angle shims
SY2455 said:
The reason they use the angle shims stock is because under hard acceleration your drive angle will change to what your are seeing without them being there. The rotation of the rear diff that you are going thru without the shims is more than likely not good as you are going past the what the truck were set up for. PS. this is the short version..
I understand that this is the case in specailly set up drag cars where the car will actually squat 6 " on hard accel, therefore when the rear axle rotates due to extreme torque coupled with the loading of the rear springs, the axle's snout rotates to be in more of a straigt line with the tranny's (or T-case's) output shaft. But this is not the case with Chargerman's Syclone. The rear end does not squat more than 3" (if that) on hard accel and the added spring leafs we added actually make the ride more stable and somewhat harder. This being said, however, the Syclone and Typhoon do not have super soft springs (at least Charger's doesn't now) nor do they have 700 hp. 300hp and 400 torque is puny in relation to such a modest amount of driveline angle.
Also, moving the rear axle upwards - to be on a more level horizontal plane with the t-case output shaft is removing the need for the (normal) use of pinion shims since it is infact altering the geometry of the rear end. In fact the need for those pinion shims seem pretty iffy to me anyway. Most auto manufactures simply welded the axle spring perches on the axle housing at the correct pinion angle. I've dealt with this issue in deciding to move or not move a rear axle forward 12 inches. Same problem arises when lifting or lowering a vehicle by using suspension lifting or lowering methods. Any altering of the lift and or distance of the axle away from or towards the output shaft of the transmission or transfer case will also change the angles involved- its simple geometry - you can't change the length of one leg of a triangle without also changing the angles opposite and adjacent to that leg, and also it may effect the length of another leg of the triangle, depending on what parts are modded.
Removing the shims has brought everything into straighter alignment...obviously. The only thing we've found that may need to be changed is driveshaft length since the slip yoke seems much closer to the transfer case snout -1" clearance. And from the added rotational leverage of the 2" block, the vehicle has axle hop, so traction bars may be adviseable.
Also, after reading the previous posts about wheel centering in the wheel well, I can say the wheel centers were with in an 1/8th of an inch and they are pretty well centered. without the shims.
