I just put my SM420 back in the truck, and unfortunately I didn't take pictures of the rear support while still out of the truck. I just took pictures as best I could. At least it's all clean and painted
Let me know if you still have questions. As you can see, the transmission is short of the rear support crossmember. There's a plate that bolts to the crossmember with rubber strips between it and the bracket that bolts to the back of the ransmission.
