Another tip on frame ID is how the transmission crossmember is mounted. Two tabs drop down to enclose the U-channel ends of the crossmember on WWII models and the CJ-2A. This photo shows a drop-down extension fitted to relieve driveline angles, but the basic two-side-bolt, one-center-bolt design is retained. The CJ-3A and later models use a similar crossmember, but it is bolted flush and flat at the frame with two bolts per side pointing straight up. As with almost any Jeep, the later crossmember can be retrofitted to earlier versions by drilling some holes in the frame.