A 2008 Ford Fusion equipped with the 2.3 liter engine and FNR5 transmission was setting trouble code P0735 after overhaul. The transmission was removed and disassembled for inspection. The direct fifth gear drum was air checked and it was found to be leaking. The drum was replaced and the transmission was reassembled and installed back into the vehicle. During the road test the MIL Lamp came on and P0735 was once again set.
Since the technician was convinced that the problem was not inside the transmission, they decided to remove and inspect the secondary valve body; refer to figure 1 above.
Upon inspection of the secondary valve body, the reduction fifth clutch shift valve and bore were worn out; see figures 2 and 3.
The secondary valve body was replaced and the vehicle was taken for a road test. The transmission operated normally and the P0735 did not return.