[rotorwrench]

The convertible cars and station wagon types had a different frame to beef up the structure so the shift solenoid won't fit in the normal position on those. Ford made an adapter rocker plate that under slung the shift solenoid for those X cross member frame type Ford cars. The straight cross member cars all used the same solenoid. Most of the chassis parts catalogs illustrate the rocker adapter.

I've heard of problems with the lock out rail assembly inside the transmission but it should be OK if it is going into full lock out unless it's not going back into position when selected to OD. It should fully retract when the cable is pushed back in. The side cover has to be pulled out to see if the rod retracts all the way back into the gear compartment of the transmission. This is where the reverse lock out lever pushes it back when the transmission is shifted into reverse. When shifted out of reverse the rod pushes back into that part of the transmission case. There can be an issue with the balk ring getting out of place but it's only under certain circumstance that it can happen. There is a procedure in the overhaul manual to reset it but the symptoms are different.

Someone already mentioned the pawl check. It should move in and out anytime the cable is pushed all the way in. Pulling the cable out locks it with the shift rail to stop engagement. The solenoid should pop out quickly when bench checked or when connected fully to the electrical system with governor circuit grounded under test. It has a push out coil and a holding coil in there to lower the amp draw while it's activated.

I have a fully updated R10 overhaul instruction in my 1949 through 51 Lincoln Mercury overhaul manual. The only differences is that the 49 though early 51 Mercs had the larger half bell, and the larger input shaft. Both types had the lock out switch in the governor circuit. The late 51 and up Merc transmissions had no bell, smaller input shaft, and no lock out switch. Ford eliminated the lock out switch as redundant in the 51 & later transmissions. The Lincoln cars used the R11 OD based on the T85 transmission. Ford all had the basic 259 series type transmission but they all are similar between Ford and Mercury cars. In 1952 & 53 Ford & Mercury cars both had the same basic transmission.