l have a newly restored 1964 Mercury Mont Clair Marauder and need to know how to troubleshoot the Fordomatic tranny.All advice would be greatly appreciated. Thanks.
Tranny shifts into every gear but drive. l would buy a manual but the only one that l can find is $65.00 and with only the one problem it does not seem to make any sense. Vacuum diaphragm and lines are okay.

It would be nice to know what the problem is that u have with the transmission. Troubleshooting this trans- or any other-depends on what the problem is. Is it a engagement problem, shifting problem, slippage? It begins with an understanding of basic trans operation, powerflow & controls. l suggest getting a shop manual for the vehicle. You can probably find one online or at a swap meet.

Add-on to ur update: If l remember correctly, this is the dual-range 3 spd trans. In one Drive range the trans shifts 1-2-3. In the other Drive range, it starts in 2nd & shifts to 3rd only. Second gear start was used for take off in snow, etc. Low was just low. Make sure u try both ranges of Drive. Check if reverse is ok. In 3rd gear the high clutch is applied. Same clutch is also on in reverse with the low-reverse band to get reverse. If reverse is ok, then make sure the kick-down rod is adjusted correctly or not stuck partially down. From there, no 3rd gear would be governor, accumulator or 2-3 shift valve.

to sh752 he cant change from auto to manuel trans can he thats almost what it sounds like he was going to try?

My 64 Galaxie has the same transmission, but it is not called a FordOmatic because that would be a 2 spd auto, u have a Cruisomatic trans which is the same as the FMX in later years. Maybe the true problem is u have a 2 spd trans in place of the stock 3 spd green dot drive Cruisomatic. All full size Mercurys in 1964 came standard with a 390 either a 2 barrel or 4 barrel carb. They also came standard with a 3 spd auto in the column. There were no 2 spds available for full size Mercs. l would check that trans for an ID tag. You should see a C4 number to indicate year C=60-69 / 4=year 1964. That old Cruisomatic is really one tough trans & used up until 1967 on all big blocks. That Fordomatic trans was used with 292 Y blocks 8 is in full sized Fords in 55 to 62 & will fit other motors.