Transmission woes

chiefdave

chiefdave

Member
The OD trans in my '49 has started to stick in gear on occasion. Placing the shift lever in neutral with the engine off and rocking the car breaks it loose. I did replace the worn linkage bushings but the problem still exists. Maybe a bent shifting fork?
 
Did you adjust the shift linkage when you changed the bushings? With the transmission in neutral, meaning the shift levers are locked in their detent and the shifter in neutral the rods should be set to that length. Lengthen or shortern as needed to make them slide right in.
 
Check both of the shifter levers down on the transmission. The 49-50 Mercury levers were rolled and bent from heavy sheet metal and after many years of use they tend to crack at the 90 degree bend (where they are pinned to the shifter shafts). If this is evident on your trans, you’ll have to repair or replace them.

Your post doesn’t say which gear position that is sticking.....or is it all of them?

Another potential cause could be worn or broken front motor mounts, letting the engine settle or rock, putting the shift linkage out of alignment.
 
If it can be shifted to neutral with the gear change mechanism, it should be in neutral unless there is a lot of play in the forks or the shift levers as was mentioned. A stuck syncro or low/reverse gear shouldn't let you shift to neutral unless there is play.
 
rotorwrench said:
If it can be shifted to neutral with the gear change mechanism, it should be in neutral unless there is a lot of play in the forks or the shift levers as was mentioned. A stuck syncro or low/reverse gear shouldn't let you shift to neutral unless there is play.
Click to expand...


When stuck the lever will go into any of the forward gear positions but not reverse. Had already planned on having the trans pulled to have all of the seals/gaskets replaced. Found a NOS low/reverse fork and cam, would it be worth replacing them since the side plate is going to be off anyway?
 
It sounds suspiciously like a problem in the OD fork and rail assembly, including perhaps the connecting parts. There’s also a unique flapper lever (7292) in the side cover that is used in connection with the reverse lockout assy. This might be obvious when you’re looking at the inside of the shifter housing. Refer to the drawing below. If it’s in the fork and rail assembly, the transmission will have to come apart.

http://www.vanpeltsales.com/FH_web/FH_images/FH_trans-pics/8M-7201shiftr-hsng.jpg
 
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