1949 -50 Mercury overdrive trans case interchangeability
 

I've got a '49-50 Mercury overdrive transmission with a cracked case. I've been rummaging through my spare parts and I've got an empty case that may be correct that's gotten pretty wet. I also have a '46 or so Lincoln Zephyr overdrive trans, obviously the tailshaft section is totally different, but the front half of the case looks like it could be the same. Does anyone know for sure what I can use here? I've attached some pictures of what I have because everyone loves pics.

Re: 1949 -50 Mercury overdrive trans case interchangeability
 

I did the opposite, putting the Lincoln OD unit on a 50 Mercury case. This will raise the solenoid closer to the floor.
Anyway, all of the holes don't line up. Use a Mercury gasket against the case to see the difference.

Re: 1949 -50 Mercury overdrive trans case interchangeability
 

I guess you wanted to go to a torque tube? Were you able to make it work?

Re: 1949 -50 Mercury overdrive trans case interchangeability
 

The half bell case was used from the beginning of the 1949 model year up to sometime in the early part of 1951 for Mercury cars. It was likely around February of 1951 or there abouts.

The Lincoln case may work but make sure there wasn't some difference between the late V12 bolt up and the smaller Ford/Mercury little brother. There are variations in the way the OD tail housing was made in some years. The gears in the transmission housing should be interchangeable even though Lincoln had close ratio gearing. The internal lock out control for reverse is important too. It will have to match the Mercury housing.

A corroded case may be OK but it depends on where all it is corroded. The problem areas are the same as for the older Ford & Mercury cases. Cracks around the front counter shaft bore and extreme wear on the rear thrust surface of the counter shaft. If it has bad flange pitting then a person can use Devcon plastic steel to level it back out as long as there is still a flange to work with.

Re: 1949 -50 Mercury overdrive trans case interchangeability
 

We’ve got a few extra core 49-50 Merc overdrive cases over in the core room. If you can’t find one elsewhere, let me know. We’re taking our vacation break this coming week so you’ll have to email me, or call after the 30th.

Re: 1949 -50 Mercury overdrive trans case interchangeability
 

Thanks for the replies, my crusty case turned out to be a match so I got it disassembled and sand blasted. Should be back in business soon. It's not hoarding if you wind up using the parts right?

Re: 1949 -50 Mercury overdrive trans case interchangeability
 

Semi related question, is the bushing inside of the second (intermediate) gear replicable? I haven't found it available separate.

Re: 1949 -50 Mercury overdrive trans case interchangeability
 

I've never seen a replacement part listed for the bushing inside the 2nd gear. It's pretty thin and getting a new one in there without damage could be problematic. Reaming could also be difficult with such a large bore. Some of the late replacements don't even have the bushing in there. This may be the reason Mac VP has been using the 81A-7102 2nd gear as a replacement for the later 51A-7102 part.