1955 Crown Vic - small or medium transmission?

[delco1946]

Hi All,

Quick question, looking to buy a rebuild kit for a 1955 crown victoria 292 foromatic. Macs is showing me two options for 1955 - small and medium case transmissions. How do i know which i have? The medium option, under part fitment doesn't actually show it for 1955 (but then why is it showing as an option when the main site has me select 1955 FORD)?

https://www.macsautoparts.com/ford_m...ord-only.html#

Here is a link - is this the right kit? Also, let me know if all these seals are truly "standard", which the guy hinted at. I was going to buy this kit to send to the mechanic that will overhaul my tranny but he said its comparable to a C4 or C6 stacked transmission and he should have the parts/seals/etc, but i was still thinking it wise to get what "i know" fits the car? Perhaps i am worrying too much?

Thanks!

[delco1946]

And also, not to ignite a war - but would i still use a type A modern equivalent fluid (AKA Mercron II/III) or do rebuilt trannys and/or newer materials need some other fluid? I thought i read somewhere that rebuilt trannys often have a different material/metal clutch plate (or something like that) that requires a different fluid to avoid damaging the different metal? (i don't recall if it was a brass plate that is softer perhaps and damaged but certain viscosity/frictional fluids???).

I'm positive if i don't say anything - he would just use type F which i don't want in my fordomatic unless there is a justified reason (such as the kit altering its innards).

[dmsfrr]

I too believe that the fluid type to be used depends on what materials are used in the transmission. (but what I know about transmissions might fill a thimble)

When I asked the shop that did my '55 air-cooled Ford-o they said, "Mercon".
.

[KULTULZ]

If the tech works in an actual TRANS REPAIR SHOP, I would let him source the kit. It may need more than the kit contains when it is on the bench. You will also have a warranty on the trans whereas if you bring your own parts, you may not.

And he will be able to source most likely a better quality of kit.

As for the fluid, it will require MERCON IV, which was discontinued by FORD some years back and went to MERCON V which is a synthetic. The original fluid (DEXRON II/III) is still available aftermarket (the shop most likely has it in drums). I would talk with the tech to see what is the current fluid recommendation.

The FORD-O-MATIC and MERC-O-MATIC have differing main case sizes.

[delco1946]

Excellent point. He implied not to worry about, and he has rebuilt "stacked transmissions" (no idea what that means), but he hadn't rebuilt a fordomatic - so i was just worried if they're more different that he might think. He had excellent reviews and equally excellent price so i guess i'll just trust!

[Daves55Sedan]

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The medium case trans was used in T-Birds and Mercury cars with V8. If your drivetrain is factory original, you most likely have the small case Ford-O-Matic with air-cooled converter. The 292 is likely not original unless the VIN shows "P" code for the engine. Rebuild shops started supplying the 292 as a replacement for the 272 several decades ago.
If your trans pan has one bump-out that goes all the way to the corner, it is a small case. If the trans pan has a small bump-out near the middle on the side of the pan, it is a medium case.

[delco1946]

Thanks Dave. it was originally a 272. I'll check my pan this week.

[Daves55Sedan]

You might be able to find type "A" trans fluid at a farm supply store sometimes. I am using the modern asbestos/cement fiber clutches in my Ford-O-Matic and Castrol Dex/Merc (Dexron/Mercon) fluid in mine for decades. Shifts as smooth as silk. BTW, Dexron was the OEM replacement for type "A" back in the day.

[rotorwrench]

Type A does not exist in it's original form since whale oil is no longer used for this purpose. Type A replacement was type B which was used in the 2-speed Ford-O-Matics for a while. It is the same as the original Dexron that GM put out. All the Borg Warner types made for or by Ford were changed over to the Type F in the late 60s due to problems with slipping of the metallic plates. Steels & Bronze plates were used clear up into the FMX era so Ford developed type F to make the warranty problems go away. The C6 was the first one to start using modern composite plates so they can use Dexron/Mercon along with all the transmissions after the FMX including the AOD.

Type F will make any transmission lock the clutches up better and quicker unless the composite plate are already well worn. A lot of drag racers used Type F in the Powerglide transmissions due to this reason.

[paul2748]

As mentioned above, let the rebuilder recommend the type of fluid.

[rotorwrench]

My old rebuilder took over his fathers transmission shop. I learned a lot from him and started doing my own transmissions. Their shop had had a contract with the local USPS taking care of the mail carrier vehicles that had the cast iron Cruise-O-Matics for many years. It's getting harder to find guys that have much experience even with the FMX transmissions. It's been a long time since a lot of them were on the road and even longer for Ford-O-Matics.