Merc-O-Matic / fluid in torque converter

Detroit Flathead

Junior Member
Hello Noble Ford Barn friends,
I've got a '51 8BA with a '53 Merc-O-Matic in my '51 Mercury. When the transmission is reassembled into the car, is it necessary to put some fluid into the torque converter before assembly? Or, will it pull in the fluid from the transmission when it's started? I ask because I did this reassembly step about 3 years ago, and I cannot remember if it may have a quart in there, or if it's relatively dry. If it's dry, would I ruin this transmission trying to get the trans to fill the TC? Thank you for your help.

keywords: mercomatic, fordomatic, ford-o-matic
 
The early ones have two pumps but the front one driven by the engine should fill it rather quickly. Add fluid till full. The 51 Merc-O-Matics had the filler under the front passenger side floor mat but the 53 has one directed to the engine compartment plus a few other improvements. They were constantly improving the early ones. The fluid level is checked much the same way as a modern auto trans unit. Start the engine and set to Park in low idle position and adjust level till it's at full mark on the stick. Cycle it through the gears then recheck.
 
Great, this is good news. Thank you for the quick replies. I did not know that a '51 & '53 transmission had some internal differences.

Are these Merc-O-Matics fairly easy to rebuild? I would assume that any transmission shop could. Or am I wrong?
 
In my shop, we always put at least 1 Qt of ATF in the torque converter for lube, during initial startup and lube the pump bushing with assembly lube.
Yes the converter will fill fairly quick but that first few seconds or more, before fluid is picked up and circulated through the trans can be hard on internal components that are dry.
Would you start an engine with no oil in it then add oil right away or run a differential dry and then add oil right away, I would hope not.
Bill
 
This is a used transmission that I installed. It had been drained and refilled, and I think there's some fluid in the TC. I just wanted to confirm I wasn't going to be ruining this thing if didn't have much in there.

Yes the converter will fill fairly quick but that first few seconds or more, before fluid is picked up and circulated through the trans can be hard on internal components that are dry.
Bill
 
In my shop, we always put at least 1 Qt of ATF in the torque converter for lube, during initial startup and lube the pump bushing with assembly lube.
Yes the converter will fill fairly quick but that first few seconds or more, before fluid is picked up and circulated through the trans can be hard on internal components that are dry.
Would you start an engine with no oil in it then add oil right away or run a differential dry and then add oil right away, I would hope not.
Bill
If the 1 Qt. of oil in the torque converter is forced to the outside of the converter (do to centrifugal force) during initial start up, what is it lubricating?
 
There is nothing really any harder about rebuilding Ford cast iron transmissions compared to other transmissions.

Problem is finding someone familiar with them as they are somewhat primitive in design compared to modern transmissions of today, and many rebuilders in the field nowadays screw them up when rebuilding, because they have no idea how a transmission actually works to begin with.

If they cant plug a scanner into the car and tell them what's wrong, they cant fix it.
Bill
 
Since it has already had fluid in it, you will be ok. Just dont dilly-dally around when filling it once its running.

To answer 34PKUP. When you add fluid to a torque converter you do it through the hub.
Most converters will fill to the top of the hub while filling and then drain into the body of the converter.
The thrust washers, needle thrust bearing and sprag will get lubricated at that time, which would be dry otherwise and will have some residual lube left on them for startup.
Most newly rebuilt torque converters will be as dry as a popcorn fart internally.
If it is a used converter, it will have residual lube already there.
Bill
 
A lot of folks chuck them and change to a C4. They can be a bit sluggish till they warm completely up but that happens relatively fast on an air cooled set up. When they're right, they shift very nicely. Since they have no vacuum modulator, most adjustments for shifting characteristics are done with the throttle control linkage. This is where the newbies really get tangled up until they read up on all the OEM procedures. There are a few parts that are very hard to source new but not a lot and some of the later Borg Warner stuff can be used in them If you know the design. The guys that work on the 55 thru 57 Thunderbirds know them better than most folks. I still see used ones for sale on a regular basis in the various club periodicals & flea-pay/Hemmings.
 
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