Installing an AOD Transmission into a 1941-1948 Ford

There is no doubt, especially with today's gasoline prices, that an overdrive transmission just plain makes sense whether you are traveling to a rod run or are simply on vacation in your fat-fendered Ford. While many of these vehicles are powered by a GM drivetrain, there is a growing contingent of rodders who choose to put a Ford powerplant under the hood of their Blue Oval-mobile. Besides installing a late-model Ford engine in an early Ford chassis being a challenge in the first place, including a larger overdrive transmission makes it more of a headache than anything else. Henry had greatly strengthened the chassis of these vehicles with a pretty hefty transmission x-member that was a great improvement back in the day. Sadly, what solved or at least greatly reduced chassis flex back then, made it practically impossible to physically mount a wide transmission in a narrow space today.

Morfab Customs, Inc. who has manufactured a kit for installing a GM700R4 tranny in this application for years, has now expanded their product line to cater to the Ford faithful. Like the previous kits, the AOD (automatic overdrive) kit can be installed with or without the body in place, but is being shown with a bare chassis for clarity. An added bonus of this particular application is that the kit includes the master cylinder mount, which is drilled for both standard master cylinders or for those utilizing a power booster. For the most part, this kit is a true bolt-in, requiring no welding. Instructions included with the kit show you where to cut away the original crossmember, grind off a few rivet heads, and then bolt the replacement pieces in place. It just doesn't get much easier than that.

Since the transmission crossmember is what provides the majority of the rigidity in an early Ford frame, you can't just arbitrarily start cutting away metal to make room for a larger transmission. Additionally, if you are retrofitting an overdrive tranny into an existing rod, you really don't want to be required to remove the body from the frame or have to do extensive paint touch up.

Follow along as Keith Moritz installs a Morfab Customs AOD overdrive transmission kit into a 1941-1948 Ford chassis.

Step 1. The first step is to remove the brake master cylinder and pedal. If this is being done on a drivable vehicle, be sure to drain the brake fluid before this step.

Step 2. Body mount braces that are attached to the outer frame rails and the x-member need to be removed temporarily. They will be reused, so don't trash them. They are riveted in place from the factory, so grinding the heads off and then knocking them out is the typical procedure. On this particular frame, the body mounts have already been removed and then reattached with bolts and nuts. Regardless of how they are attached, they need to be removed.

Step 3. The stock transmission mount needs to be removed. Moritz begins this process by using a small grinder to grind off the rivet heads. With the heads ground off, a hammer and punch can be used to drive the rivets out of their original location.

Step 4. Theoretically, with the rivets removed, the factory transmission mount would fall right out. However, this frame is a minimum of 60 plus years old, so it may be a bit cantankerous. If this is the case, some persuasion from a Ford hammer (aka BFH) may be appropriate.

Step 5. This is essentially what the process would look like from the topside with the stock transmission mount removed.

Step 6. Not that it has to be, but the chassis has now been inverted to make removing a portion of the transmission mounting plate easier. Measure back 1 1/4 inches from the second pair of rivets from the front of the bottom of the factory mounting plate and then scribe a line across the plate.

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