TRANSMISSION SWAP - JULY 2010
A couple of years ago, at Carlisle, one fellow pulled in with his S&H Torino. With New York plates, he was telling us that he had a fuel injected 351 Windsor, and a 4 speed automatic overdrive - yes - 4 SPEED OVERDRIVE automatic.
He said it was pretty well a bolt in project, but nothing is ever "bolt-in"
I did quite a bit of research, and wound up purchasing a 3 DVD set on "how to teardown and rebuild a Ford AOD". From the DVDs, I determined that an AOD (non electronic) from an 89 or 90 full size Ford or Lincoln would do.
I managed to secure for very little money a super looking Ford AOD from an 89 Crown Vic, which, are still essentially Torino frames, and for that year, still came with the 351 Windsor engine.
I stored the AOD over the winter, and this summer, I got brave. I jacked up the car high off the driveway, and started taking things apart.
First off, the FMX 3 speed vacuum lines, fluid, shifter linkage, speedo cable. Then I dropped the driveshaft, and removed the transmission cross member.
I had to remove the starter as well. Disconnecting the battery is a given, but I will mention it anyway. The block plate is the same for both trannys.
I opened the torque converter (TC) inspection plate, and disconnected the TC from the flexplate. I had no choice but to cut the exhaust pipes forward of the trans mount for clearance to lower the FMX. Before removing the bell housing bolts, I drained and SAVED the FMX fluid, in case I had to reinstall it.
Once I had everything clear, my neighbour and I, using a big jack and some wood blocks, supported the FMX from the pan, and I loosened the bell housing bolts.
We then lowered the FMX down and away, and rolled it into my garage to measure it against the AOD.
Well, it turned out that the FMX and AOD are nearly identical in length. The only snag I ran into was that the bosses on the AOD bell housing are fatter than the FMX, so longer bell housing bolts are needed. No Biggie.
Now for reinstalling. The shifter linkage and speedo gear and cable from the FMX were a direct fit to the AOD, as was the transmission mount and cross member. The only mod necessary is the following. The slip yoke that came with the AOD was slightly narrower than the FMX slip yoke, so the spider of the u-joint would not "swing in". Speaking with a mechanic-friend of mine, we simply removed 1/32" of material from the inner surface of the AOD slip yoke, just enough to allow the spider to swing in and the bearing caps to be pressed on. Problem solved. I later found out that a "conversion u-joint" can be used to accomplish the same thing.
Reinstalling was basically the reverse of removing. We wrestled the AOD into place, and by taking 2 long bell housing bolts and cutting the heads off, we used them as guides to get the transmission in place for easier alignment. Once we got close to the dowel pins, all the bell housing bolts were started into the block, and tightened a bit at a time to "pull" the transmission into place. Make sure the TC is fully seated! This is important! All the bell housing bolts were torqued in, the rest of the running gear replaced, the exhaust system reconnected.
Now, the AOD shifts not by vacuum, but by pressure, which is controlled by the THROTTLE VALVE CABLE. LOKAR makes a cable kit for this with all the brackets and install instructions. I had to make a bracket on the carburetor end, but the cable installed correctly. There is a calibration tool given to set the line pressure at idle to 33 PSI (very important).
So, once everything was installed, and ready, I filled the tranny, and while the engine was running, I would run thru the gears (car on jacks still) to get the fluid to pump thru the transmission. It takes 14 quarts, or what I did , I used a 2 litre pop bottle - 7 fills did it. Once full and warm the line pressure was properly adjusted, and then road tested.
It drove like a different car. Overdrive kicks in at around 40 mph, and on the highway, at 60 MPH the RPMs are at 2100, where with the FMX it would be around 3300. I have a standard open differential with 2.75 gears.
I tested it mostly close to home, but the maiden voyage was the 120 mile drive to the NSRA Hot Rod show in Burlington, Vermont, last September. The car ran flawlessly. Quiet and smooth, pulled up and down the Vermont hills in 4th with no issues. On the return trip, I was able to get an accurate reading on fuel mileage - I drove back 125 miles on a quarter tank, which for a 4000 pound car is not bad at all.
So, that is my experience. Its not a job for the weak hearted, but can be done in a driveway over a weekend with success.
Car up on jackstands about 2 feet. Braced on some nice flat pieces of lumber and some blocks under the tires, just in case.
Slip yoke from the AOD on the drive shaft; AOD with the TC painted, note the steel cable - thats the Throttle valve cable
FMX front and side views. Note from the front, the FMX and AOD are identical except for the inspection plates.
Exhaust pipes cut.