TO-35 Transmission/Rear End on F-40

Can I put a TO-35 transmission and rear-end onto my F-40?

If you have a standard clearance Ferguson 40, the TO-35 transmission and rear axle should bolt up with no problem. There was a change in the ring gear in the TO-35 models. Those prior to serial number 169 467 use a 40 tooth ring gear and those from serial number 169 467 and up use a 37 tooth ring gear. Since you are changing the entire rear axle, that should make no difference however, there were different tractormeters to go with each of these ring gears. There were also changes in the main shaft gears in the transmission. Tractors prior to serial number 171 549 have 60 exterior teeth on the Main Shaft gear, and those starting with serial number 171 549 have 45 exterior teeth. The reverse shaft gear on tractors prior to serial number 171 549 have 17 and 21 teeth and those beginning with serial number 171 549 have 13 and 21 teeth. Again, since you are changing the entire transmission, there should be no problem. I am not sure any of the F-40’s had the later style gears in the transmission. I believe those gear changes effect the speed in reverse. There may also be some differences in the clutch but there is no reason to change it if the F-40 clutch is working properly. F-40’s and early TO-35’s used a dual clutch with Belville springs on both the main and PTO clutch. Later model TO-35’s use a clutch assembly with a series of coil springs rather than a large Belville spring on the main clutch. The clutch assemblies can be interchanged as complete units and either clutch should mate to the transmission input shaft. If your 40 is a Hi-40 there are a few different gears in the transmission and PTO than would have to be changed on the TO-35 transmission. This will keep the gear rations and speeds with the larger rear wheels correct. That information is detailed in the last issue of Ferguson Furrows where I answered a question about converting a Hi-40 to a standard clearance version. Bottom line, you should be able to use the TO-35 transmission and rear axle on your F-40. Just be aware of possible differences in the transmissions and rear axles of some of these tractors that will affect gear speeds.