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rotorwrench · 02-19-2020, 10:49 AM

What some folks refer to as a kick down rod & lever is not quite correct. There is the gear selector lever and a throttle control lever. These transmissions use the throttle control lever to control pressures inside the transmission. Kick down will occur due to the spike in pressure when you floor it but it's not there just for kick down. Since there is no vacuum modulation like the 61 & later cars have, the shifting pressures had to be controlled through the linkage with the engine throttle control. The control mechanism behind the carb is a bit more complex than a kick down. It has to be properly adjusted to get correct shift control throughout the range of operation. As you push down on the throttle the TV valve (short for throttle valve), constantly increases transmission pressures as the throttle is opened up. The governor is set for shift points but it also has to have the correct pressure to shift properly. Too little pressure and it will slip. Slippage will kill the plates in these transmissions so adjustments have to be done a little bit at a time to adjust for a faster harsher shift down to a slower sloppier shift. You want somewhere in between when adjusting the TV rod linkage.

If the transmission has internal leaks due to bad o-ring seals, worn piston ring seals, bad servo diaphragms, or loose & leaky tubes then the transmission will have shift problems. Guys that know these transmission well have to diagnose off what the shift characteristics are. Generally the first thing they will do is a pressure test. A person needs the tech manuals for the transmission they have. There are a few shops out there that specialize in these units due to the number of T-birds and popular collector mid 50s Ford cars & trucks that have them.

The AOD is an option but the kits are expensive. These transmissions are distant relations to the old Ford-Os in that they have ravigneaux planetary units and still use a cable to control the TV valve but they have much more modern technology with the big advantage of overdrive.

02-19-2020, 10:49 AM	#27
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,436	Re: '54 / '55 Fordomatic ID ? What some folks refer to as a kick down rod & lever is not quite correct. There is the gear selector lever and a throttle control lever. These transmissions use the throttle control lever to control pressures inside the transmission. Kick down will occur due to the spike in pressure when you floor it but it's not there just for kick down. Since there is no vacuum modulation like the 61 & later cars have, the shifting pressures had to be controlled through the linkage with the engine throttle control. The control mechanism behind the carb is a bit more complex than a kick down. It has to be properly adjusted to get correct shift control throughout the range of operation. As you push down on the throttle the TV valve (short for throttle valve), constantly increases transmission pressures as the throttle is opened up. The governor is set for shift points but it also has to have the correct pressure to shift properly. Too little pressure and it will slip. Slippage will kill the plates in these transmissions so adjustments have to be done a little bit at a time to adjust for a faster harsher shift down to a slower sloppier shift. You want somewhere in between when adjusting the TV rod linkage. If the transmission has internal leaks due to bad o-ring seals, worn piston ring seals, bad servo diaphragms, or loose & leaky tubes then the transmission will have shift problems. Guys that know these transmission well have to diagnose off what the shift characteristics are. Generally the first thing they will do is a pressure test. A person needs the tech manuals for the transmission they have. There are a few shops out there that specialize in these units due to the number of T-birds and popular collector mid 50s Ford cars & trucks that have them. The AOD is an option but the kits are expensive. These transmissions are distant relations to the old Ford-Os in that they have ravigneaux planetary units and still use a cable to control the TV valve but they have much more modern technology with the big advantage of overdrive.