This question is for my stock '71 Stage 1 with a TH400. At normal cruising, what is the typical MPH max downshift point from 3-2. My car currently will not downshift 3-2 above 55 MPH. Seems to me it should be capable of a 3-2 downshift up to around 70 MPH. Am I wrong to think that? Everything is hooked up correctly and I have adjusted the kick down switch per the shop manual.
I would think it should downshift at a higher MPH. Try bypassing the downshift switch with a jumper and toggle switch. The governor and valve body calibration and modulator setting can affect this.
Before you do that, key on, work the switch by and hand and listen for the solenoid to click in the trans. It's faint but can be heard. If it doesn't work, could a few things. That circuit is tied to the radio fuse or could be the wiring and/or switch...or solenoid.
Kickdown switch is on the gas pedal bracket? 1. I've seen a bunch of cars that won't kick down properly because the steel rod of the gas pedal bends. Kickdown and WFO at the carb are both affected, there is excess slack between rod and throttle cable.. 2. Does the manual explain that you will not get correct adjustment unless you first pull the switch mechanism ALL the way to the limit of travel before putting the gas pedal to the carpet? The switch is "self adjusting" but only when first put into the initial position I pull the switches apart for cleaning and inspection. The grease inside is always ancient and hard. The brass contact drags across the ridges of the shoe to provide adjustment. That's the "ratcheting" noise you hear when the switch adjusts. If the shoe ridges have worn-out, you'll probably need a new switch. Not overly common, though.
Thanks Schurkey. It makes sense to remove and inspect the switch before trying the other suggestions. And I bet it could use some grease, if not full replacement. I do have a spare switch if I have to go that route.
My dad's car wasn't working at all Last week I checked the wire with a test light and nothing. So I fixed it and man ohhh man he has 373 gears so when u are up to speed and nail it.....she wants to take off and fly away talk about a difference..
Probably one of the easiest things to diagnose. just start at one end or the other and find out where you are losing continuity. The first thing to do is run a jumper from the battery positive and touch the connection at the transmission. You should hear the solenoid clicking every time you touch the spade connection at the transmission. No click, you have to drop the pan, it's either the wiring inside the pan or the solenoid itself. Hear the click? Yes, than hook up a test light at the wire end that hooks at the transmission. Turn the ignition switch to run and manually trigger the gas pedal switch, the light should light every time you trigger the switch. If not check for power at the gas pedal switch. Do a continuity check between the gas pedal switch and transmission connection. Check the switch itself by putting an ohmmeter across the switch contacts and actuate the switch. No power at the switch, check the fuse. Find out where you are losing the 12 volts.
Just to clarify my issue, the kick down works just fine at 55 MPH and below. It is above 55 MPH when the kick down will not activate.
You need to do the tests I outlined. The kick down can happen hydraulically and electrically. Rear gearing, converter, and modulator setting can all influence when that hydraulic kick down occurs. Flooring it should always trigger it electrically. Don't assume the electric part of it is working. Verify it.
Thanks Larry. I plan on getting around to this on the weekend. In the meantime, can anyone comment on why the original switches came with an external resistor and replacements do not? I've attached a couple pictures.
I have seen that a few times before, never on either of my cars. Resistors lower voltage. Not sure why you would need to do that unless the solenoids had lower voltage requirements?
