Hey guys, TH400 not kicking down to passing gear. Voltage to the trans plug is 11.7. Is that enough? It has the 2 wire plug but I only have the red going to it. I dont think that should make a difference, or do I need to change it to a single prong solenoid?
Yes, that is enough voltage, and a single wire is all you need. If you apply voltage to that transmission terminal, you should be able to hear a click from the solenoid every time you touch the terminal, and remove the wire. Use a jumper from the + battery terminal for simplicity. If you cannot hear a click with your ear at the pan, the problem is either the wiring inside the pan, or the solenoid. In either case, the pan needs to be dropped. The solenoid is easy to replace with 2 bolts.
The case connector has 2 terminals. The vertical is for the kickdown detent, and the other (horizontal) is for the TCS (timing control modulator) if you drop the pan, one wire connects to the bottom of the valve body, and the other to the solenoid for the kickdown. Internally, it is a tan wire for the detent and a white wire to the TCS. If put 12V to the switch and it does not click, it could be grounded. It may or may not blow a fuse. I use a test bulb to provide load, prevent blowing fuses and get a completed circuit indication.
That could be the problem. I'm pretty sure the wire from the kickdown switch at the pedal is going to the vertical slot of the plug on the tranny.
I meant the kickdown switch wire goes to the horizontal side I think. I will have to double ck that though.
That is the correct spade. You never know what you can find. The wiring may be reversed inside the pan.
I've also found a bad connecion at the bulkhead connecter. This was from the factory as the original owner said it was this way new & no one could find the problem. Turns out the wire was never pushed in all the way & when I did push it into place there was still no current passing. No matter what I did would not pass voltage. So to repair & not waste anymore time I cut the wiring on both ends & soldered them together & filled the hole with dum-dum. 1st. time it worked since '73. Tom T.
Yep. Never stop troubleshooting until you have found the problem. And a good working repair, is a proper repair, in many cases.
The OP has voltage at the transmission, so while that can happen, if the OP's first post is accurate, that isn't the case here.
Yes it says I have voltage at the plug on the tranny. Just didnt know if the tranny had both wires originally, is that setup were the wires would have to be switched and the horizontal prong goes to the solenoid? It felt like it kicked down once or twice but hard to tell when you stand on it with the 455. I've been changing the shift points figuring maybe that had something to do with it also because if you were already to high on the rpms the tranny wont let it kickdown.
If you can't hear the solenoid click emanating from the pan, it isn't working. Only one wire is necessary. The second line goes to an oil pressure sender on the valve body, it has nothing to do with the kick down. If you can't hear it click, the pan has to come down to diagnose it further.
