ok so its not a major malfunction but heres the backstory... a few months back i finished my 462 swap. i bolted it up to my th-350 and torque converter. the problem is it pulls great when i shift gears manually (1st-2nd-d) but doesnt seem to downshift when i stand on the gas pedal in the drive gear. before, when i had the 350 engine in there, there was a noticable downshift at slower speeds and highway speed that is now missing. since my fluid level seems to be fine (checked hot) im guessing it has something to do with my kickdown cable. it is connected to the pedal and when i got it all back together i believe i set it properly (pushing the pedal down to the floor). the only two issues i see with it is there is a leak at the trans where the kickdown cable is (bad o-ring), and i reused my throttle cable. im dont think the leak would cause the issue so that leaves me with the throttle cable, unless im missing something else altogether :idea2: would the longer "stretch" of the throttle cable cause my downshifting issues? it does seem after the swap that my gas peddle sits a little higher. im thinking this doesnt allow the kickdown cable to fully engage?
Sounds like a detent cable issue. You are looking in the right area. The only other thing I would check is the modulator valve and its vacuum plumbing.
it shouldnt be the modulator, that only controlls up shifts. make sure the cable didnt come loose or broke off the lever inside the tranny. :beer
Have someone floor the gas. Check to see if there is any slack in the detent cable. It should reach the end of its travel at WOT.
You may want to check the vacuum modulator as this is the TV pressure control, and IMO does control partial throttle downshifts. My guess is that the vacuum lines are not getting vacuum to the modulator. Start the engine up and pull the line on the modulator and check vacuum with gauge. If good, then modulator may be bad.:bglasses: Kickdown rod (or cable) just controls WOT kickdown, nothing else.:Smarty:
yeah thats what im checking for. when i push the pedal to the floor, no downshift ou: the trans operates fine when im just cruising.
That will be awkward looking, since it's off the pedal inside the car and there's not much room for somebody to fit in there if someone else is sitting in the seat pushing the pedal.:laugh: It's a one man job, just did mine over again last weekend after tweaking the throttle linkage. Move the clip on the detent cable as close to the firewall as possible without moving off the solid part of the cable. Slowly push down on the pedal until you hit the floor, adjustment is done.
What would happen if the vacuum modulator actuating rod or pin is stuck at the mid point of it's travel? Your upshifts would be abnormal and so would the downshifts, as when coasting the modulator has max vacuum and should return to the closest position to the modulator diaphragm. If it doesn't return as it should it will certainly cause upbrupt downshifting. I know this probably is not the problem in this thread, but it certainly should be mentioned.:bglasses:
You are absolutely right Artie:laugh: It does depend also on how big you are too. If you're a Doug Hecker size dude with size 15EEE's, there is gonna be a problemou:
so i went to check again and when i floor it with what should be wot, i still got about two inches before it reaches the clip on the kickdown cable. not a good thing i imagine. is there a way to move the clip back up to "reset" the downshift point or would it have to do with the 350 throttle cable being used with a 455 engine?
Yes, move the clip as far down the cable as possible. If you look at it closely, you'll see where you can use a pair of needle nose pliers lengthwise to squeeze both tangs and slide it down the cable towards the firewall. Slowly apply pedal pressure until WOT is reached. Adjustment is done:TU:
