400 kickdown

[53burb]

I temporarily hooked up my remote starter switch on my kickdown switch. This is what I found out when I push the button: it will kickdown at any speed below 2000rpm, and will stay in 2nd until about 2800rpm, then it will shift into 3rd. So it will not engage above 2000rpm. Is this correct???

[ac102nv]

Depending on how the trans is setup ie modulator, govenor, and valve body....this could be correct. However, to tell a little more info is needed. When you tested this, trans was in Drive and you went to WOT...right?

[53burb]

Trans was in Drive. I didn't go into WOT. I simply pushed the button on the switch. I have it hooked up to test the kickdown. I don't have a normal switch on the gas pedal or carb.

[53burb]

What do you guys think????

[ac102nv]

Originally Posted by 53burb

Trans was in Drive. I didn't go into WOT. I simply pushed the button on the switch. I have it hooked up to test the kickdown. I don't have a normal switch on the gas pedal or carb.

This sounds like normal behavior to me. When you activate the kickdown, the trans looks at a number of input signals: vac from engine, driveshaft speed, and internal pressure to figure out how to react. At part throttle cruise what you observed is probably normal. If you try it again but with more pedal the RPMs should climb higher before upshifting back to 3rd. The more throttle, the more RPMs before upshift (to a point).

Hope that helps.

[53burb]

It helps. I just wanted to make sure it was normal. Is this adjustable at all??

[ac102nv]

Sure, you can adjust this within reason. But this is normally based on the upshift at WOT at a specified RPM. Once you get that set you can them slightly modify when it downshifts. Most people don't worry about part throttle upshift as this is the "passing gear" settings, not cruise. Hopefully that makes sense, if not or you have more ?? please post.

[53burb]

Right now I have an Eaton Rear with 4.57 gears & 29" tires. At 2000 RPMs, I am only going less than 40mph. I plan on going to 3.08 gears and 26" tires. At 2000 RPM, I will be about 50mph. I would like it to engage up to 2500rpm. I should be at about 65mph then. Is this easily accomplished??

[76bonanza]

You need to try it at WOT then push your button the vaccum at WOT is very diferent than at part throttle and the tranny will react very different. So to test what you want, go to WOT then push you button and see what how the tranny reacts.

[ac102nv]

I don't know of a way to calculate what changes are made. I'd say make your gear/tire changes and see how it acts. It's possible that the downshift point may move to where you want. The trans looks at a number of inputs to figure out how to respond, mainly the vac from engine and output shaft speed. You'll be changing both of these, so you'll have to retest. Also, you said you received the downshift by activating the kickdown, but not at WOT. You may very well get a kickdown at 2500 or even 3000 rpm at WOT.

[53burb]

Thanks guys, I will try it again tonight & respond back...

[53burb]

I tried it at WOT on my way home from work yesterday. No change. I will try it again after I do the rearend and tire swap...Thanks for the help...Chris

[ac102nv]

Hey Chris,

If you take off from a stop in Drive and floor it, does the trans shift around 2800 RPM's then? If that's the case then your kickdown is working as I would expect and YES this is adjustable. You would need to modify the govenor to get a higher upshift at WOT. You can do it yourself or have a shop take a look. I purchased a B&M kit from summit for a few $$ that makes this easy and straight forward.

[53burb]

I will check it tonight. Which kit from B&M did you use?? A regular shift kit?? I would like the kickdown to be operational until about 2750-3000RPM. Is this possible?

[Green Machine]

Assuming that is a momentary contact starter switch, to emulate normal operation, you need to hold the switch in during the duration of the WOT, and ONLY during WOT, cause thats what is is, it's designed to tell the tranny when you go to WOT, to activate it at any other time during part throttle is not what it was designed for.

[53burb]

I am holding it down for quite a few seconds, basically until I am satisfied that it is not going to engage. I have done this at WOT and partial throttle.

[Green Machine]

Try this - from a dead stop in drive, do not push switch, floor it and tell us at what rpms it shifts to 2nd and what rpm it hits 3rd. Then do same thing from a dead stop, hold the switch down the whole time now until it hits 3rd, floor it and tell us what rpms it shifts at then, that will help tell the rest of the story....

[ac102nv]

Greenmachine is right...I failed to mention, you should be holding the switch down, not releasing it. This will tell the whole story. Once you know that the kit I used to modify the trans was a B&M - 20248. You can search on Summit's website for BMM-20248, runs just under $30. Nice part is it comes with decent instructions to get what you want.

[76bonanza]

Do you have to drain the tranny to install and after install can you adjust it with out draining tranny again?

[ac102nv]

Originally Posted by 76bonanza

Do you have to drain the tranny to install and after install can you adjust it with out draining tranny again?

You actually remove the gov from the trans and modify it with this kit. And each time you make changes you have to remove. But there's no need to drain the trans. The gov is behind a little cover plate on the passenger side of trans just before the tailshaft, held on by 4 bolts on the TH400. If I remember correctly I jacked up the pass side of truck a little so-that no/very little fluid was lost during changes.

[53burb]

Sorry it's been awhile, but anyways, in normal driving, the trans shifts from 1st-2nd from 1500-1600RPM & 2nd-3rd from 1700-1900RPM. At WOT it shifts into 2nd at about 3400-3500RPM & into 3rd at about 3500-3600RPM, this is W/O the switch being pushed at all. So, do want me to try this same test with the switch being pushed the whole time from a dead stop at WOT???

[ac102nv]

Originally Posted by 53burb

... So, do want me to try this same test with the switch being pushed the whole time from a dead stop at WOT???

Yes exactly. The RPM's should raise, how much I'm not possitive. So far though it sounds like everything is working normally.

[stueber68]

I hace the factory kickdown switch that goes on the firewall if you need it. You can have it, just pay the postage. The trick will be getting the bolt on the pedal. Let me know. I can even get you pics if you need them.

[53burb]

When I stomp on it at WOT from a dead stop with the button pushed it shifts from 1st-2nd @4300-4500RPM & 2nd-3rd @3700-3900RPM. If this is normal, do you think that governor kit you bought will enable the kickdown to be actuated at 2000+RPM??

Stueber68, please send me pics of the switch. Right now, I have a rod-type mechanical linkage, but I will be switching to a cable-operated one shortly.

[ac102nv]

Those numbers sound like everything is working as it should. The kit I have is primarily used to adjust the upshift point at WOT. However, when you raise the upshift point typically the max rpm that it will kickdown at raises also. Not sure if I worded that right, but the higher the upshift the higher the RPM which it will still kickdown. Becasue of this I have mine set to upshift at approx 5k which gets me the kickdown rpm I want. When I want to run up to my max rpm of 6200 I shift manually.
To answer your question about the kit getting you the numbers you want is very tough. I would say most likely you'll be fine.