Turbo 400 Build - Mega Carnage to Better than New.

[HotRodPC]

I don't think you read my post correctly, I know all about the manual valve body stuff, I was wondering about adding the kickdown feature. My truck doesn't have the kickdown harness, is there a place I can get one new one and the switch?

Ohhhh OK. There are some places that have it aftermarket. I think your current gas pedal bracket will support the switch, and there isn't much to the harness. If your pedal doesn't support the switch, then just get a Th400 pedal bracket from a PAP. Pretty much, 1 wire from the switch to the spade on the outside of the case. You could probably make your own, with a 5ft - 6ft length of wire and 2 spades that can be solderless connectors since it's not a vital critical component.

 

[J Knight]

Yea I have the bracket in your pic just not the switch or harness. I would realy like the harness for the oem style plugs instead of a home made one. I guess I could find it through summit.

 

[HotRodPC]

Yea I have the bracket in your pic just not the switch or harness. I would realy like the harness for the oem style plugs instead of a home made one. I guess I could find it through summit.

Get a switch, and run a single wire. That easy. I think you get ing power to the switch from the fuse box, then one wire goes to the solenoid spade on the trans. EZ PZ !!! I'd give you a switch offf the burnt truck but I have a feeling it's burnt up. The firewall got way to hot. The pedal bracket is probably good though.

 

[SlickGTP]

Yea I have the bracket in your pic just not the switch or harness. I would realy like the harness for the oem style plugs instead of a home made one. I guess I could find it through summit.

What's your timeframe for this? I need to hit up the yard sometime in the near future to get some electric lock and window harnesses for my doors and I can walk out with that harness intertwined with the stuff I need for nothing extra.

What's two wires extra in the mix of two other harnesses...

 

[J Knight]

What's your timeframe for this? I need to hit up the yard sometime in the near future to get some electric lock and window harnesses for my doors and I can walk out with that harness intertwined with the stuff I need for nothing extra.

What's two wires extra in the mix of two other harnesses...

Not in a rush. I dont even have heads for the motor yet.

 

[SlickGTP]

Hey HR,

How do you know when a reaction carrier is toast? Here's the one I pulled out of the spare TH-400.

You must be registered for see images

The ripples might come off with a bit of work with an emery cloth, but not sure if it's worth the effort. Also, is the output carrier supposed to be colored like that? Thanks!

 

[HotRodPC]

Ehhhhhhh, Being that is the easy to find one, I'd probably replace it. But, if you notice how big the Servo is that operates that band, and how much meat is on that band, and how wide that band is, you can sure get by with using that drum on a Th400. Unlike the 700r4 2-4 band. that is narrow, very thin layer of friction of material and the servo size.

But, being that is a very easy to find and replace part, I'd probably replace it for just because and that one is a tad excessive. Now if it were the illusive dog bone wedge sprag drum instead of the roller bearings type, I'd use it for sure but I'd do my best to smooth it out first. That's the most important part of that piece. The roller clutch/sprag.

 

[SlickGTP]

Cool... As it's really just a spare part at this point I won't worry about it too much. It does seem like it's seized on the output carrier though. The two parts don't want to come apart very easily.

 

[HotRodPC]

You can tell by the color that that sun gear in the back, it got hot back there in the back of the case. Real Hot !!! See the colors.


And maybe not. That's not to bad. Could have gotten that hot during machining when made too. That one isn't to bad.

 

[SlickGTP]

Yeah, I was wondering if it got hot in the case or if that was a manufacturing side-effect. The Reaction Carrier won't spin at all which locked the first set of planetaries in place. I'll have to give it a bit of persuasion this evening and see if I can get the two apart.

 

[SlickGTP]

Hey JKnight

I finally got under the dash and took a few photos of the th400 kickdown harness. It's going to be a little different than later models, but mostly just wire color I think.

You must be registered for see images

You must be registered for see images

All it is, is two wires taped together... The Brwn/Wht wire goes to a fused accessory port on the block and the orange wire goes to the transmission. If you don't care about the clips on the end then we can make you one easy enough. If you want a more authentic looking one I'm sure we can hack one together from misc parts acquired from the junk yard.

 

[HotRodPC]

Jep, That's all there is to it.

 

[86ClassicMan454]

Hot rod I have read some replies that you have left on other forums and you seem very knowledgeable. I have a couple questions and would really appreciate your help.. Ok so I jus purchased a gmc2500 454 with a 400 trans, one of the trans lines are leaking... It has been stripped and I haven't been able to get it off. Any advice?
Also it is shifting really hard, smoking white or grey a little bit, and now it is starting running a little bit and dying out.. Oil pressure is fluctuating a lot. When I go 40mph and over it stays right around 40psi but at a stop light it's dropping down to 30-40.. I jus purchased this truck a couple days ago don't know much about it except it's in really good condition aside from what I have mentioned...

 

[HotRodPC]

As far as hard shifting and smoking gray and white, it could be a blown vac modulator. You're possibly sucking some trans fluid into the intake via the vac line to the modulator which will also cause a bit late and harder shifts.

As far as the the line leaking, luckily the brass couplers are threaded into the case. You can replace those from another unit if you can find one. It's uncommon for those to leak for any good reason other than someone in the past had the threads cross threaded when hooking the cooling lines up.

 

[HotRodPC]

Very cool to be seeing likes on this 10 year old thread. Hard to believe it's been that long ago. Unreal how fast time flies.