TH 400 Install

[Kadzban]

Hello 6.2 Fans,

I'm finally redoning my truck after being down for about 1 year now and my question is what all is involved in running a th400 behind a 6.2?

I had a manual tranny and got a good deal on a th 400 from a 6.2 with a 205 tcase and driveshafts so I figure I'll go ahead and give it a try. The injection pump I'm running has a switch on the RH side I am pretty sure is for this tranny. It has 2 wires and both are cut where do these go ??? I'm figuring one goes to B+ and the other to a vacuum solenoid that tells the tranny when to kick down. And this solenoid must go between the vacuum pump and the trannys vacuum thing. Correct???

Also what is the electrical connector on this tranny for?

I also have the th400 flywheel, shifter and linkage so those bases are covered.

Let me know if you 6.2 fans have any info!
Or sources for info

Thank You
Jared Kadzban
83 6.2 diesel in progress

[NH2112]

Kickdown is handled by a microswitch behind the accelerator, which is mounted similarly to the stoplight switch. I think you generally want it adjusted so it kicks down at about 2/3 throttle. The switch on your IP sounds like a TPS for a 700R4, the TH400 has a vacuum regulator valve (but no solenoid) that varies vacuum based on throttle shaft positioning.

The electrical connector is either a neutral start switch or a backup light switch. You should have both, and I don't think both jobs were handled with 1 switch.

[Kadzban]

Is the kickdown switch then hooked to this vacuum regulator valve(VRV)? Then is the VRV plumbed in series with the vacuum pump and vacuum modulator on the tranny? Where is the VRV mounted?

I did some checking and it looks like on these truck there is one switch in the steering column that controls the reverse lights and neutral safety start.

But maybe the eletrical conector on the LH side of the tranny is neutral also??

Thank You,
Jared Kadzban

[Robyn]

Ok first off
HI there
You need the 6.2 TH 400 flex plate
The cast aluminum lower cover
The stabilizer bars that go from the motor mounts to the lower cover
(this stops the tranny case from breaking if you get wild)
There is also a large steel bar that goes from the right side rear of the t case to the right side middle bolt on the tranny bell, this stops linear flexing of the tranny and t case.
Now the controls, you will need the column shifter or some other means to control the tranny.
The single electrical plug on the tranny goes to a switch that is activated by flooring the throttle. The switch is connected to 12V and is normally open,
You can get one at a bone yard or the parts store, (Kick down switch) Its used on the 400 only.
The 400 is a vacuum modulated tranny and you need to get the vacuum switch to control it. This switch has two ports on it one goes to vacuum and the other goes to the modulator on the right front of the tranny.
The switch bolts to the IP where your little electrical switch is now bolted.
Make sure your engines vacuum pump is working good (26 inches at idle and steady) Install a vacuum storage can as it helps make things work better.
The switch will need to be adjusted so the tranny shifts correctly. Too much vacuum too long and it will shift late and hard. Too little and it will shift soft and quick. If you dont have access to the factory manual for the specs on setting the switch you can start with the switch installed with the bolts in the middle of the slots and go from there.
Looking at the switch from the passenger side, turning the switch clockwise will make the shifts later and firmer.
Be sure you fuse the kickdown supply wire.
You may run into drive line issues but factory shafts can be found easily as this was a common setup. Oh the wires on the switch you spoke of are of no concern, take the switch off and toss it on the shelf. The connector on the tranny is only the kickdown. Neutral safety is on the top of the column and usually in the same switch as the backup lights. Kickdown mounts on the throttle pedal braket and the switch usually has a peg that goes through the long slot in the bracket.
Fairly straight forward. You may have to improvise to make it work right.
If your truck has/had the clutch switch that required the clutch be depressed to start use these wires and run them through the neutral switch to get the safety factor needed.
The kickdown is a no brainer, grab a 12v source that is switched (IGN) and be sure its fused and run it through the kickdown switch and on to the tranny single spade.
Lets see now HMMMMMMMMMMM Motor mounts are the same, tranny rear mount and cross membershould be ok too as the t case sits in the same spot.
Good luck and keep us posted

Robyn

[Kadzban]

Thanks for all the great info I got an 86 K30 no engine that I took parts off of so I have pretty much everything except for one of the struts, the vacuum regulator valve that mounts on the IP, and I think I need the head that mounts on the oil pump drive my truck didn't have a vacuum pump. I hope I can find these parts. Peninsular diesel is right in town I think I can get the pump from them.

Thanks again!
The truck is getting painted in Novemeber so hopefully By 2007 it'll be running.

Jared Kadzban
83 6.2 diesel in progress

[Robyn]

Sounds like you are set to go.
Good luck and keep us posted
best to ya
Robyn

[Kadzban]

Well I got together all the parts I need for my tranny swap. The Vacuum pressure regulator (VPR) I got has a kick down built into it so that should be easy. My question know is when looking in my service manual to set up the VPR it says to apply a source to the lower fitting and a guage to the other then pump it to 20 rotate throttle to guage block and adjust VPR to 8 on the guage.

Well when I pump up the VPR with my mityvac on the lower port and with a gauge hooked to the top port pressure bleeds off. I just kept pumping the mityvac to keep it at 20 and set it per manual. Is this normal to lose pressure through the VPR? or can I fix or do I need a new VPR. Or should I wait until I get it running and go from there?

Thank You,
Jared Kadzban