I was wondering if the N.O. 4th gear pressure switch P/N 8642473 in the homemade DIY kit is different from the one in my 1988 700R4 Trans? I jut got my motor and trans put in sat and I am going to start wiring it. Any help would be great thanks

 

I have the vac switch and pigtail and a lighted switch for this if you need it.
Both brand new the switch is GM in the box I was going to do this and decided to go to th400 instead. not sure what I paid but $25 shipped for those. The switch in the tranny is probably different I replaced mine I wish I could find the post on this.

 

Your 4th gear switch might be N.C.

 

you can use a dmm to check. disconnect the wire to the 4th switch. set the meter to ohms. if normally open when checking from where the wire connects to the valve body there should be no continuity. example like they aren't touching. this type of normally open provides a ground circuit to the system when pressure hits the switch and makes a ground. If you have a 2 wire tcc solenoid you can connect the black to the switch and run the one red wire to the left front(drivers front) pin of the tcc. this will allow lockup only when the trans is in fourth gear and power is supplied to the red wire. Wiring stock is recommended always when possible but who keeps things stock anyways. note:you can also use a th400 connector on the trans case it will fit and uses only one pin to simplify wiring. just hook the red to the single pin and you're done!

 

Right on thanks for the info..

 

I came across this info and was wondering if anyones done it this way?

 

that's a cool schematic. I haven't used all the things mentioned but checked it out electrically and found it to be accurate. I am planning a 700r4 build and saved it for future--thanks. I really like the part where you can switch off the tcc etirely with the 3 position switch. Lockup in low gears probably not needed but I have heard 4wd's using a low stall and lockup in low for engine braking down steep hills but i've never experienced. I have experienced front wheel drives with stuck on tcc sols. and they will kill the engine if you try to come to a stop when hot. ON THE DIAGRAM; pin is different letter on aldl and computer so use caution when wiring. one was a ground provided by computer and other was a power-don't add a power to a computer ground or poofffff. Also the two switches didn't apply to this application because in diagram says 2004r. Good stuff-I must try before I die.

 

Cool I am glad it might help some people. I am wondering if I got the wrong swith since my # pattern is different. looking at it on the left it goes 1,2,3 down and the right goes 4,5,6 down. will this work ?

 

If it's a center-off DPDT switch, it'll work.

 

it'll work center off, just to make it easier to wire change the #'s yourself on the switch so it's less complicated. #1 will stay the same. #2 would be #3, #3 would be #5,#4 would be#2,#5would be#4,#6would stay the same. no confusion if you change the #'s ahead of time. KISS THEORY: keep it simple stupid-works best when I do things.