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700r 4 tcc sol wiring

4K views 5 replies 4 participants last post by  Crosley 
#1 ·
The 3-4 gears went out on my 88 gmc 8700 r 4. Fluid is burnt black. I installed a used tranny from the junk yard. The shift shaft bracket was different. I changed that to my origanal one. I pulled the pan to install a new filter and the wiring had been cut out. I double checked with the tranny I pulled out. The one pulled out has a white electrical plug on right side behind the TV cable. Inside it has one plug in switch and 2 round switched before the wiring ends up at the tcc sol. The newest installed has the white connector behind the TV cable but has 4 round switches. The last one sits over the tcc Sol. I do understand that my truck,88 GMC 1500 4x4 auto, comes with 2 motors and two trannys that are interchangable in any fashion. Can anyone give me any insight into this electrical part? I want to get a new one at the dealer but am unable to answer a lot of questions on the tranny. Any diagrams?

many thanks,
 
#2 ·
May be a Temp switch, the Round switches that screw into Valvebody are Pressure switches. Temp switch prevents TC Lockup at low temps and and some force Lockup at very high temps.
There are many different wiring Combos. You should be able to just make it match the wiring from your old Trans. May have to remove switches & plug a few ports. 1/8" NPT plugs.
Lots of good 700R4 wiring Info here >> http://www.rowand.net/Shop/Tech/LockupTCCWiring.htm
 
#4 ·
700 r 4 trans

I talked to a tranny expert here in Duluth and he said the transmission would run fine with no wiring harness. It is just an electrical connection to force lock up instead of fluid pressure. He said it will still lock up using fluid pressure. Sound crazy or real to anyone? I have not had the truck on the road with this transmission in it. I want to find out if it will run normal without the electrical connections.
 
#6 ·
jwwoodsman said:
I talked to a tranny expert here in Duluth and he said the transmission would run fine with no wiring harness. It is just an electrical connection to force lock up instead of fluid pressure. He said it will still lock up using fluid pressure. Sound crazy or real to anyone? I have not had the truck on the road with this transmission in it. I want to find out if it will run normal without the electrical connections.

Find a new trans person... In the late 1980's the fluid lock up assembly in the valve body was removed and aluminum plugs installed.. and later the whole passage was not machined in the valve body casting = completely gone.

if you do not have the correct valve body , the kit for hydraulic lock up of the converter clutch can not be used
 
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