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Discussion Starter #1
I searched and found nothing on 3rd & 4th lock-up, only 4th gear lock. Maybee someone can help me with this. I have a 86 700R4 that was rebuilt before and they hacked up the wiring so there was no lock-up. The last rebuild only lasted 10,000 miles! This is going into an 86 truck that will do some towing, so really my question is should it lock in 3rd gear as well as 4th? Most towing is done in 3rd gear, not in overdrive. If ther is no lock-up in 3rd will the tranny overheat while towing a load in 3rd? Thanks!
 

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>so really my question is should it lock in 3rd gear as well as >4th?

Normally no. Lock up is initiated by the high gear pressure switch in the valve body. When the trans shifts to 4th, line pressure closes the switch and energizes the lock up solenoid. You can, however, override the lock up function. Applying 12 volts to the solenoid via a manually operated switch will initiate lock up in any gear. You should wire it through the brake light switch so that it unlocks when you apply the brakes, and then to the manual switch. You'll have to turn it off manually too. There may be other ways to achieve lock up in other than 4th but I'm not familiar with them.

Bob
 

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in the early daze of the 700 tranny GM locked the converter in 2 , 3 & 4th gears.

Some 1986 units had a two wire solenoid and both wires were hooked to the case connector . The computer controlled all lock/up functions.

IF your L/up solenoid is the original unit , there may be a number stamped into it.... IE: 4123 , 4126. This would help match up what may have been the OE solenoid setup on your vehicle
 

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Discussion Starter #4
Well the original solenoid is gone to the trash, but it was a 1 wire unit. The valve body has plugs in a the ports where the switches normally go. Crosley, I think at one time I was on your geocities page and there was a wiring diagram for 3rd and 4th lock-up, but it has since be removed to avoid confusion. Do you still have those other diagrams or can you explain how to do this?
 

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chrisape said:
Well the original solenoid is gone to the trash, but it was a 1 wire unit. The valve body has plugs in a the ports where the switches normally go. Crosley, I think at one time I was on your geocities page and there was a wiring diagram for 3rd and 4th lock-up, but it has since be removed to avoid confusion. Do you still have those other diagrams or can you explain how to do this?

My pages never diagrammed a 3rd & 4th gear lockup.

I had something different on the pages....... I deleted it since email was rampant from people that could not understand the information on the page.


IF your v-body ports are all plugged from the factory , I would guess you need the dual wire solenoid with the red positive wire at "A" position in the case connector with the black ground wire in the "D" position.


"A" position on the case connector is front outer hole........ "D" is directly behind "A".

I recall seeing this wire harness on many 86 model 700-r4 trans , no pressure switches on the v-body.

Not sure if this helps or confuses you


:D
 

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700

easy way to have lock up , depending on your year of 700.
but with 86 this should work you may not be happy with the results, lockup after 2nd and stays in lock up there after in 3rd and 4th. drop the pan install ck ball inside lockup solenoid neck. there have many posts on this subject and many ways to fix it
 
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