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Lets talk 700r4's for a minute

Vombrown

Vombrown

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so my donor vehicle has a 700r4 behind the 6.2 diesel (1984). My understanding is this version has the full hydraulic shifting and an electronic lockup. I am not up on my transmissions stuff but this has the tv cable on the right rear block above the valve cover.

I am looking to delete anything on this engine that is electronic. Basically anything that isn't absolutely needed is going away. What I want to know is this. What does the throttle position sensor on the injection pump control? Tv cable is a manual control, so it stays. I will control the lockup torque converter with a switch and a brake switch from the truck so what other input does the transmission need?
 
I don't think there was anything electronic on an 84 700r4. There's not on my 86 gasser.
There is an electrical circuit for the torque convertor lockup control. The diesel uses the TPS because it doesn't use the vacuum switch like a gasser does. (no vacuum). I believe Transgo has a full hydraulic replacement kit for that.
 
Before you go getting all gung ho on this 700R4, you need to make sure your dana 20 is 27 spline, it does not look like it from the pic in your other thread. You might end up getting a 400 instead, especially if you want the power you are looking for out of your 6.2.
 
Vombrown said:
What does the throttle position sensor on the injection pump control?
Click to expand...
That's a Throttle Position Switch. It read 0 or 5V, which is very different from the sensor used on later models that reads between 0 and 5V to detect a precise throttle position. That level of precision is required for a 4L60/80E, and is super handy for boost and throttle referenced accessories like meth injection and nitrous. The factory TP switch was used to manage vacuum for, among other things, EGR controls in 1/2 ton trucks. It doesn't connect to your 700R4.

The torque converter lockup is actuated electrically, so a simple 12V power interrupt will let you control that. The TV cable controls line pressure.

I went through several 700R4s behind my all-mechanical 6.2TD until finally installing and wiring a 4L80E, and I've never looked back.

David
 
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Justin V said:
Before you go getting all gung ho on this 700R4, you need to make sure your dana 20 is 27 spline, it does not look like it from the pic in your other thread. You might end up getting a 400 instead, especially if you want the power you are looking for out of your 6.2.
Click to expand...
The Dana 20 is a 32 spline. Simple output shaft change for the 700 to use it. What I thought was a GM Dana 20 is just a jeep version with an aftermarket adapter.
 
AgDieseler said:
That's a Throttle Position Switch. It read 0 or 5V, which is very different from the sensor used on later models that reads between 0 and 5V to detect a precise throttle position. That level of precision is required for a 4L60/80E, and is super handy for boost and throttle referenced accessories like meth injection and nitrous. The factory TP switch was used to manage vacuum for, among other things, EGR controls in 1/2 ton trucks. It doesn't connect to your 700R4.

The torque converter lockup is actuated electrically, so a simple 12V power interrupt will let you control that. The TV cable controls line pressure.

I went through several 700R4s behind my all-mechanical 6.2TD until finally installing and wiring a 4L80E, and I've never looked back.

David
Click to expand...


This is what I was thinking but all my factory manuals are in a box in the attic somewhere. I couldn't remember what it's actual function was in this application.
 
That tps inputs throttle position to the ecm (it does have one..above the glove box) Seems like cold advance also comes from that ecm.
 
Keep the factory lockup setup. There are no electronics, just some switches and it will work better than an aftermarket kit. Flipping a switch manually is uneccesarry annoyance. Plus, why spend time and money to downgrade?

Having said that, you will never have full manual control of the TCC. Even if you drop the pan and bypass the switches, you still only have hydraulic pressure to the solenoid under certain conditions. So it would keep you from certain bonehead mistakes like stalling the engine by keeping it locked in 1st gear. Still, you want it to unlock when accelerating, when on the brake and when downshiftig and you would lose some of that.
 
I will be using a stripped down version of the 84 wiring harness for the truck to upgrade the fuse block. No proble to keep the components to control lockup. I'm about to pull the engine out of the donor to break everything down. I haven't deleted anything as of yet.
 
Does any One have a 700r4 sitting on the floor that they could measure the protrusion of the output shaft from the rear of the adapter. Preferably from a 208 transfer case.
 
Can someone actually post a diagram of the electrical switches for a 700r4 behind a 6.2L I have one and a paint and body idiot tried to rewire everything.
 
here ya go

full
 
Just so it's out there, spoke with advance adapters tech department today trying to salvage a 700/Dana 20 combo. They said their engineers are working on a 27 spline input to 32 spline outpuT spud shaft right now that will be a future part of their adapters. This will make adapting any 27 spline output transmission to any 32 spline input transfer case possible without removing the output shaft of the transmission. Pretty cool
 
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