Need help with my 700r4 TTC wiring harness

[Ricko1966]

Hook your low vacuum switch up it will make the truck more drivable without it your converter will lock going into 2 or 3rd depending on the transmission. With it working the converter won't lock until you are done accelerating through the gears,and won't be as harsh of shifts.

 

[jh86]

Found this with great info too

Need help diagnosing 700R4 lockup issues.. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Need help diagnosing 700R4 lockup issues.. The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

67-72chevytrucks.com

 

[Jgonick]

The EGR connection is optional. Having it hooked up properly gives you lockup in 3rd gear, but you don't really need it.

This was my understanding also- I also don't have an EGR (wires are just tied up out of the way.) The wiring diagram you posted is how my K10 is.

Also just a side note- -there are several ways 700R4 are wired internally and externally depending the vehicle setup.
ECM, Calf or Fed or Alt etc... Just pointing this out, because if a PO swapped or rebuilt the transmission you really do not know what is going on without opening and looking inside transmission.

 

[Matt69olds]

This is the method I used to wire the TCC on my 81 GMC. The only difference, I used a time delay relay I bought from Amazon. It was about 15 bucks, and has a 10 second delay.

https://www.hotrod.com/how-to/hot-rod-rescue-lockup-700-r4-torque-converter-without-computer/

If you use a standard relay, as soon as the trans shifts to 4th gear, the converter will instantly lock. If you touch the brakes, the converter will unlock, and assuming the trans is still in 4th gear, it will immediately lock again. Using a time delay relay gets rid of the jerky/clangy lockup.

It’s about as close to a factory feeling setup as possible, and pretty cheap.

 

[Jgonick]

Just posting this if someone is curious. This is the wiring diagram (like the original posted in post #3-without EGR bleed.)

 

[Jgonick]

4wd have the unobtainium 4wd relay setup that disables lockup when in 4wd

I meant to mention this earlier- I found a relay that will work - Relay RY31 around $20 at Oreilly or other part stores

 

[BigSW]

This has been very helpful. I hope this is my last question but how would I wire in a light for the TTC (using the EGR diagram)??? Thanks everyone!

 

[Ricko1966]

This has been very helpful. I hope this is my last question but how would I wire in a light for the TTC (using the EGR diagram)??? Thanks everyone!

Why do you want to? The only way I can think of to wire it your light would light when power was applied to the tcc solenoid.But that would only tell you power was being applied,not that it was actually working.Verifying it is working is more important to me than seeing it has power.

 

[BigSW]

Why do you want to? The only way I can think of to wire it your light would light when power was applied to the tcc solenoid.But that would only tell you power was being applied,not that it was actually working.Verifying it is working is more important to me than seeing it has power.

Yes I see what you mean I thought there was a way to wire one so that it would verify that it was working. Not when power was applied. Maybe not…