700R4 Lockup Wiring Options

[jc74868]

I'm not a very technical guy, but I have always done my own work and can make things run. But there are lot of things I just don't know.

Here's my issue:

in 2002, I put in a hopped up 350 & 700R4 in place of the old 350/350 in my '78 SWB Silverado.  I had to have my driveshaft modified, rear trans. mount adapted and I grabbed the lockup wiring out of the donor vehicle (an 85, I think, non computer Suburban) (wires coming from trans to a little vacuum thing, then and hooked it up all up w/the switch on the brake pedal etc... )Everything seemed to work fine (as far as I know...I honestly don't even really know what the whole "lockup" thing means...I do know I got way better gas mileage and less RPMs cruising down the highway)

Now, after letting my truck sit for the past few years and waste away, I'm hoarding parts for another go at it. I have 383 I'm ready to put in and I need to do something about the leaky old,  abused,  700R4 behind it. I could probably just put new seals in it and go (and replace the lockout wiring the rats ate), but I want to start fresh again.

What do you guys think? Pull it out and have it rebuilt and hook it all up like I had it? OR, buy one of these performance units I've been seeing that have the 1 wire lockup mod.

I'm aware of several great builders who do these and it almost seems easier for me to order one of these and slap it in, and hook up the 1 wire...unless that would result in a weird driveability issue compared to going back with almost factory style setup I had.

I have no idea how the two would compare and the 1 wire thing really works.

I guess I just like the idea of getting a spanking new nicely built 700r4 and slapping it in compared to taking mine out, hauling it to a guy a 100 miles away,waiting and going back to get it whenever...the cost between doing either is not that much different.

Just won't to make sure I'm not shooting myself in the foot buying a 1 wire when having mine rebuilt might be the best scenario

[VileZambonie]

Here is an example of some DIY method's http://forum.73-87chevytrucks.com/smforum/index.php?topic=7310.msg42965#msg42965

You can choose whatever method works best for you. For me I want the converter to unlock quickly when I accelerate, when engine load increases, when I hit the brakes and at the appropriate time when governor pressure is high. This is why i drew up this diagram to help guys figure out a manual way to do it without a computer. You can simply use the pressure switch method first but if you want to further curtail it or manual override, use any variation of the drawing.

[chevn-up]

Been working on this same thing. I am going with a 5-pin relay, as well as the brake pedal disconnect to control on/off. It's the one wire system, controlled from the NO pressure switch at the tranny that you spoke of. Will be using a toggle, as I don't forsee using the lock-up for anything but the highways and interstates. Mine is a 350C. I've owned the truck since 2007, and I never knew I had this. My new tach will show if it works. Good luck.

[jc74868]

I'm still on the fence about what to do. I've been thinking about the the Revenger 700R4 from Animal Performance. It has a wire lockup. It states that you just hook it up to a 12V fused key-on source (toggle is optional)...really not sure how that whole thing would work.

It also has a constant pressure valve body so that TV cable is only used to set shift points and there is not risk of burning up the trans from TV cable issues.

This trans builder has stellar reviews, but when I asked a question about the 1 wire hookup, he pretty much just quoted what the website already stated "4th Gear Internal Lockup 1 wire Design no lockup kit needed just supply 12 volt key on source and away you go !"

[chevn-up]

Yep. The one-wire is how the engineers designed the system, with the inclusion of the vacuum switch. As VileZ. stated, upon quick acceleration, the switch unlocks the converter. Seems to me the only draw-back (with the vac. switch) is the erratic locking/unlocking, you know, when the vehicle is at the "shift point". But, without it, you lose that performance.

[bd]

Seems to me the only draw-back (with the vac. switch) is the erratic locking/unlocking, you know, when the vehicle is at the "shift point".

The nuisance hunting (cyclic disengagement/engagement) of the TCC is greatly decreased and managed by insertion of a vacuum delay valve between the vacuum source and vacuum switch.