700R4 installed!!

[sam's 72]

Well, I got the 700r4 in, and driving. I do not have a tach so I don't know how much RPM change I got out of doing this. So far so good, done took it on a 50 mile trip every thing seems good. The only thing I didn't have time to do, was go with a one piece drive shaft. I will do this next. Had my tranny guy set up the TV cable with gauges, and installed a 28000 gross vw, tranny cooler. The biggest thing I like so far is the lock up on it, it is set up to lock up hydrolicley. No wire involved to hook up to brake.
Sam

[72chevyLWB]

let me know how you did the lockup. I have a painless wiring and not sure if its working. And I wouldn't recommend 1pc driveshaft with a LWB.

[sam's 72]

72chevylwb,
The tranny guy built it this way, I am not sure how it is set up internally, for it to lock up hydrolicly, but he did it, say he does them like this for older cars and trucks all the time.
maybe someone on here that builds trannys can give you some insite on it.
Sam

[Project1970]

Lockup can be a b*tch sometimes...it depends on what your 700R4 is from.

It's supposed to be a simple matter...there's a 4-pin connector on the tranny, you only need two of the pins, I believe A and D. You should be able to just put D to ground and whenever you want it to lock up in 4th, give A 12 volts. The ideal way to do this is to run a wire from the fusebox, then to a brake switch that's normally closed (so that when you hit the brake, the circuit is open and the converter unlocks), then to a vacuum switch that's also normally closed (again, when you stand on it, it unlocks since it will also kick down to 3rd) and then down to A.

The transmission should be wired internally so that when it hits 4th gear, it closes a switch, it has 12V on A, and gives that 12V to the solenoid. This is how 700R4s were wired up from '87 until whenever the car it came from was converted to a computer setup - electronic speedometer drive is a good sign of this. (I had to go through this all the hard way - my tranny shop never told me it was set up like this. It was supposed to be a bolt-in for anything from '87-'92...yeah right).

These transmissions were wired to be installed with a computer - the 4th gear switch is normally -closed- and when it opens, it simply takes a signal away from the computer, which then hits the solenoid directly with 12V - I believe these are the only ones that are internally wired to use 3 of the 4 pins. The easiest way to wire this is just to replace the 4th gear switch with an early-style normally-open one and wire it like an early transmission.

The thing is, I don't think these were the only two wiring setups, and there's different styles of switches and solenoids - one wire solenoids, two wire solenoids, one wire switches, two wire switches, etc etc etc...it's a big mess, really, to describe. But if you're decent with circuits and a voltmeter (to see whether a switch is normally open or closed), you can do it no problem. In the end, you want a series circuit from the 12V fuse block to the n/c brake switch to the n/c vacuum switch to the n/o 4th gear switch to the solenoid to ground. So, under light throttle in 4th gear, it locks.

It's quite obvious when lockup works - you can let off of the throttle and your RPMs don't drop at all, really.

Did the above make any sense? LOL...