A518 won't shift into overdrive

[69wacuda]

Hey guys, a little help needed.

First off I installed my 518 behind my 360 using a automatic OD engage kit from Performance transmission center. It worked for about three days and now my OD won't kick in. The tranny is a rebuilt one with less than 250 miles on it. The kit I purchased cam with a vacum switch, two oil pressure switches (one for OD, one for lockup). Does anyone know of a way to test to see if the switches went bad or if it's the tranny? The tranny shop I bought the trans from is 80 miles away and I don't want to haul it until I have checked everything.

Your help is appreciated!
Grant

 

[67Dart273]

Well, start by posting a wiring diagram.

You mean, this?

http://www.transmissioncenter.net/SwapInformation.htm

http://www.transmissioncenter.net/img3.jpg


Even though somewhat cobbled up, this is a fairly simple wiring problem of several switches, so either the "system" is not getting power, or the wiring has a problem, or one of the switches is bad, OR worst case, the transmission has a problem

You should be able to bypass the switches one at a time with clip leads, etc, or even run temporary wiring to get power to the trans itself to see if it will engage.

What you are doing is running POWER to the center terminal of the connector, and the vacuum switch switches this power ON to the OD when the vacuum is HIGH, BUT the OD does not turn on until the oil pressure switch on the transmission "makes." So BOTH switches must close to turn it on.

So if you bypass BOTH switches, the OD should be ON.

If it is not, you have either a power supply problem, a wiring problem, or a bad connection at the transmission, or an internal transmission problem

So get right down to the transmission and check that you are getting power to the connector with the switches bypassed, OR

get a spare connector and hook temporary wiring to it so you can hook it to 12V for testing.

 

[69wacuda]

I installed a toggle switch and can feel the converter lock up when I flip it, so power is getting down there. This should mean that either the OD pressure switch is bad or something in the tranny is, correct?

 

[whitey]

Funny,
I just did this swap and I used their kit, but the OD woud not kick in. I put a light in the ground circuit with the rocker switch so when the pressure switch grounded the light would kick in. So I started checking everything first the fuse I put in from power source to relay...good, relay contacts closed and power went to the vacuum switch.

With car turned off (NO VACUUM being pulled) and using a test light the connector marked NO had power coming out and going to the trans. THe connector marked NC didn't. Started the car and pulled the throttle a bit I used the test light again, this time, the connector marked NO had no power and the one marked NC had power.

THe vacuum switch was assembled wrong, had to put the wire leading to the connector on the case on the NC connector.