uriahpick

I did the "Controlling OD using governor pressure" fix, but it isn't working. I spliced a wire into the smaller (non-blue) wire coming from the overdrive solenoid (I think it has a green or orange tracer on it). The set up isn't working and in troubleshooting it, I got some puzzling results. With a voltmeter, I tested my switch and whether it is actually creating a ground when ON. When the switch is flipped on, that side of the A/C pressure switch installed in the tranny is grounded.....when flipped off, that side is no longer grounded (so it is working from the switch back). The problem I came across is this: the wire I tapped into the overdrive solenoid wire is showing constant ground, as if the wire from the overdrive solenoid is already grounded. I am assuming that it should not be, or the O/D would always be on.... I also hooked the spliced wire directly to the switch (bypassing the pressure switch that I put in the transmission port) and I still have no overdrive. So I know that manually grounding that wire is not providing overdrive. Could the solenoid have gone out, and if so, is it replaceable (it looks like it would be a booger to get out)? Or could this be an internal transmission problem with the overdrive unit itself? If so, what are my options? Thanks for any help...just trying to figure out where to go from here.

uriahpick

Did a little more research and realize I need to drop the pan and possibly remove the valve body (hope not) to change out the solenoid....also, I saw that overdrive is just the high range of 3rd gear. Does this mean that if I have 3rd gear (which I do), then it is mechanically sound? I recently had the pan off to change the filter....am starting to wonder if I might have caused this problem myself. Thanks guys for any info.

JD730

Have you ever had Overdrive?
When you check the connector, 1 wire has +12 volts when the key is in the run position and the other goes to the PCM (this is the 1 that gets grounded to activate the solenoid). The colors escape me at the moment. I'd eliminate all the extra stuff and just run a wire into the cab with a switch to ground it to check and make sure OD works first and then wire in your fancy stuff.

Then you can go about determining if the solenoid is shot or the OD clutches are toast.

wannadiesel

The power wire is dark blue. If the solenoid and OD are OK, if you have 12 volts at the blue wire and the other wire is always grounded, the truck will drop into OD as soon as it shifts to 3rd.

BC847

This may help. Dunno for sure.

Go here ~ http://www.transmissioncenter.net/dodge.htm

And scroll on down to almost the bottom looking for "Dodge 518 Conversion"

It shows how to wire that and a lock-up converter if need be . . . .. I think.

Hope this does help.

uriahpick

I presently have a ground wire running straight to a switch in the cab from the "non-blue" wire going to the overdrive solenoid. I still don't have overdrive, so I am hoping it is just the solenoid gone bad. I did have overdrive before, but have not had it since my last fluid/filter change and then flush. My fluid before changing was very dark....burnt. I had been pulling some heavy loads recently and my fluid deteriated pretty quickly. The filter was also completely stopped up, and the truck actually left me stranded (transmission wouldn't pull). But when I dropped the pan there were no metal shavings, very little clutch material....after the flush and filter change, it is running like a dream, shifting flawlessly....except no overdrive now, and I had it before. Am thinking that the heat from previously mentioned episode might have effected the overdrive solenoid.....at least am hoping that is all.

Boatnik

The port in the solenoid is quite small. It doesn't take a lot to clog. When you drop the pan and filter, you will be looking at the solenoid. Be real careful with the wires. I accidentally pinched and grounded mine installing the filter. It shifted into overdrive as soon as it went to third. The new solenoids come with a tie wrap holding the wire to the solenoid bracket. Get rid of it and route the wire away from the filter. That is what we did to remedy the problem. Before you go through all that check the plug going into the tranny. You may have a loose connection.