Hi folks, If this has been addressed here or elsewhere on the internet I haven't been able to find it yet. This has confused me and my opinion about what is happening has changed over time.

When my friend got the car a bit over a month ago the PO told us that it had recently lost 4th gear. His family had upgraded to a newer vehicle so rather than look into the repair they let this one go for a steal. He told me a thing or two he'd looked up about the O/D solenoid and I assumed I needed to clear the passages or replace the relay. After a couple flushes of the brown fluid however to my delight I regained fourth. I was all excited until I realized the button wouldn't let me shift down into 3rd like it should and also didn't illuminate the "up" arrow on the dash. I climbed back under the car and started tracing wires to discover there is no connection at all between the relay and the solenoid, the wires disintegrated.

So now I'm confused. There is nothing energizing the solenoid, but it appears to be functioning in the energized position, up, to allow flow to 4th. I haven't separated it from the transmission yet, but it does seem to be the original by the3 corrosion and is not a bypass plate like the ones carried by IPD. Once I get the chance I plan to get a new solenoid, switch, and relay off a parts car. In the meantime I don't want to lose fourth again so I'm not planning to reconnect power to the solenoid. My hypothesis currently is that either: A; The solenoid seized in the energized position due to the crappy fluid that used to be in the tranny. B:The O-rings inside disintegrated, allowing pressure through. or C, both. Should I be concerned the new Dex III, Dex VI blend in the tranny is cleaning up the jammed solenoid and that at some point it will click down into 3rd and not open back up until I swap parts or at least re-wire it?

Also I've been thinking about installing an on off switch on the dash to entirely bypass the relay whenever I get a new solenoid ,hoping to mitigate circuitry issues and to get the switch off the shift lever entirely. Also, to confirm, will I find the AW-70 in 740s and 940s as well?

any and all advise is appreciated. Back to Craigslist now to find snow tires for it.

 

It is strange that it is shifting into 4th and then OD without the wire to the solenoid attached. As to the solenoid you can get new ones on ebay for $30-$60 each. There are 2 o-rings with it and it is easy to remove/install. Just 2 bolts hold it on. It may be possible that dirt is holding the valve open but I kind of doubt it. I wouldn't buy one from a salvage car when you can get one on ebay .

 

Much appreciated, I'll take a look on ebay later.

Just to confirm and make sure I didn't misread, but on the AW70 auto trans 4th is overdrive correct? otherwise I have a whole new gear to discover!

 

It is a 4-speed automatic.

If you search the forums here, you will see that IPD sells a bypass plate that replaces the solenoid the essentially makes the transmission a permanent 4 speed with no way of disabling 4th gear. They charge somewhere around $30 for the plate. Some folks here rather than pay for the plate use a dremel tool to modify their existing solenoid to make it work the same way.

Perhaps the previous owner rather than fix the solenoid modified it in this manner.

 

4th gear is the OD and you also can see/feel the torque convertor lock up when in 4th. The engine speed drops around 200rpm.