I finally discovered the Big Issue with the new to me 98 V70... an apparent PNP issue. After warming up, the transmission MIL goes on, the transmission mode lights flash and a few seconds later the car will slip into neutral. Oddly, killing the car and restarting it cures the problem for a very short while (like minutes) but then it starts up again. Sound like a classic PNP issue or something more serious?

Drain the fluid asap, add back about 3.5 quarts. The tranny has a non serviceable screen filter and if that gets blocked, the tranny is hosed.

If you had a scanner, you could check for codes when the MIL is flashing. One or more of the solenoids could be plugged.

Klaus
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1967 220 belonging to C.A. lives on

I drained the fluid from the car after letting it sit all weekend. Got about 3.5 quarts of very brown fluid out. I put back in two quarts and ran the engine for a few minutes, then drained it again. Filled it back up, then pulled the fluid cooler return hose off the transmission and alternated running the engine and filling the transmission back up. After about two total gallons of fluid, it was running pretty red and looking good. I put two quarts in and let it run for a minute or so - the malfunction light went out of it's own accord. I ran it through the gears a few times then shut it down. MIL stayed off, so that's an initial positive. Need some more ATF - it's still a quart or two low, but it's solid progress.

I can add some additional details:

1. Reverse lights seem to work properly
2. In playing with the PNP alignment, there is no adjustment I can make to turn the reverse lights off with the shifter in reverse... whether the PNP is all the way "left" or "right" the reverse lights stay on. I tightened it back down about in the middle of its adjustment range, haven't driven it since.
3. The shift interlock is permanently locked. I can use the override to shift gears. I had initially assumed the microswitch was the problem, but perhaps it's related to the PNP?

Soooo ronery in my own thread here...

Anyway, I took apart the PNP sensor yesterday to check out the guts and give it a cleaning. I found the contact furthest from the base of the arm was seriously worn, giving an uneven contact surface. I used a small file to flatten it back out, then pulled out the springs slightly to give them a little more spring. Cleaned it up, lubricated with a di-electric lubricant and put it back together.

I read some threads here about using the reverse lights to properly position the switch, but that seemed an imperfect method. Obviously the Volvo Special Tool is the ideal approach, but I don't own one. I figured the alignment process was actually supposed to align something, but what?

On inspection, it seemed pretty clear what the alignment tool was in fact aligning so I made the image below to help visualize it. I used a multimeter to "map" the contacts inside the switch with the connector pins, and found that in the proper position the "wiper" should be making contact on pins 6 and 7. Those contacts are pretty small, so the proper position isn't subject to a lot of adjustment - you can see that in the image. My photoshop isn't perfect (my camera hand isn't that steady :), but you get the idea.

With a multimeter on pins 6 & 7 of the PNP connector you can get a VERY good alignment, which saves having to hook up the battery & using a friend or mirror to watch the reverse lights.

Does this work in practice? No idea, but it seems like it should. Will this fix my problem? No idea, but probably not. The transmission fluid looks TRASHED. Gonna change that, then see how the test drive goes.

Here are the contacts themselves marked.