I just helped a friend replace his stick-shift with an AT. No problems except: I expected the wire connector for the OD relay to be sitting above the heater and just to the left of the glove box. I found nothing.

Am I just not looking closely enough? Or do I need to add that wiring in?
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240 drivers / parts cars - JH, Ohio

I have to echo the question

Why would you do that??

you do not need wiring....there is some info on this site, take the solenoid off and dremel a path between the holes , replace with a new o ring and you have overdrive. I have done on 3 cars, works great!

Kris

Thanks for the feedback.

Axle: If I remember correctly, the sticks are 3.31. It's a big drop from 3.73. We haven't changed the axle because it's a lot of work when there's corrosion. We'll see how it goes. I had a 245 AT conversion for a while with the stick axle. With a load it lugged on hills and I downshifted fairly often. I sold it to a friend who commuted on a highway. He kept the old axle for the MPG. But I think that works the engine too much ie. you're often out of the good RPM range.

OD: It hadn't occurred to me to wire it directly ie. I thought you'd need a relay. Not sure why: it doesn't take much amperage. The OD solenoid on the swapped-in AT was bad and I cut a groove in it to bypass. But this exacerbates his problem of having a high-ratio rear axle.

It that how your OD is set up - a switch on the dash?

Why: I think he'd replaced the M47 at least once and had ongoing problems with the cable. And maybe an oil leak that ruined the clutch plate. He had the spare AT setup and sold the conversion set for more than he paid for the whole car. I enjoy a stick - I have a truck and a 245 - but I think I've had fewer problems with the ATs.
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240 drivers / parts cars - JH, Ohio

With a load it lugged on hills and I downshifted fairly often. I sold it to a friend who commuted on a highway. He kept the old axle for the MPG. But I think that works the engine too much ie. you're often out of the good RPM range.



Boy are you right. It's what I'm fighting with right now. It doesn't help that my other 240 has the 3.73 axle and I can feel the difference in drivability. I commute in Northern VA, the metro DC suburbs, and never get more than 30 seconds at a stretch over 40mph. Ugh.

My OD is wired through a spare emergency flasher switch. It's the only stock 240 switch that can light up the OD arrow on the gauge cluster when you cut power to the solenoid. Actually, in my wagon with the manual-to-auto swap, I used a seat heater switch, and I use it OFTEN to keep the rpms in the right range for fighting stop and go traffic.

Time for a 3.73 rear, but not sure if I should swap the ring and pinion or the whole rear end.

And I thought I was unique in using a flasher switch instead of relay.Been
working fine for our only auto for over 10 yrs
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Rene

I haven't swapped a ring & pinion in a long time (and not on a 240). I remember fussing with shims, plastigauge ....

Northern VA: ~Winchester area? Yeah, that's hilly enough. Hard on the mains. A 3.73 would make all the difference.

OD toggle via a heater switch: what an awesome idea.

A while ago - before I had many spare parts - the OD button on one failed. I taped a button to the shift rod and ran the wires on a handset cord. Temporary fix for several years.
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240 drivers / parts cars - JH, Ohio

It would make far more sense to swap in the entire axle assembly set up by Volvo. You'd be opening a whole can of worms regarding shims/clearance if you wanted to swap the components into your current housing. -- Dave

The reason for the relay is not as much current through the switch as it is affording alternate action hand on the shifter control and default OD=on when the car is started. The harness is not there on M47 cars.

There's one more gotcha on the "Jorrell" swap, when applied to an 89. There's a violet wire at the 9-pin cabin harness to LH harness junction which selects the ECU function for shift indicator. This shares wiring with the cluster's OD OFF indicator, so if not unpinned, gets a resistor inside the ECU smoking hot. But this is only a problem if the auto overdrive relay harness is installed.

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Art Benstein near Baltimore

If life gives you llamas, make llamanade.

Thanks Art. yes, right, a relay lets you have a small/micro push-on push-off switch.

AB: "There's one more gotcha on the "Jorrell" swap, when applied to an 89. There's a violet wire at the 9-pin cabin harness to LH harness junction which selects the ECU function for shift indicator. This shares wiring with the cluster's OD OFF indicator, so if not unpinned, gets a resistor inside the ECU smoking hot. But this is only a problem if the auto overdrive relay harness is installed.

JH: New to me. Then, if you push-off the OD and indicator, and then bypass the OD, the resistor in the ECU gets hot? And/ or if the OD wire fail?
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240 drivers / parts cars - JH, Ohio

I have one of the only other manual to automatic swaps you're likely to find. The previous owner (jorrell) made the conversion. I have dug through the wiring in the car and have not found the OD relay conntector. However, I recommend leaving the wiring for that system out altogether. Having a simple switch on the dash is much less problem prone, and much easier to wire.

Just curious - what was the reason for the swap, and did you change the rear end to the 3.73 found on automatics?