Simple question: I have a 68 wagon retrofitted with OD. The setup was made directly to a dash switch without the use of a relay. The switch routinely burns out, and I'd like to put in a relay to handle to load. Is there a standard NAPA/etc relay I can use for this? I assume it's a pretty basic connection.

Colin

Thanks all. Good news from under the car. It's an M41, and I do have the lockout switch in place. It has the long top with the 1800-style shifter extension. As a result, I have a short shifter at the near end of the modified trans hump, rather than the usual 120-style long stalk shifter. I believe the overdrive is a J-type, with the solenoid on the driver's side.

I think I'm going to install the toggle switch on the dash with an OD ring and a green OD light I have from an 1800ES. I'll start looking for the proper relay - volvo #1259750 from a 240, or a reasonable equivalent.

Does anyone know what to ask for when I get a new speedo cable for this setup? I remember hearing that these were hard to come by.

Colin

I'll find the picture/diagram of how to wire the OD relay, and post it.

A used relay should run $10-$15 from ebay, junkyard, or volvo classified ads.

Paul

Note: the two wires going to the sugar cube relay (#30 & #87) can directly go to a momentary switch mounted on the dash. The sugar cube relay is only used if the turn signal headlight momentary switch (momentary ground signal) is used to activate the OD. The 240 relay needs a momentary power signal.

Paul,

Thanks for the excellent diagrams. Pardon my stupidity, but regarding the 'momentary switch' options, would the old on-off Lucas switch on the dash be attached to the wires going to 15 and 86 on the 240 relay? Or is this switch not a momentary switch?

If not, can it be used with the 240 relay? Do I need a switch that briefly completes the circuit then returns to off?

Make any sense?

Colin

Purchased a speedo cable for my D type overdrive recently (part #670505); no problem at all tracking it down. I bought mine from VP Autoparts

www.vp-autoparts.com

You may find this useful: http://216.160.8.21/RWD/index.htm?id=695288
Bob S.

Thanks. Cool setup.

I guess if I don't have the 4th gear lockout as an option, I could use this dual-relay setup with power from the reverse light relay triggering the door lock relay to turn off the overdrive. Kind of a triple switch which would at least keep the OD from being engaged when reversing.

Would this work, or have I reversed the on-off function of the door lock relay when power is delivered (ie, power from the reverse relay needs to turn off power to the OD relay)?

Colin

Colin,
Being anything but knowledgeable about electrical stuff, I hesitate to give advice on anything I haven't tried myself. Here are some observations, though:
a) You are aware, are you not, that the door lock relay is only to change the action of the headlight flasher from contact-to-ground into current-to-something-else and is not needed if you use a momentary switch to give a power jab to the OD relay to stir it into on and off action?
b) As I understand it, the 4th gear switch completes a circuit from terminal 85 on the OD relay to ground. This makes the relay send power to the OD solenoid that keeps the OD working as long as power goes to it. So, if you can rig something from your back-up light switch, which is a switch to ground, or the back-up light relay that cuts the power from the OD relay to the solenoid or between the fusebox and terminal 15 on the OD relay when you engage reverse, that should do the trick. But as I said, I'm out of my depth here, and I'd much rather have you follow someone else's advice.
Good Luck,
Bob S.

You don't have a 4th gear lockout, or is it not hooked up???

You should use a 4th gear lockout, no advantage to have the overdrive engaged in 1st-3rd gear.

Paul

I'm not sure I have it. The OD was fitted by the previous owner, and I have yet to crawl up under there and see. The od is currently hooked up with an internal switch, and engages from all gears. The lockout switch might be there, but incorrectly hooked up, or maybe not hooked up at all.

I'm hoping I can visualize it either from below, or through the shifter hole. I'm not excited about dropping the transmission just to see if the switch is there.

For reference, what side of the gearbox lid should the lockout switch be on?

Colin

The 4th gear lockout is located on the tranny cover (hexagon shaped switch ~1-1/2 inches in diameter with 2 wire prongs). It's the only switch on the cover (It's the only thing on the cover, actually!) You should be able to see it from the shifter hole.

From what I remember, it's on the right side, ~ in the middle.

Paul

BTW-is it a D-type (solenoid on the right->passenger side) or a J-type(solenoid on the left->driver side)overdrive M41 Tranny?

It's more towards the left side of the cover. Some covers also have a switch towards the right, which is the reverse lights, but some use a different system for that.

Hey! I posted that 240 relay setup thread way back when. I have pictures of the setup including a diagram of the wiring.

The main relay used is from the 240 overdrive setup. The M46 and M41 J-type overdrive solenoid are the same, so I know that the relay used to operate the solenoid is the correct overdrive relay as designed by Volvo. I worked at a Volvo shop when I was in college in the 90's, mostly on the 240/740 models (some 140/120s), and feel comfortable with those components.

I think the original thread started here:

http://216.160.8.21/RWD/index.htm?id=689044

Let me know if you would like me to post the pictures/diagram on the 240 relay setup.

Paul

BTW-My '65 122 has a B21/M41 running in it. The B21 almost looks like it belongs.

Just checked out the tech article on this on Vclassics. Great diagram c/o Phil Singher. Still wondering whether I need a specific relay, or whether a generic one can be used from a parts place.

I'm also not sure I have the lockout switch on my gearbox, as OD will engage from any gear. Is this also retrofittable or is it specific to a certain gearbox?

Any relay will do it, it can be as fancy or as simple as you want. As far as the wiring is concerned th P.O. has already shown that their wiring skills were limited, there is a chance that the 4th gear "lock in/out" switch is there but not wired in and this is a risk, as having the o.d. in reverse will destroy it. That being said 8 forward gears sounds fun (but is probaly more torque than th eo.d. was made for), someday I may get creative and wire up my 120 so that the reverse switch locks out the o.d. and try 8 forward.

Anyhow, the 4th gear switch if present is on the gear box top cover, getting to it, ot even seeing if you have one will probably require taking out the tranny x member bolts and removing the shifter, and lowering the tranny as far as you can (loosening the engine mount bolts as well helps, just make sure you don't force the fan into the rad). Once you have done this you should be able to see if you have the switch.
If you don't you can scrounge around for a top that has the switch or you can get the measurements and remove your top and tap it for the switch, or you can wire something up so reverse switch disables the o.d., or you can use the 240 o.d. relay and put a switch on the clutch pedal so that pressing the clutch disengages the o.d. How many ways can you skin a cat?