Volvo overdrive question
 

I have a Volvo electric unit in my Model A that I can't get to engage. It's a 12v.unit and I'm still using 6v. I was told by others that they have them and they run them on 6v. I have it grounded to the frame and to the tranny. I touched a 12v battery charger to the solenoid and it clicked so do you think using a 12v inverter to the overdrive would make it work? It would be easy to mount the inverter under the seat

Re: Volvo overdrive question
 

I gather from the above that 6V won't make it click. If that is so you could test it with a 12v jumper battery to make sure everything else is doing what you want it to. Even a motorcycle battery should work, if it does, then put the inverter under the seat. Be sure to have a block out switch so that you don't put the transmission in reverse with the OD engaged. Bed things then are very likely. I did my block out with a micro switch on the transmission that was activated whenever the shifting fork rod was placed in the reverse position, that then cut all electrical current to the OD. Very nice units, I might add.

Re: Volvo overdrive question
 

Your problem may not be electrical. You might want to check the oil level. A Volvo overdrive is different from a Borg Warner. Instead of a big solenoid I believe it is some kind of a servo valve that actuates to port oil to cause it to shift. Loss of oil is usually through the rear seal and the oil will end up in the banjo. A good idea to also check the banjo to see if it has too much oil.

Tom Endy

Re: Volvo overdrive question
 

you also have to be going fast enough for the pump to engage the clutch. Go on the gear
vendors site, they use that unit for their overdrive set ups. Lots of information

Re: Volvo overdrive question
 

I have been using a Volvo OD for 5 years that I made up from parts. Works like a dream on 6V. I have heard others who have small oil leaks from the OD say that they have to top-up the oil for it to shift properly.
Geo.T

Re: Volvo overdrive question
 

When you have tried the electric and filled up the oil, if needed, you might want to check the pressure in it.
Volvo-guys told me, and I had to shim up my valve spring in my 221 years ago, and it worked very well afterwards.

Re: Volvo overdrive question
 

Hi I have had my Volvo for over 10 years, the solenoid will work just fine on 6 volts even though it's rated for 12 volts.
Try running a jumper wire directly from the battery to see if the solenoid clicks, it should, just like your test with 12Volts.
If it clicks, check your switch and or wiring to confirm you have 6 volts on the solenoid.
Like others have said the pump is driven off the shaft and needs to be turning to generate pressure to engage the cone clutch to shift into overdrive.
Oil level is important also the type of oil you use. Depending on pump wear, you may have to try a heavier oil. Mine won't shift with ATF on hot days so I use 10W-40 motor oil in .
Hope the above helps.

Re: Volvo overdrive question
 

British Motors told me to use Castrol 20/50 in my Austin Healey's, so that was what I used in my Model A also. I no longer have the car, but when I last checked it was happily driving around Yerrington Nevada where it has been for several years. Never had one leak that I know of, but they ran off the tranny oil in the A/H and those always leaked a bit.

Re: Volvo overdrive question
 

Thanks for all the tips guys. I got the unit from a guy in California and he said it was built by Rich Little, but when I sent them pics of it they said it wasn't one of their units. Anyway, I filled the overdrive unit with 10-40 oil and Rich sent me a wiring diagram and a new switch for activating the OD but so far no luck. I think I used a 6 or 12v charger directly to the solenoid and nothing on 6v but it clicked on 12v. I have a micro switch that cancels the overdrive when I put it in reverse that I got from Rich as well