Amazon: overdrive drops out when cold

[gjr0]

'67 P220
Just recently the temperature dropped into the low 30s- high 20(F) in the morning. This morning when I turned on my overdrive it would disengage and the car would be in 4th. Then it would engage and be in overdrive, several times in a minute.

I left it in 4th gear for a while. Once it warms up, after driving 6-10 miles, it works normally again. Same thing coming home this afternoon but now the temperature is in the 50s.

Any idea what is going on ? I checked the gearbox oil when I changed the engine oil, about 900 miles ago and it was fine. What else to check ?
Thanks
Greg

[Othen]

Originally Posted by gjr0

'67 P220
Just recently the temperature dropped into the low 30s- high 20(F) in the morning. This morning when I turned on my overdrive it would disengage and the car would be in 4th. Then it would engage and be in overdrive, several times in a minute.

I left it in 4th gear for a while. Once it warms up, after driving 6-10 miles, it works normally again. Same thing coming home this afternoon but now the temperature is in the 50s.

Any idea what is going on ? I checked the gearbox oil when I changed the engine oil, about 900 miles ago and it was fine. What else to check ?
Thanks
Greg

It sounds like an issue with the solenoid. I suspect there is only a coincidental connection to the temperature.

Do the easy things first: check the solenoid is getting power from the switch (and that the inhibitor switch is providing a good connection in top gear), that it has a good path through the coil to earth (low impedance). You should be able to do all that from underneath the motorcar without any disassembly; you may see where the solenoid is located in this photo:



... as long as the issue isn't to do with the inhibitor switch (which is a bugger to get access to).

Good fortune,

Alan

[Derek UK]

I would recheck the oil. I think the level is more critical if the various internal O rings get a bit tired. But, I agree with Alan about the solenoid. The power wire that goes in via the domed rubber cap is prone to coming adrift inside and may be making hit or miss connection. Peel back the cap and check. It shouldn't be all that oily in there either. Removing the solenoid is easy if you have re solder the wire back on.
Yesterday I posted a similar reply on Brickboard
https://www.brickboard.com/RWD/volvo...overdrive.html

[142 Guy]

I am presuming checked the gearbox oil meant the level? What weight oil are you using? Also as a last resort clean the suction filters. Lack of oil pressure will cause the OD to drop in and out of engagement. Heavy oil combined with low temperatures along with dirty filters will contribute to the problem.

[gjr0]

I'm using 30 wt oil in the transmission and overdrive. I did not clean the pick up screen when I changed the oil in the transmission.

Where is the solenoid covered ? It is not in the electrical nor the overdrive sections of the shop manual.

What do you think of using 15W-40 diesel motor oil in the transmission and overdrive ?

Today the morning temperature was in the low 40s and it worked fine. I'll check the solenoid wiring and clean the pick up screen this weekend.

Thanks for the help.

[Othen]

Originally Posted by gjr0

I'm using 30 wt oil in the transmission and overdrive. I did not clean the pick up screen when I changed the oil in the transmission.

Where is the solenoid covered ? It is not in the electrical nor the overdrive sections of the shop manual.

What do you think of using 15W-40 diesel motor oil in the transmission and overdrive ?

Today the morning temperature was in the low 40s and it worked fine. I'll check the solenoid wiring and clean the pick up screen this weekend.

Thanks for the help.

The solenoid is covered in the Volvo Green Book at Part 4 (43a) Overdrive in pp 4-2 and 4-3.

I’m suggesting that you check the solenoid first because it is something you may do without disassembly. It is also a plausible cause for the OD engaging and disengaging frequently. I think the temperature thing might be a red herring.

Good fortune,

Alan

[142 Guy]

Oil recommendations are varied for the OD equipped boxes. Early A type was SAE 40 motor oil. On my 1971 M41 with P type OD, Volvo recommends SAE 30 or SAE 20W40. However, Triumph recommended 80/90 Hypoid gear oil (not GL5) for the P type on their cars. 80/90 gear oil has a viscosity similar to SAE 30 motor oil.

All of the recommendations are 1/2 century old and the oils that were recommended no longer exist. Your SAE 30 motor oil is consistent with Volvo's recommendations from 50 years ago so is not incorrect. If you are using a conventional oil, synthetics generally have a flatter viscosity profile than conventional oils. They may both have the same viscosity at the 100 C test condition; but, as the temperature drops the conventional oil can start to look like Marmite whereas the synthetic remains closer to its test viscosity. So a synthetic engine oil may work better at low temperatures because it is more pump-able. There are synthetic manual transmission oil that will work well in the M41 with the benefits of the flat viscosity profile. I have been using Red Line MTL for about 20 years which has friction modifiers that improve the operation of the synchro rings. The down side to Red Line is that it has become ridiculously expensive.

Othen is correct that a loose electrical connection to the solenoid or an internal intermittent problem inside the solenoid will also create these symptoms. The problem with the internal intermittent solenoid problem is that unless you are lucky and happen to test it in the failed condition it is not a testable condition. You pretty much need to diagnose by replacement. Of course, waiting until it stays dead and then testing is an option.

I offer up my own experience. I have had three cars with J over drives. A 1971 142E, a 1979 242 GT and a 1987 745 turbo. All of them developed OD drop out problems around 6 - 7 years of regular use and all of them were resolved with an oil change and filter cleaning.

Of course, your problem can be more serious involving wear in the OD hydraulic pump circuit which involves a pressure test. However, you have to start the diagnosis some place. You get to choose. Check the solenoid or check the oil / filters. If you do clean the filters you will need a replacement gasket for the filter access plate on the OD.

[c1800]

I have been using Red Line MTL for about 20 years which has friction modifiers that improve the operation of the synchro rings. "

Works a treat , improved OD and trans operation in my '71 1800e. smoother shifting.

[gjr0]

"The solenoid is covered in the Volvo Green Book at Part 4 (43a) Overdrive in pp 4-2 and 4-3."
In my manual page 4-2 is a list of tools and 4-3 has a couple paragraphs about how the solenoid operates but nothing on testing.

Hopefully it is not the pump...

[142 Guy]

The most basic test would be to check for electrical continuity between the solenoid terminal and the case. The solenoid uses ground return. No continuity = definitely dead. The other basic test would be to apply 12 V to the solenoid terminal and listen for a click.

More than you ever wanted to know about over drive units here:

https://volvo1800pictures.com/docume...20shooting.pdf