300K miles. Trans pan gasket was leaking so I removed the pan, replaced the filter and pan gasket, and refilled with new fluid. Afterwards it won't shift into overdrive (4th gear). The OD solenoid circuit is working; I've done multiple things to confirm that the OD solenoid circuit is not the problem. After reading some other threads about overdrive problems I'll probably try a flush next, in case there's a blockage within the valve body that's preventing the trans from shifting into 4th gear. I already ran the engine with the trans in gear while the OD solenoid was removed, and got a good spray of fluid. My suspicion is that the valve body needs to be rebuilt. Other than the front and rear seals in the trans being replaced at about 150K miles, the trans has not had any work done to it. I welcome suggestions. Thanks

The OD problem has been resolved. I replaced the OD solenoid with a solenoid bypass device that many folks have referred to. I got it on ebay for a little over $20. The trans then started shifting into OD. I drove the car that way for a few weeks and then reinstalled the OD solenoid. OD and the OD switch are working normal again.

Though I had previously flushed the OD circuit within the trans by briefly running the trans in gear in the garage with the OD solenoid removed, apparently that wasn't enough to fully clear and/or prime the OD circut within the trans. From the look of the bypass device I'm sure it flows more freely than the OD solenoid, and with the bypass device on the trans the trans was finally able to shift into OD. Then once the OD circuit within the trans had been cleared/primed/exercised it was able to function again with the lesser flow provided by the OD solenoid. At least that's my theory. Glad it's working again.

Thanks everyone for the help.

Hi there!

Glad to hear you got the Over Drive working!

I think your theory is as good as mine, in that it was a flow/ pressure issue.
A restriction or cavitation bubble is all part of it suddenly not working the shuttles.

Could you post a “link” to the part you found?
I’m not too familiar and highly knowledgeable on these automatics!
Since I have only one automatic, that coming up for a fluid change, I may need your fix for my 1992 240.

Phil

here's my experience. i had a bad solenoid so replaced with new and verified working and not something else like the relay. still would not shift to OD. ran car in drive for a very brief period with solenoid loosened which ended up correcting issue. i know you said you did this but maybe try again? it's messy i know but worked at least for me.
--
'91 244 205k auto

Dear silvermine,

Hope you're well. By "solenoid loosened" do you mean that you did not fully tighten the two bolts, that secure the overdrive solenoid to the transmission case?

If so, how did you keep transmission fluid loss from damaging the tranny?

Does "very brief period" mean two minutes, five miles, or something different?

How much trans fluid did you have to add, to reach the right mark on the dipstick?

Thanks for your help!

Stay well!!

Yours faithfully,

Spook

yes loosened bolts. it was done on a lift for only about 5-10 seconds. then tighten bolts, clean up mess, and top off fluid lost.
--
'91 244 205k auto

Dear silvermine,

Hope you're well and stay so. Thank you.

Your reply is hugely helpful! It sets forth how to flush the area around the over-drive solenoid, to dislodge "crud" that may interfere with proper functioning. I'm not sure an ordinary transmission flush does this.

Thus, your idea - to do a separate flush of the solenoid - adds to the troubleshooting knowledge base.

Stay well!

Yours faithfully,

Spook

Hi,

I suggest you try a few things.

You might want to check the kick down cable for some "slack" up at the throttle body.
If you pull it, there should be a very slight click down in the transmission.
If the cable is too tight or has stuck with the cable pulled back, the transmission will not know that you are not wanting to get into the next upper gear or into overdrive in your case. So it stays locked out from the governor influence.
When you want a lower gear, the cable is pulled by the throttle opening near wide open.
Depending on the speed of the transmission "turning over" a governor decides which lower gear you will get shifted down into and how long it will stay in that gear.

The solenoid in question is an electrical component to lock out the overdrive. It stops short term oscillating on grades or engage down hill engine braking.
On the manual M46 overdrives it engages the overdrive "by opening" a port passage, in the valve itself that allows flow.
I'm not familiar with this on automatics as I have only one car out of six with an automatic transmission. It might work the opposite in an automatic. You should be able to blow air in one position and not the other of their energized states.




The governor system, inside the automatic transmission, is pressure and or flow sensitive to "shove" shuttle Pistons over certain canal ports. In many cases they can use preset spring pressure and shims during manufacturing. One overrides one against another.
It's imperative that things are kept clean with regular clean fluid changes.

Tarnished or varnish, take your pick, is the battle. Letting cars sit is one problem with automatics and why I have so many manuals.
I still have the fifth gear ATF issue concerns but not as complicated.
Has the car sat a lot or not used to shift down very often?
My M46's like being used regularly or they can get sticky or slow to fully engage.
Your overdrive could or should engage above 35-40 mph when you want it to coast along but drop back if you want to accelerate moderately well. This keeps the things, in there, working freely.

When you drive the car, try to use the kick down feature in the lower gears (2nd back to 1st) and then (3rd back to 2nd).
You might need exercise the governor through some cycles to get fluid to get up in the valve body with more surge!
The higher revolutions may help push air out of a cavity or possible trash that got disturbed.
Trash or an air bubble can get caught in a pocket or the turns in the valve body vanes or galleries.

It's possible that it might just start working again, when it get good and ready.
You might have to be patient or try some purposeful transmission additives that might dissolve trash or varnishes.
You may want to research what Aisin transmission company recommendations are or ask a some knowledgeable and "experienced" transmission mechanics.
That will be tough to get to with "stupid" service-writers, ex-salesmen or money grubbing owners blocking the entrance of some shops!

Good luck!

Phil

Ive been struggling w my 93 945 for the 5 yrs I ve had it,,it only got around 17 mpg,,,replaced almost everything,,The Kickdown cable was hanging up & I got my mechanic,Jim Bobbit Phillipsburg,NJ to replace the cable & change filter & gasket,,wellla!! Smoooottthhhhhh driving like new!~!! 24mpg after driving 200 miles!! GOT THe car at 200k & now its near 300kk so maybe replacing the kickdown cable its long overdue..
by the way,,,w a 245 that i had used a thicker outer oring to bypass the solenoid,,,instead of cutting a groove,,& that car went into 4 th where it never went previoously.
ZEasy to try to see if that works,,

Thanks. I did pull the kickdown cable to make sure it's not stuck and that it clicks when pulled out, and I also drove with the kickdown cable disconnected, and it behaved as expected, but it still wouldn't shift into 4th gear.

The car had not been sitting a lot before this all started. It started when I replaced the pan gasket due to it leaking and in the process also replaced the filter and refilled, which had not been done in longer than it should have been done. The old fluid was dirty, but there was no crud or sediment in the pan.

As for the OD solenoid, I've done enough testing with it, and with a spare I got from the salvage yard, to satisfy myself that the problem is not the OD solenoid.

I'll probably give it some more time to see if it corrects itself. The car isn't driven every day, but it's driven at least several times a week.

Are you sure the solenoid needle is lifting for the over drive. Just clicking is not enough. Power to the unit. Were the test you did with the valve bench tested ? .Are you getting power back at the transmission ?

I removed the solenoid and bench tested it and confirmed that it flows when engergized, and it sounds the same when it's on the trans and the OD switch is pressed on and off. I also pulled a solenoid from a 740 trans at a salvage yard and did the same test with it, and also installed it on my trans, and I got the same result. I'm fairly certain the solenoid isn't blocking flow. But I've not tried a solenoid bypass like I've read about. I might try that. Thanks

While it does seem unlikely that two OD solenoids which are both clicking away would both be faulty, it also seems unlikely that an otherwise working AW70 transmission would have such a serious fault within valve body/trans without other systemic symptoms.

So I suggest this: Since you have two solenoids, cannibalize one to remove the solenoid, wiring, relay, and switch from the equation. It requires a bit of time with a Dremel tool, but it's cheaper and easier than replacing a trans or valve body.

My favorite post on the subject: https://www.brickboard.com/RWD/volvo/737816/volvo_240_automatic_transmission_overdrive_circuit_spellchecked.html

Best of luck,
Will
--
XC60 / Odyssey

Suggest flushing with the cheapest possible fluid then refilling with synthetic ATF. Synthetic ATF and PS fluids have worked wonders in a few of my cars.
--
Will I buy another Volvo??? We'll see....

I did the flush & fill and filled it with full synthetic. I drove it about 40 miles including about 20 on the interstate. No change; still won't shift into 4th gear.

It might take some time for the synthetic to do its “thing” and clean the internals like the valve body. I had a steering rack leak on my 95 855 GLT. Flushed the PS fluid and replaced with Mobil 1 synthetic ATF. About a month later the leak stopped!

Also check the filter as suggested.
--
Will I buy another Volvo??? We'll see....

Can't shift up to 4th? Sounds like a flow issue. Do you still have the old removed filter? IIRC the filter element for these trans supposed to be a fine wire mesh not filter paper type. Check if you have the correct filter type installed. May need to remove the pan again and see for yourself.

Amarin.

Thanks for the suggestion. I don't have the original filter, but as I recall the replacement filter looked the same and is made of fine wire mesh.

If the rate of flow from the return line from the cooler during a power flush is any indication of whether there is good flow, I would say it has good flow because the last thing I tried was doing a power flush and going back with full synthetic (I had not used full syntethic following the filter replacement, and someone suggested I do that, so I did that yesterday). During the power flush there was good flow from the cooler return line. It filled the catch jug fairly quickly.

Dear Amarin,

Hope you're well. You're correct: the Model 71 Aisin-Warner transmission filter is made of a very fine wire mesh.

Hope this helps.

Stay well!!

Yours faithfully,

Spook

I'll do that this weekend and will post the results. Thanks

just replaced the kickdown cable on my 285,000 945 & It makes a BIG difference,,,really drives much smoother~!!

get various o rings & take the small o ring off & put a thicker o ring on then the solenoid,,,that will allow it to go into 4 th .Then if it doesnt you will know its trans valve? If it doesnt go into 4th u know its the solenoid not engaging

my 940 is around 300k too & it shifts fine, so the flush may do the trick,But I would think it may be the solenoid,I got 1 for a 240 off ebay that works great I think it was only $40,,,

Thanks. I tested the OD solenoid and also replaced it with one that I picked up from a salvage yard, which I also tested. I'm confident that both solenoids work, and I think the problem is likely internal to the transmission. I plan to do the flush procedure this weekend and will post the results.