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Hello all,
Murphy struck again, waiting for freezing temperatures and a looming snow storm.
Suddenly my transmission wont shift into 4th.
On the highway 60MPH = just high of 3500rpm
The car is drive-able around town with some abnormal behavior with RPMs
and the engine seeming to be braking when letting off the gas peddle.
I see the overdrive solenoid is one famous problem and some people
have installed AW71 overdrive bypass kits.
https://www.ebay.com/itm/255655536375
I'm not towing anything and not driving up mountains, so wonder
if the AW bypass kit is a good option? What impact to fuel economy?
When I got the car I did flush the tranny with Techron full synthetic
and the fluid looks clean and is topped up.
Comments? Bill
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https://www.brickboard.com/FAQ/700-900/TransmissionAuto.htm#OverdriveRelay
If you find the fault is traced to the solenoid and you think the fix is adding a bypass plate I would grind a groove in the underside of the solenoid as described in the FAQ section above. The procedure is easy and it works.
I did this in the last couple of years and it restored the overdrive. Of course you lose the ability to shift it down to 3rd at higher speeds.
EDIT: I found the post and it includes the Oring information that I found at Lowe’s.
https://www.brickboard.com/RWD/volvo/1685245/bypassing_solenoid_restored_proper_engagement_od.html
--
Any twenty minute job is just a broken bolt away from a three day ordeal
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Hi Randy,
Thanks for that FAQ link, which somehow I missed before by selecting wrong keywords maybe.
It had a discussion of cold solder joints in the OD relay, which I thought
was OK since the shifter switch and downshift light was OK.
Then I checked the schematic and the solenoid and light are on different outputs.
The solenoid output on relay pin #87 had a confirmed cold solder joint.
I need to get on the highway to test, later, not now, with the roads covered
with school buses and wall to wall traffic. After confirming that it's fixed
you'll get the "Hero of the day award" and a free beer or three if you can find me.
My mailman dropped off the bypass kit just after finding the cold solder joint.
Happy new year, Bill
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I hope Thats it ! easier than having to get under the car that's for sure ,
Good luck.
Steve
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Hi Steve,
Yes, I don't want to be under my car in an icy/snowy driveway getting
soaked in transmission fluid.
But luckily the solder iron came to the rescue and the car is shifting into
4th gear just fine now.
Cheers, Bill
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I hope Thats it ! easier than having to get under the car that's for sure ,
Good luck.
Steve
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I hope Thats it ! easier than having to get under the car that's for sure ,
Good luck.
Steve
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I hope Thats it ! easier than having to get under the car that's for sure ,
Good luck.
Steve
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Hi,
Thanks for the feedback to everyone on the Brickboard. The size of an o ring can be vital information in every case of repairs.
It always helps to have two different sized shovels when digging for good “detailed” information.
🤔
Phil
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Kind of does sound like the solenoid is stuck. I've never had to do it and don't recall discussion here, but the bypass seems a good option. You only lose being able to hold or force a downshift to 3rd. IPD also has a bypass kit and cheaper than the Toyota one you found on eBay.
These AW71L trans are so reliable, even on a turbo, and it's amazing we don't have more issues like this at these high mileages. With that in mind I'd start with a good flush before going to all the effort of doing the bypass. You don't even have to crawl under if you want to skip the draining, just do a longer flush using more fluid and make sure you periodically run it through all the gears. I presume you checked the current fluid level while running. Have you had to top up in recent years? Has trans fluid been dripping on the ground? When was the last time it had a really good flush? Drained first? Synthetic? Shouldn't be it, but check for a sticky shiftdown cable just for the heck of it.
I recently did a pan gasket and it drained for over a week while I was working on trying to get the fill tube disconnected (had to resort to cutting it, should have done that right away, so simple and easy, HomeDepot for the brass fitting. ) I was surprised how clean the filter and pan were not having been flushed in well over 100k and the filter hasn't been cleaned in probably 300k (km). Switched to a good synthetic and shifting is as good or better than ever. I've been dealing with oozing fluid since the day we got that car and when tightening the pan no longer helped I finally dropped the pan, no gasket, just sealer, slowly going mushy. For some reason FCP was pretty much giving away good Corteco cork gaskets at around $2 each so got a spare for the other 940. All 100% now and a new trans mount bushing in the process that was starting to go. Now have to do a front mount with parts now on the shelf waiting for me to get round to having the time in warmer weather.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now
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Hi Dave, Happy New Year,
I flushed the tranny two years ago with full synthetic when I got the car.
This shifting issue is new, and there's no leaking tranny fluid.
After shipping, the plastic IPD kit is about the same as the metal Aisen Warner kit. I sprung for the AW that starts off in Chicago instead of the left coast.
Q: Can I get at the OD solenoid with the car on ramps?
Q: Does the OD solenoid have a connector down below ?
Assuming there's OD solenoid connector I'll pack it with Coax-shield
(Similar to duck seal) and tape it up in case I ever want to reinstall an OD solenoid for towing.
Q: Do you have a better idea for weather proofing that connector?
Some people have found frayed solenoid wires, so I'll know more when I get under there. Sometime after this weekend's slush storm at the coast.
Tel me about a "sticking down-shift cable"
Is that the cable from the tranny to the throttle rollers?
How-to confirm it's behaving and what to do about it?
Thanks, Bill
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Think you have the right cable. Been a long time since I looked at at AW70/71…:)
First, unhook the cable and try dribbling some ATF on the cable and down into the cable housing. Try to work it in. If lucky that might work. The cable should move freely.
Check this link:
https://www.brickboard.com/FAQ/700-900/TransmissionAuto.htm#Kickdown_Cable_Adjustment
- Read Failure Mode section -
Happy New Year BB!
JW
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Will I buy another Volvo??? We'll see....
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Hi Jim,
Happy new year,
Things can only get better.
...and I have a bridge I want to sell you...
Kidding aside, lets hope for the best.
Thanks for the FAQ link, I came up empty with the search entries
here "Overdrive bypass" etc.
I'll check out that cable again tomorrow morning before the killer
slush storm erupts, then freezes. Yikes!
Meanwhile Steve (0 1 11) reports he's been victimized by an OD solenoid before, so maybe its an automotive version of an appendix,
and unless you're towing you can forget it?
I'll let you know after the official OEM Aisin Warner bypass kit
(fancy name for an O-ring and cover plate) gets installed.
Stay out of the hot sun, Bill
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Bill,
What hot sun? ☀️ 🌞 We live in New England. 🙃
This might be helpful. Just remembered this drama. I had a similar issue with my 90 240. No OD. I too thought it was the OD solenoid. Was preparing to replace it. On the 240 you could reach it with jackstands (I’m sure ramps would work) but it is in a difficult spot. So, I considered replacing it or installing the bypass kit. Then I got lucky. Read on the BB about folks having issues with the wiring running to the solenoid. The wiring rubbed on the almost sharp bottom edge of the transmission tunnel near the shifter opening. Wire was bare and badly corroded. Replaced wiring and voilà OD was back! BTW - Another spot the wiring can go bad is where it connects to the solenoid. This wiring issue might not apply to 940’s but still worth checking out!
Personally, I would only do the bypass as a last resort. Try every other possibility first.
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Will I buy another Volvo??? We'll see....
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You're right about 700/900s having a similar OD solenoid wire exposed to damage like 240s. I had initially wondered about that possibility, but Bill's problem is not getting into 4th. The OD would need to be permanently engaged. I don't see how a broken solenoid wire or short to ground could do that.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now
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Wo Cowboy. Think you need to reread Bill’s first post and my previous post. I have no idea what you are talking about?? As I stated in my previous post on my 90 240 the solenoid wire was shot and the tranny wouldn’t shift into 4th (OD). Stayed in 3rd. Same problem as Bill - AFAIK. If the OD solenoid is not getting juice then the transmission will stay in 3rd. Simple as that. Been down that road….
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Will I buy another Volvo??? We'll see....
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Ah, so I have the solenoid operation backwards in my mind then? The initial state of the solenoid is then for maintaining 3rd and it takes power applied to the solenoid to let it go up to 4th, as in "go into overdrive". In the 900 manual Volvo calls the circuit "AW70/71 overdrive with kickdown inhibitor" which somehow misled my thinking. In that case you're quite right and the prime suspect and first thing to check would indeed be that exposed wire hanging there, not the solenoid itself. Anecdotally here the solenoids are not known as trouble spots. I've spent a fair bit of time crawling under a trans in the past year or so and always make sure that wire will stay away from the linkage or chafing on the body. There are also a number of flex failure and possible pinch points, including at or in the shifter assembly plus there's the thin wires to the OD switch that flex in their small harness close the base of the shift lever (they don't go all the way down and out the bottom, just inside the handle).
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now
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Great to see Klaus back on the AWD forum. Miraculous recovery! Getting off the crappy drugs was apparently the trick. He sounds great! 👍
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Will I buy another Volvo??? We'll see....
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