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Transmission was operating fine until the arrow warning light and winter/sport/economy switches starting flashing after a 10 mile drive. Drove it another mile to my house and lost drive and reverse entirely. Let it sit for 10 minutes and was able to drive the car into its parking spot. Fluid looked clean, so I took it to a shop that could read the diagnostic codes. Codes were:
AT-232 - speed sensor absent
AT-114 - mode selector switch signal
AT-341 - lock-up function slipping
They suggested I troubleshoot the circuits involved in sending the speed signal to the transmission. So I first checked the harness connectors underneath the transmission and near the dipstick area. Test drove car and had same symptoms: severe slippage on a hill, but able to move after 10-15 minute shutdown. Since the speedometer works during these "breakdowns," I figure the speed sensor in the rear axle is working. I removed the instrument cluster and checked continuity from the speedo to the transmission control module. Also, from TCM to ground. Swapped the transmission control module with another one. Car continues to drive OK for a few miles before severe slipping reoccurs.
Interested in Brickboarder's experience with these codes and/or problems.
Have a happy 4th!
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I agree with the others. Try a thorough flush first. Flush with the cheapest fluid you can find then replace with synthetic ATF. May not solve the problem but is worth a shot since it is so cheap.
If that doesn’t work I would investigate the 2 non-speed sensor tranny codes further. I don’t think a bad speed sensor will cause slippage. The logical one to pursue first would the lock-up function slipping. Have you tried the Matthews Volvo website yet? There are problem lists there for the various Volvo models. Maybe you can find someone who has had a similar problem with their 960 and hopefully find a solution.
To be honest the slipping when warm issue bothers me. Had a similar issue with the first of my 2 850’s. The slipping on that car only got worse. Hope you have better luck!
--
Will I buy another Volvo??? We'll see....
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Thanks for responding to my problem. Re. the fluid flush, please see my response to Volvo426. I searched Matthews as well as Brickboard when problem first appeared. One thing that comes up on both sites is that transmission has a good reputation for longevity. Miles (documented) on mine are less than 150K and I've gotten at least 170K out of all the AW transmissions I've owned. My 940 was pushing 250K and still shifting fine when I let her go.
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Yes, AW’s are excellent transmissions most of the time... But I’ve read here about early failures in 240’s, 740’s and 940’s. 850’s have AW transmissions too. Also bulletproof (normally). Just sold my 95 850 with over 250k on it. Shifted great no problems! Sold my 90 240 with AW70 at 300k. Original transmission, still going, but leaked like a sieve.
I suggest not driving your car any distance until you fix the problem. The heat will do it no good. Probably make the slipping worse. Burned clutch plates did in the AW in the 93 850.
--
Will I buy another Volvo??? We'll see....
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Dear analogdad,
Hope you're well. I note your comment, "the fluid looked clean". Failed automatic transmission fluid (ATF) need not be dirty. When was the last time the ATF was changed?
Because the problem recurs once the ATF reaches normal operating temperature, I suspect the fluid is simply "worn out". At normal operating temperature, viscosity declines. Fresh fluid can accommodate this. "Worn out" fluid cannot.
See the FAQs for the ATF flush procedure. I'd flush with WalMart ATF, using 12 quarts. If that produces an improvement, drive for 1,000 miles and reflush with Mobil 1 (or similar) full synthetic ATF.
Please report on your findings.
Yours faithfully,
Spook
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Hi Spook! thanks for responding to my problem. Re. fluid changes, please see my response to Volvo426, and let me know if you have any other suggestions.
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Dear analogdad,
Hope you're well. Yes. Check the ATF level. If it is too low, the heat rise during normal operation may become disruptive, if there's too little ATF to absorb and dissipate the heat.
Next, if the recent flush/refill with synthetic Autoomatic Transmission Fluid (ATF) was the first, it is possible that "crud" dissolved by the new ATF interferes with the shift solenoids. Was the pan pulled and the filter inspected?
Before pulling the pan, I'd re-flush, being sure to have someone move the shift lever through the gears, while fresh ATF is added and old ATF leaves. This will help to ensure no "crud" is trapped in the solenoids.
Hope this helps.
Yours faithfully,
Spook
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Spook,
Thanks for your additional suggestion! I like your rationale for flushing again. The service history for this car shows it was only serviced at Volvo dealers and - as you know - Volvo did not call for EVER changing fluid in this tranny. Therefore, there was likely plenty of "crud" for the synthetic fluid to dissolve. I haven't pulled the pan/changed the screen. I understand you're suggesting a flush BEFORE I do this. Is that to allow the old screen to collect more crud during the flush - then install a new, clean screen?
Again, I really appreciate your advice on this.
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Dear analogdad,
Hope you're well. Pulling the transmission pan on a '96 960 is easier than it is on a 940. On the '96 960s, the automatic transmission fluid (ATF) filler tube is secured to the transmission's casing by a single bolt. Removal of that bolt makes unnecessary any effort to separate the filler tube from the pan: never having seen/worked on a 960 tranny, I'm not sure if it is even possible to separate the filler tube from the transmission's pan (as it is on a 940's Aisin-Warner AW70-71-72 transmissions).
Further, on the '96 960, the parts diagram in Volvo VADIS - a superseded dealer parts/service database - shows that the ATF filler tube's "dipstick" has no place for fingers to grip it, allowing its removal so that fluid level can be checked. I'd guess there's a way to attach a wire to the plastic top of the dipstick, so that it can be removed.
Thus, before flushing the tranny, it might be wise: (a) to drain the transmission pan; (b) to remove the pan; (c) to remove the filter; and (d) to clean the filter and the pan.
If the filter has only a few particles of "crud" on it, then my hypothesis is wrong. There's another reason for the slippage.
If the filter is coated with "crud", then a cleaning and re-flushing is in order, using Wal-Mart ATF. If that gets rid of the slippage, then I'd drive at least 500 miles, re-inspect the filter (cleaning, if needed) and re-flush with Mobil 1 full-synthetic ATF (or other, similar ATF).
Before removing the transmission pan, spread a tarpaulin to catch the fluid that will drain from the tranny, once the pan has been removed. Kitty litter or sawdust will absorb ATF.
Hope this helps.
Yours faithfully,
Spook
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I drained and pulled the pan and found considerable sludge in the bottom - but fortunately no metal on the magnets. The filter screen was also nasty. Sent photos of it to a guy who's been in the repair biz since the early 70s and he said he'd never seen such a dirty screen before. Took it for a short test drive and all seemed good. Will drive it some more today. Fingers crossed this is it! Again, thanks for your advice on this issue.
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It hasn't happened to me, so I hesitate to suggest it, but non-magnetic sludge sounds like it originates in the friction surfaces used in the transmission. The "glue" that holds them together and binds them to the metal survives old fluid but, from what I hear, dissolves quickly in fluid contaminated with water moisture or coolant.
Your thoughts about avoiding the radiator when changing the ATF probably recall reading about how others, with failed radiators, or leaking transmission coolers (inside the radiator) have suffered ruined transmissions. I envision this could occur as a result of a mistake made flushing, where the nipple on the ATF cooler gets twisted tightening the cooler line nut, causing a crack or break internally. The larger pressure on the engine coolant side will force anti-freeze into the ATF. I'm fairly sure an oil analysis would confirm it if it isn't obvious in the drained fluid.
--
Art Benstein near Baltimore
Down in the depths of our souls, we all yearn for a job where rubber stamps are used.
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Thanks Art. Damage from coolant contamination is my big fear with this trans as I did have a leaking radiator/trans cooler last year. However, I'd think the trans fluid pumps at a much higher pressure than the cooling system and thus the trans fluid would be more likely to flow into the coolant - not the reverse. I guess I'll find out!
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Dear analogdad,
Hope you're well. About a year ago, I dismantled a replaced radiator. I detached the plastic side-tank and so exposed the automatic transmission fluid (ATF) cooler. The ATF cooler is a double-wall, foot-long copper cylinder, with a hose nipple mounted perpendicularly at each end. The hose nipples protrude through the side tank's walls. The steel ATF fluid pipes attach to those nipples.
The ATF cooler's copper wall is thick: it would be hard to twist the nipple enough to crack the copper, where a nipple joins the ATF cooler's cylindrical body. Twisting the nipple - by not holding it with a wrench, when loosening the ATF fluid pipe hex nut - would break the seal between the nipple and the inner wall of the radiator's side tank. This would cause a coolant leak, but not allow coolant to enter the ATF.
In short, this "post-mortem" suggests it will take a lot of twisting to create a crack in the in-radiator ATF cooler. If this happened, pressurized coolant could enter the ATF after engine shut-down, when the ATF no longer was being circulated by its pump, but while coolant was still pressurized, albeit not by the water pump.
Hope this helps.
Yours faithfuly,
Spook
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Hi Spook - thanks for all the advice on my transmission issue. I'm waiting for a pan gasket to arrive so I can drain transmission and see how much crud is in the pan/screen. Makes sense to to do this before going to the expense of replacing the transmission.
A few additional comments:
<> Yes, those AW 70-71 pans are a pain in the neck because the large bolt on the filler tube corrodes onto the tube and destroys it when you attempt to wrench it.
<> Nah, you just need long, skinny arms. Reach in release the spring clip, just like a 240 or 940, and pull out the dipstick.
<> unlike some AW 70-71 pans, the 960 trans has a drain plug.
I'll keep you posted on my results.
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Hi Spook - thanks for all the advice on my transmission issue. I'm waiting for a pan gasket to arrive so I can drain transmission and see how much crud is in the pan/screen. Makes sense to to do this before going to the expense of replacing the transmission.
A few additional comments:
<> Yes, those AW 70-71 pans are a pain in the neck because the large bolt on the filler tube corrodes onto the tube and destroys it when you attempt to wrench it.
<> Nah, you just need long, skinny arms. Reach in release the spring clip, just like a 240 or 940, and pull out the dipstick.
<> unlike some AW 70-71 pans, the 960 trans has a drain plug.
I'll keep you posted on my results.
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Hi Spook - thanks for all the advice on my transmission issue. I'm waiting for a pan gasket to arrive so I can drain transmission and see how much crud is in the pan/screen. Makes sense to to do this before going to the expense of replacing the transmission.
A few additional comments:
<> Yes, those AW 70-71 pans are a pain in the neck because the large bolt on the filler tube corrodes onto the tube and destroys it when you attempt to wrench it.
<> Nah, you just need long, skinny arms. Reach in release the spring clip, just like a 240 or 940, and pull out the dipstick.
<> unlike some AW 70-71 pans, the 960 trans has a drain plug.
I'll keep you posted on my results.
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Hi Spook! Analogdad, the pan on my '96 960 has a drain plug, and it is very easy to drain and remove the pan. I would change the filter as a matter of course. Volvo makes it hard to check the fluid level, my big forearms suffered nasty scrapes, so I fashioned a wire handle from a coat hanger and zip tied it to the engine. My filter wasn't dirty, but the fluid did not look good. I changed the filter and the fluid twice, but that wasn't my problem, it was the TCM, which a $45 salvaged unit cured the problem. When I buy a used car I always pull the transmission pan, looking for metal or sludge.
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Thanks Mr. Weekend. I agree - big forearms are not the best tool for getting at that dipstick!
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Dear Mr. Weekend,
Hope you're well. Draining fluid from the pan by removing the plug does not, of course, help with a dirty filter.
On the Aisin-Warner 70-71-72 transmissions used in 740s and 940s, the dipstick tube (also the fill-tube, as it extends to the top of the engine, near the oil fill-tube) is attached to the pan with a large hex nut. Removing that nut that secures the fill-tube brings a very high risk of ruining the pan. Thus, to remove the pan with the fill-tube attached, one has to take free the bolts that secure the starter motor. That's a lot of work.
On the Aisin-Warner tranmissions used in 960s (AW30-40 or 30-43), the "dipstick tube" is anchored to the transmissions casing, and so is easily detached. That, in turn, makes it easy to remove the pan and so to access the filter.
This arrangement - with a "cut-off" dipstick - reflected Volvo's view that automatic transmission fluid (ATF) would never need to be changed. How anyone could think that is far beyond me.
Thus, in order to do a flush on an AW30-40 or 30-43 unit, one needs a length of tubing to insert into the "fill tube", into which tubing a funnel can be inserted.
I note your comment as to having made an ATF dipstick handle from coat hanger wire. That's a low-cost, effective solution, always a good thing!!!
Hope this helps.
Yours faithfully,
Spook
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Speaking from experience with my 1995 960, the hollow square top of the yellow plastic ATF dipstick has been designed to accept a ½ inch drive extension while the flange interacts with the spring retaining clip on the dipstick tube. With each alternate quarter turn, the clip is either released allowing the dipstick to be withdrawn, for inspection, by the extension or other means or engaged locking the dipstick in place and allowing the extension, if used, to be easily pulled off.
Hope this helps.
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I would pull the pan and change the filter and fill up with new trans oil.
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Thanks for responding. I neglected to mention that the transmission was flushed and refilled with synthetic fluid less than 6 months/3000 miles ago. Any other ideas?
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No need to pull the pan,disconnect the return line coming out of the radiator,,stick a hose on & let 2 qts come out to a antifreeze bottel,fill 2 qts,run again fill 2 & flush the entire contents
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Thanks for your response. Good idea - I've used this procedure on other RWD Volvos - even have the IPD drain hose for 240s. Re. this particular car, see my response to previous post.
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