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Topic: Autobox won't move up from 2nd (Read 446 times) |
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Dixon
Newbie
1997 2.9 12v Ultima
Posts: 10
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Autobox won't move up from 2nd
« on: Nov 24th, 2005, 3:07pm » |
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Hi, all. After running five-door Mk3s I've finally graduated to proper Scorpio (lovely!) and immediately hit an autobox problem.
The car is a 1995 2.0 16v Exec Special Edition (full Ultima spec except no headlamp washers as far as I can see) with 98k on the clock.
The box won't shift up from second once it's warm. When first started from cold it will reluctantly move into 3 only if you take foot off accelerator, but once warm it stays in 2nd, but you can feel it hunting for 3rd without success. Then the _overdrive off_ light starts flashing.
Ex-Ford mechanic advises the solenoids have gone, but says could be other probs once he gets in there to change them so advises to change whole box, maybe for a used one.
Reading these posts makes me wonder if that's all there is, or if there could be another fix? Does anyone know of this particular problem? Autobox oil is NOT bright red, more towards brown, smells a little odd (posibly the burnt smell that's mentioned on this site, but not sure) but there are no black bits. Another post mentions that this could indicate it's the original oil.
Don't want to replace box if it just needs oil change, but don't want to replace oil if it'll still need the box replacing.
I've read over and over again all the relevant help pages/fault finders on this excellent site but still can't find exactly match to these problems (although starting to learn towards accepting it's a dead autobox  ). So suggestions would be most gratefully received, if anyone else has encountered this behaviour.
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Snoopy
Administrator
Very old.BAD tempered and missing friends.
Posts: 6278
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Re: Autobox won't move up from 2nd
« Reply #1 on: Nov 25th, 2005, 7:35am » |
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I do think that your gearbox is failing from the syptoms that you describe. Maybe your best course of action is to get a 'good' second hand one as your ex-ford mechanic advises.
repairing an old box can be an expensive option although the solinoid tray can be replaced on its own.
as can a single solenoid AFAIK
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Dixon
Newbie
1997 2.9 12v Ultima
Posts: 10
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Re: Autobox won't move up from 2nd
« Reply #2 on: Nov 25th, 2005, 8:31pm » |
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Hi All - Weird one here - anyone have an explanation for this new development?
Drove the car into town - about four miles, enough to warm up - and as expected no 3rd gear or O/drive, and the "O/Drive off" dash light starts flashing after a mile or so.
Park up, leave car for maybe 20 mins, start up and head for home... and realise the gearbox is behaving absolutely as it should! 3rd gear's there, get to a fast strip of road, up to 50, and yes O/drive's engaged. And that o/drive light's not flashing anymore. Slow down for roundabout, drops to 2nd, then off down fast road, up to 3rd, then o/drive and back to 60! (er, country area, so some de-restricted strips, honest, officer.)
I was both thrilled and baffled (as the actress said, etc, etc). Pulled over, did a U-turn and went back over same route - and d**n gearbox returns to being naughty, refusing to change up out of 2nd.
Anyone have the faintest clue what's a happening here? I'm still baffled, and I can't find any reference on any page here remotely describing this doesn't work/work/doesn't work again behaviour.
Saw the page about Engtine Wiring Loom problems so I'm now wondering if it's actually an intermittant electric fault. Will check in daylight tomorrow, but meantime can anyone tell me if this kills the dead solenoid/get a new gearbox theory?
Will want to change the oil in any event, but does this sound like the gearbox might not need replacing after all?
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Eric_R
Administrator
Cosworth Owner 1998 - 2006 & site co-founder
Posts: 1792
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Re: Autobox won't move up from 2nd
« Reply #3 on: Nov 25th, 2005, 10:43pm » |
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Dixon,
Once the EECV control module detects a fault with the gearbox, it sets the OD light to flash and then locks out the gears where it detects the problem. the PCM is constantly checking the performance of the autobox, and if it detects no faults then it allows all the gears to function, just like it did on that journey.
The autobox does not control its performance at all, the control is all in the EECV PCM, so if the EECV thinks there's a problem with the hardware it will shut down the gears effected. It could be a wiring fault but these have been very rare. It's more likely to be failing solenoids/brake bands or a problem with a sensor inside the autobox, the VSS, the OSS or the TFT sensors.
Is your speedo working okay? The VSS sends the speed signal and this can cause errors with gear selection.
Your best bet is to have the EECV read with an OBD lead and check for the DTCs, clear them, run it again until the OD light flashes, and then check the DTCs again. If they are the same then it not likely to be a loom problem but a hardware fault inside the autobox.
Perhaps if you post the area you live in another owner could read the DTCs for you.
HTH
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Dixon
Newbie
1997 2.9 12v Ultima
Posts: 10
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Re: Autobox won't move up from 2nd
« Reply #4 on: Nov 25th, 2005, 11:56pm » |
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Hi Eric and thanks for info. Yes, the sppedo is working fine as far as I can tell. But this is now getting weirder and weirder (at least to me).
Just popped out for a last minute appointment at Dr. Guinness' surgery. Car frozen over at first, so four or five minute wait with engine running to clear windscreen, etc., then off to see the Doc.
Five minute drive (all below 35mph) and the girl's still stubborn in second [should be a movie title, that].
Twenty mins later, out again, same route home, and Whoa! There's 3rd, then there's O/drive as well. Carry on further this time into de-restricted 60/70 zone, and the girl gallops, staying in O/D. Slow down and she shifts down - speed up, and she shifts up, perfect behaviour. After mile and a half, get to roundabout & turn round, and she's back to her stubborn second behaviour.
So this evening it's bad when cold, good when warm - there's simply no consistency here.
Will have to do a crash course now on all the abbreviations you use before I can understand your last post (D'oh, d**n newbies!).
I'm in North-East Hampshire - Alton to be precise - if there's anyone local who has any great ideas!?!
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Eric_R
Administrator
Cosworth Owner 1998 - 2006 & site co-founder
Posts: 1792
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Re: Autobox won't move up from 2nd
« Reply #5 on: Nov 26th, 2005, 11:32pm » |
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Dixon,
This symptom, of running okay when warm may be an intermittent fault with a sensor. There are three sensors in the autobox - there's the VSS - Vehicle Speed Sensor that sends a pulse dependant on the vehicle speed, the TSS - Transmission Speed Sensor mounted on the internal planet carrier to detect shaft speed, and the TFT - the Transmission Fluid Temperature sensor. In the case of the TFT and the TSS (sometimes called the OSS) if they are working intermitently then the EECV will lock out the top two gears to prevent damage, so it could be them. It's unlikely to be the VSS if your speedo is working correctly.
see http://www.fordscorpio.co.uk/ccmonitor.htm
However, it could also be a fault with the C and D solenoids, or the main line pressure solenoid, although when they start to fail there's more often a rise in RPM and then a thump as a gear engages, and you wouldn't expect the autobox to behave faultlessly in between times as yours does if the drive bands or solenoids are faulty.
I would recommend an OBD check with someone near you to download the DTCs and see what the reported DTCs are. If they are rational (ie related to faults you would expect) then go with them. If they are many and varied, note what they are and then clear them, run the car again and check for the DTCs again and make sure they are exactly the same - if they are not then you might suspect a wiring loom fault. Your care is a pre-June 96 one with Arnitel wiring so it is possible, but very rare.
Any OBD owner in the Alton area can oblige with a quick reading for Dixon?
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