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        General >> Problems >> Autobox dropping into first gear
        
(Message started by: roger_howes on Mar 26^th, 2010, 2:49pm)

Title: Autobox dropping into first gear
Post by roger_howes on Mar 26^th, 2010, 2:49pm

Hello all,

I have an intermittent problem on my 1997 Cossie autobox. The first time it happened was just over a year ago. I was travelling at a steady 70 on the A14 when it felt as if I had lost drive. It happened suddenly with no warning. After limping to a layby, it turned out that it had actually gone into first gear. I tried moving off again - same problem. The AA got me home.

I thought that the next morning it was car scrappage time (£800-£1000 for a recon box)! But no, the box seemed OK.

It did not happen again until about a month ago, then, exactly the same problem, but this time at lower speed. It then happened again a fortnight ago, again at about 70mph.

I tried to keep it out of first by pressing the Winter button - no good. I then moved the gear lever to '2', and that did it. However, as I reached approx 50mph, the gearbox changed up as usual even though it was still in 2! Obviously it shouldn't have done. After some minutes it started to think better of it and kept changing between 3rd and 2nd. Eventually the fault cleared and it stayed in 2nd. I then moved the lever to 'D' and it behaved OK the rest of the way home.

I took it to the local autobox garage a week or two after and they checked for fault codes, but if there were any they were lost, as in the meantime I had been on holiday and the battery had gone totally flat standing in the driveway. He checked everything and then took it for a 40 minute drive but could not get the fault to reoccur. I have not been able to since, either.

When the fault is not there the box behaves perfectly.

He doesn't think it's the box and made a guess at the selector switch sending out the wrong voltage, but obviously he wasn't sure.

Can anyone throw any light on this? Be great if you could as I can' trust the car at the moment. I get nervous overtaking!

Many thanks.

Roger.

Title: Re: Autobox dropping into first gear
Post by tonyboy on Mar 26^th, 2010, 5:27pm

If it's not a 12V , clean the MAF that seems to be the broblem of a lot of gearbox problems....... http://www.fordscorpio.co.uk/cleanmaf.htm ..... hth

Title: Re: Autobox dropping into first gear
Post by Snoopy on Mar 26^th, 2010, 5:50pm

Also does the speedo behave oddly if so it could be the VSS as the EEC reads the speed from that and calculates the gearbox changes.

It could also be something as simple as a blocked oil way. in the gallery of the box.

Have you checked the levels lately?

What is the condition of the oil in the gearbox?

if all else fails could be worth doing an oil and filter change on the box.

Other will have more advice I am sure.......

Title: Re: Autobox dropping into first gear
Post by Mike Holmes on Mar 27^th, 2010, 1:17pm

Did you get "O/D" flashing at any point?

Title: Re: Autobox dropping into first gear
Post by roger_howes on Mar 30^th, 2010, 7:57am

Thanks for your replies.

The engine and gearbox perform perfectly until the fault occurs (without warning). If the MAF sensor was at fault would this not show itself in other ways?? Don't know - can anyone advise?

The garage checked everything, but did not change the fluid or filter. Speedo showed nothing untoward when the fault occurred. Regards the speed sensor, even when the fault seemed to still be present and I had locked the g/box in 2nd, the box still changed up to 3rd at 50mph (until the fault cleared)! This seems to suggest the speed sensor was OK - or is this an invalid assumption? All the same, I think a fluid and filter change would be worth doing. I've been told the price of a filter is horrendous!

Didn't notice whether the OD light was on. I was mostly concerned about the fault red-lining the engine and traffic up my backside! I still haven't managed to get the fault to reoccur. When (if) it does I will look for the OD light. If it's on, what would this tell me?

Many thanks.

Roger.

Title: Re: Autobox dropping into first gear
Post by tlundkvi on Mar 30^th, 2010, 8:22am

on 03/30/10 at 07:57:27, roger_howes wrote:

Regards the speed sensor, even when the fault seemed to still be present and I had locked the g/box in 2nd, the box still changed up to 3rd at 50mph (until the fault cleared)! This seems to suggest the speed sensor was OK - or is this an invalid assumption? All the same, I think a fluid and filter change would be worth doing. I've been told the price of a filter is horrendous!

If your speed reading was OK, it can be something else. But the gearbox has a fallback program it reverts to if the VSS is offline for a while, otherwise it wouldn't switch. The gearchanges are quite harsch in this mode also compared to the normal.

The price of the filter and gasket OEM is not bad http://www.fordpartsuk.com/shop/scorpio_auto_box_gasketscreen_filter_and_seal_kit_1343.htm

A 3rd party kit is around half of that.

Title: Re: Autobox dropping into first gear
Post by Mike Holmes on Mar 30^th, 2010, 9:44am

This is for the autobox fluid and filter? Had mine done couple of years ago, don't remember the filter being hugely expensive. Then again it wasn't "a garage" that did the job. ;D

NB for a fault the "O/D" light doesn't just come on, it flashes. None of these dashboard warning lights are very bright I agree, if you have your lights on in daylight they're dimmed so you can hardly see 'em.

Note also there's lots of stories on this forum of guys spending huge amounts of money fixing an autobox that isn't actually faulty, it's the PCM (computer) messing about with it trying to make its various input readings add up properly. I also cleaned my MAF but still not sure it's right, hence just got a new one from BuyPartsBy. Only £53. They can get tired and worn out and as it's almost certainly original that makes it 15 years old. ;D

Title: Re: Autobox dropping into first gear
Post by tlundkvi on Mar 30^th, 2010, 10:05am

Fluid is around 5-6 pounds per liter, you need up to 8.5l

Spec says Mercon V (A4LDE as of 97 when Mercon V was invented), but you can use Dexron III + Lubegard Mercon V additive (a tenner). Some put plain Dexron III without problems reported.

Title: Re: Autobox dropping into first gear
Post by Dave2302 on Mar 31^st, 2010, 1:27pm

From what you have described I would say your tranny man is spot on, the selector position switch is going duff, happens more so in damp / wet / icy conditions.

Get it changed by the transmission man, not a general garage (as most won't set it right), otherwise it will shag your gearbox and or engine very quickly

HTH Dave

Title: Re: Autobox dropping into first gear
Post by roger_howes on Apr 4^th, 2010, 9:46am

Hello all.

Thanks again for your replies. The suggestions for affordable fluid filters was particularly welcome. Thanks tlundkvi for the link, I thought prices there were very reasonable.

Dave2302 - re your comments about when the fault occurs, the first time it happened was in very wet weather when I hd been travelling for some time at speed in heavy rain. The subsequent times the weather was cold. The autobox man quoted me £75 for the selector switch and £35 for fixing it - plus VAT of course! Doesn't sound too bad to me.

In the meantime I still can't get the problem to return and I really need that fault code (if there's one to be had)!

Thanks.

Roger.

Title: Re: Autobox dropping into first gear
Post by Dave2302 on Apr 5^th, 2010, 5:01pm

Roger,

This really does sound like the selector position switch,
they don't usually show a code, because what it is doing is telling the ECU that the selector has moved to a different gear.

They are known to be very trublesome in the autobox trade and what yr man is quoting you is the correct price for the switch and I assume around an hours labour.....a good price as they can be a booger to fit lol.

Cheers Dave

Title: Re: Autobox dropping into first gear
Post by roger_howes on Apr 8^th, 2010, 9:51am

Many thanks Dave.

I keep running the car, but no fault, but then it's been dry and not really cold.

I'll keep trying (especially when it's wet), but if it doesn't reoccur I must decide whether to take the plunge and have it done anyway.

Thanks again, I'll keep you posted.

Regards.

Roger.

Title: Re: Autobox dropping into first gear
Post by Highlander on Apr 8^th, 2010, 10:32am

I had a similar problem in a 24v Roger.

First showed itself in pouring rain, lost drive completely for a few seconds,

Next stage was no drive in first gear occasionally, to pull away i had to select 2nd then once up to speed put it into D

then it lost 1st gear completely.

I drove it for months like that before it lost all drive :)

New switch sorted it

Title: Re: Autobox dropping into first gear
Post by Mike Holmes on Apr 8^th, 2010, 1:03pm

Interesting ~ simple as that

Re Roger's original problem, has this been sorted yet?

Title: Re: Autobox dropping into first gear
Post by roger_howes on Apr 14^th, 2010, 8:58am

Thanks Highlander, that's interesting. It seems to reinforce the suggestion that my problem is the selector switch.

I still haven't managed to get it to go wrong again. I wonder if I'll have to wait until next winter?

But perhaps, if I wait for a wet day and then charge up and down the A50, it might reappear!

I'll keep you posted.

Many thanks.

Roger.