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Autobox not disengaging.

Posted: Sun Nov 08, 2009 10:58 am
by thedogsbollox
Ok so I understand the autobox not going into top gear when cold but the last couple of days I have had a problem where, when I start from cold and go to the end of my street, I brake and the motor keeps pushing me. It trys to stall also, I thought I was back in a manual and actually went for the clutch. Is this also due to the cold or do I have a problem?

Re: Autobox not disengaging.

Posted: Sun Nov 08, 2009 11:55 am
by mikeonb4c
thedogsbollox wrote:Ok so I understand the autobox not going into top gear when cold but the last couple of days I have had a problem where, when I start from cold and go to the end of my street, I brake and the motor keeps pushing me. It trys to stall also, I thought I was back in a manual and actually went for the clutch. Is this also due to the cold or do I have a problem?
That doesn't sounds right to me. Some 'creep' yes, but serious pushing sounds wrong. Have you done the usual checks on ATF fluid to see if level is OK (must be checked after decent drive, warmed, and with engine running and in gear I think) and colour and smell are normal? Hve you done owt with the gearbox lately? What RPM is engine ticking over at when cold? I'm not a techie I fear but others will no doubt comment.

Good luck - keep us posted 8)

Re: Autobox not disengaging.

Posted: Sun Nov 08, 2009 1:17 pm
by francophile1947
Definitely not normal :(
Hopefully Dandy will be along with an explanation - auto boxes are a total mystery to me :oops:

Re: Autobox not disengaging.

Posted: Sun Nov 08, 2009 1:29 pm
by dandywarhol
When it happens again, quickly knock it into neutral and see if the revs are "hanging up" Could be a problem with the fuel pump high idle system staying on too long - its operated by vacuum from the brake servo pump via the actuator next to the EGR actuator and triggered by the coolant temp switch in the middle of the head (which also controls the autobox warm up system)

Re: Autobox not disengaging.

Posted: Sun Nov 08, 2009 1:31 pm
by scanner
For the "pushing" to continue the engine must still be revving and that is the cause. The box will continue to provide "push" only as long as it is being "pushed" by the engine.

It sounds like that for some reason your throttle is sticking and the engine is carrying on revving even after you've taken your foot off the pedal.

Edit..
There you are DWH has offered one possible solution.

Re: Autobox not disengaging.

Posted: Sun Nov 08, 2009 1:36 pm
by nfn
I had exactly these symptoms on an automatic trans pick-up truck. It was due to a malfunctioning torque converter -- which acts sort of like the clutch would in a manual car. The torque converter had to be replaced. The mechanic first checked for more common and cheaper to fix faults (e.g., solenoid faults), but in my case the whole thing needed replacing. If the problem continues you may need to locate an auto trans specialist.

Re: Autobox not disengaging.

Posted: Sun Nov 08, 2009 2:38 pm
by thedogsbollox
Actually that is the least of my worries. I am once again stationary at the side of a motorway. The engine has gone pop.

Re: Autobox not disengaging.

Posted: Sun Nov 08, 2009 3:22 pm
by westonwarrior
:(
hope all is well

Re: Autobox not disengaging.

Posted: Sun Nov 08, 2009 3:34 pm
by missfixit70

Re: Autobox not disengaging.

Posted: Sun Nov 08, 2009 6:06 pm
by thedogsbollox
Back to the gearbag. I noticed summit else this morning before I read your replies. Oh yeah it done it this morning BTW and stalled. When I got going again it seemed to go up the gears really quick. When I tried to floor it, it never kicked down. When warm it behaves normally.

Re: Autobox not disengaging.

Posted: Sun Nov 08, 2009 7:17 pm
by nfn
Sounds more and more like the torque converter is giving problems -- but I guess it doesn't matter if the engine popped...

Re: Autobox not disengaging.

Posted: Sun Nov 08, 2009 9:38 pm
by missfixit70
Could it be as simple as manky or low oil in the 'box?

Re: Autobox not disengaging.

Posted: Thu Nov 12, 2009 2:29 pm
by Alex86
My Gearbox does exactly the same! only when cold??? i have to pop in to "N" at every junction until its warmed up then its fine for the rest of the day! it only started after i had atf changed in the summer. since then the oil has been again but its still the same. I've left it for a couple of months because of money(lack of) but hope to get it sorted before Christmas!

I'll let you know if i have any development.

Alex

Re: Autobox not disengaging.

Posted: Thu Nov 12, 2009 3:50 pm
by nfn
Alex86, one thing you could check that's free is for transmission fault codes stored in the computer. There's a fact sheet in the members area on how to do this using a piece of wire. Maybe a shift solenoid is malfunctioning while cold?

Re: Autobox not disengaging.

Posted: Thu Nov 12, 2009 4:10 pm
by thedogsbollox
Alex86 wrote:My Gearbox does exactly the same! only when cold??? i have to pop in to "N" at every junction until its warmed up then its fine for the rest of the day! it only started after i had atf changed in the summer. since then the oil has been again but its still the same. I've left it for a couple of months because of money(lack of) but hope to get it sorted before Christmas!

I'll let you know if i have any development.

Alex
Thanks alex
will also post the solution to my problems when I discover what it is too.