Auto Reluctant To Go Into Drive

[ric220]

Well, sods law. I decide to sell my aging sharan 1.8t automatic and it develops a new problem! In the mornings it won't shift from park to drive. The solenoid prevents it and there's no click from the box when I put my foot on the brake which releases the switch that locks the lever. I know this problem is often linked to dodgy wiring in the tailgate which stops the brake lights from working, but I've meticulously replaced the wiring and I'm pretty confident it's ok. What's strange is that once the car (and weather) have warmed up its generally fine for the rest of the day. Any ideas? Cheers

[BrianH]

It may be worth scanning the gearbox using vcds, it might also be worth checking the fluid (quantity and condition) if you haven't already. The brake light switch is also known to fail in strange manners which may not cause it to stop noticibly working, but will log errors in vcds (would also cause the glow plug light to flash on the diesel versions, not sure its a visible fault on the petrol versions).

[ric220]

Thanks Brian. Would low gearbox oil prevent selecting drive when it's cold?

[BrianH]

Its possible . Won't cost anything to check either. A scan with vcds should allow you to rule out the brake switch for sure.

[ric220]

Ok cheers - I'll get that done asap.

[ric220]

I'm going to get my mechanic to change the gearbox oil next week. Can I just check is one change enough? I've read that on some cars you need to change it 2 or 3 times to ensure all the old oils gone. Also, is there a filter? Thanks all.

[BrianH]

it depends how bad it is - any new fluid mixed with the old stuff will help to some degree if its in a poor condition, but you can't drain all of it out all at once as some remains in the touque convertor (this is the case for all auto boxes as far as i know - the converter is a large donut shape which is only open round the centre, so anything below the middle of it won't come out).

 

Not sure on the filter though i think theres info on changing the fluid in the faq section (and the checking procedure as well).

[ric220]

Thanks as always Brian. I'll check out the faq and go from there.

[chrispb123456]

The four and five speed auto has filters but only the four speed is possible to change after removing sump, the filter on the five speed is buried and requires dismantling to remove

[ric220]

Thanks. Unfortunately mines a 4 speed (4000rpm at 80mph gets tiring after a while).

[BrianH]

I'd still be inclined to see if you can get a vcds scan on the box and engine if you have the option (the basic cable which will suit what you need isn't particually expensive, and the lite version of vcds will be adequate to do whats needed)