Polo mk4 gearbox and cold running

[Iceash]

As the mornings are getting colder I have started to notice that when changing from 1st to 2nd I get a slight chattering sound from the box. Sometimes you can't hear it but can feel it through the gear knob. I have a few questions for the experts out there

Do you think this is doing damage?

would adding anything like slick 50 help?

Is this a sign that the gearbox is old and there is nothing to worry about?

When the box warms up, she is lovely to drive smooth every time. She is a Mk4 polo 1.4 R reg, done 81000 miles.

All comments welcome and appreciated.

Thanks,

Iceash

[davejw]

Until the oil warms up, I guess there will be loads of boxes out there that are none too happy with the cold weather. I'd just warm up gently, make sure you change gear slowly (don't try to beat the synchro) and live with it. Slick50 sounds like a good idea in theory but if it makes the oil too slippery you will damage your synchro's as they need a bit of friction to work.

By the way, check on the Ferrari forum, most of the 80's cars wouldn't even go into second until the gearbox was warm!

Cheers,

Dave.

[Iceash]

Cool, so in theory your saying I have a Ferrari I like it. So this isn't an uncommon thing then?

Thanks for the reply,

Ash

[Iceash]

I've bought Molyslip. is that any better?

[Pigeon]

I doubt it will make any difference, indeed it might make it worse. The gearbox is balky because of the cold oil being more viscous and creating more drag on the moving parts; it's nothing to do with actual friction between sliding surfaces. Where you do get friction between sliding surfaces is in the synchro cones, and you don't want to get rid of that

Double-declutching is the thing. Into neutral, clutch up/match revs, clutch down again, into second, clutch up.

[GavinPearson]

If the synchros work warm then the issue is that oil isn't displaced by the synchro cone as pressure is put on it and therefore it cannot get the gear to the same speed as the synchro hub.

In the industry we do oil compatability tests to make sure that additive packs don't cause problems.

Sometimes when enough people do the mod and run without problems then you could say it's a statistically safe bet, however, my advice is that very often the best solution comes from the manufacturer, so get oil from your dealer.

Our Turbo Beetle ran with no problems in 3 Farenheit (-20 Celcius ish) on standard VW oil.

OEM oil tends to have a special formulation, but I would advise changing the oil in there right now for OEM oil, it may be expensive, but it will probably cure the problem.

What you find is that as the additive pack ages it becomes less effective, and in the case of a synchromesh gearbox it results in some baulking when cold.

[Iceash]

Hi Gavin, Thanks for the reply.

I have changed the oil to one of the VW approved oils so my garage tells me anyway lol. I have also added the molyslip as well. the both seem to have helped a little but not completly. Could it be something I'm doing. Only been driving the last 8 months, plus also my last car did this, one of the reasons I sold it! any ideas would be great m8.

Thanks,

Iceash

[Iceash]

I've been reading up on VW and there gearboxes, it seems that they are not a smooth box? would any one else agree with this? The last thing I want to do is get the box rebuilt to find it is no better. All the help I can get will be great.

Thanks,

Ash

[GavinPearson]

The molyslip may be preventing the synchro action from working properly.

It interferes with the additive pack in the oil that makes the synchromesh work.

I'd drain and refill.

[Iceash]

So far I've noticed improvement in the cold mornings. And when warmed up it does seem a lot better. I just asked the question because if you check a lot of the VW forums you seem to run across a lot of crunchy gearboxes. Especially when cold! Just wondered if it was down to poor design?

Thanks,

Ash

[GavinPearson]

Design is fine, but they are matched to a lubricant.

Use the OEM lubricant in the VW bottle and all is good.

Use A.N.Other brand and it won't work as well.