Tiptronic Reverse slips on acceleration

[DWHail]

Hi,
I have had an intermittent slipping problem for over 12 months with the reverse gear on my 2000 1.9 TDi Passat tiptronic.

I have just clocked 100k so I have changed fluid and strainer. I cleaned the magnets which had really fine particles stuck to them. Much smoother changing and more consistent operation now.

My reverse problem now is also consistent.

At tick over, 850rpm, the car creeps back. As soon as I press the accelerator it slips and stops moving, I can feel it 'let go'. If I take my foot off the accelerator the car starts moving backwards again after a couple of seconds.

The gearbox is a ZF5HP code ERY.

Any suggestions please?

[DWHail]

Here is an interesting thing: I changed the fluid and strainer; out Sunday, left overnight then refilled Monday 6th Oct. I's now 9th Oct and the reverse gear is actually improving.
Last night I went to a quiet car park and reversed several times about 50yds each time. There is definitely a better response and it is getting better.
Could this be a flushing effect? Or just my wishful thinking.
Would it be worthwhile draining and replacing the ATF in a week or so?

[Sam]

The two easy first steps are to check the ATF levels, which you've done and scan the transmission control module (TCM) for error codes using VCDS, which I'm not sure if you've done.

Not to doubt or even question your skills but how are you checking the ATF levels? IIRC it has to be done at temperature using all sorts of witchcraft. Some prefer to remove the pan and start a fresh, giving them a chance to examine the components at the time. From your description it sounds as though you know what you're doing though.

There are a few reports of the reverse clutch drum failing (which may explain the metallic particles on the magnets) and having to get a gearbox specialist involved to replace it but, thanks to the internets there are detailed videos on Youtube documenting the process. Again this depends how handy you are with a spanner.

My advice, for what it's worth, scan for fault codes first. If you've got none that relate to the gearbox and you have time and skills, drop the pan and inspect components.

Have a watch of this which explains what I was trying to say in far fewer words - ZF 5HP19 D/G clutch drum (reverse drum) - YouTube

[DWHail]

That is an amazing help. Thanks. I don't have VCDS but I know a man who does. I will get that done.
If I drop off the pan again and remove the valve body will I be able to visually check the reverse band from there? I am uncertain that it is damaged as the stuff on the magnets was extremely fine, almost like a paste. There were no pieces of metal at all. The photo I took is to big a file to upload.

I don't mind a challenge and as I am retired time isn't a problem.
I have no idea where to get the parts but I will cross that bridge when I come to it.

Thanks again for your invaluable help.
Dave

[DWHail]

https://onedrive.live.com/redir?resi...nt=photo%2cJPG

Hope this works. Should be photo of gearbox pan.

[Sam]

The dirt on the magnets looks normal to me (but I'm not a mechanic!), iron particles, clutch dust and dirt.

The same chap in the video above has another one showing the valve body removal process > ZF 5HP19 Valve body removal - YouTube.

Towards the end around the 8m50 mark you can see through to the drums, whether that's enough room for you to check for damage or not, I'm not sure.

Another excellent resource is taligentx from the american ClubB5/PassatWorld site. He has his own site here > taligentx.com: Passat - ATF & Filter Replacement < which again says more than I could ever say.

[DWHail]

The tailgentx.com link is what I used when I took the pan off. The whole site is excellent.
What you say about the stuff on the magnets is what I thought. Actually the fate of the gearbox was dependant on that.
I am keen to do a second ATF change so as to complete the flush process so I will drop the pan and valve assembly and post back in a couple of weeks.
I will be wearing toe techtors when doing mine though. The thought of the guy in the video dropping something makes me cringe!

Again thanks for your help.
Dave

[DWHail]

I have just finished changing the ATF again. I was surprised at the sludge after just 300 miles.

The forward gears are smooth as silk but the reverse isn't right. Though there is improvement, it is not as it should be.

I am taking the caravan to Scotland this weekend and when I get back I am going to remove the gearbox and replace the 'D' drum.

Is there anywhere in Britain I can get one? It is £40 postage from USA.

This appears to be the required part. http://www.ebay.co.uk/itm/1909538637...%3AMEBIDX%3AIT

Any tips on removing the gearbox would be appreciated.

Thanks in anticipation. Dave

[DWHail]

Here is some useful info if anyone is contemplating changing their D drum.

DIY- How to replace reverse drum, ZF5HP19 - E46Fanatics

Its a BMW but the ZF box is similar.

[DWHail]

Just got back from having diagnostics done and there are No Faults on transmission.

I seem to be struggling a little with sourcing parts.

I need to take off the pan and valve body to see if mine is bolt in or not and inspect the drum.
I have asked here in UK but can only find OEM parts, I can't find an 'upgraded' version. Some USA suppliers on E bay do them but I need to be sure what I am ordering.
Any recommendations?
Will I need to remove the oil supply and return tubes before lifting the oil pump out?
Is the diff oil separate? If so I can change that whilst it is off.
Is it worth doing the torque convertor oil?