VR6 Auto Box issues

[alexvr6storm 10]

In the last week it seems as though my auto box is stuck in sport mode. It will only change up through the gears when i boot it, if i drive quietly it is very reluctant to move through the gears. Anyone had these issues? It had the fluid changed last November, am i right in thinking there is a control unit separate from the ecu?

Any ideas appreciated.

[tbvr6 0]

Having some fun and games with my auto box too, but not as you describe. It is my understanding that the auto gearbox has its own ECU. Some people have suggested changing fluid and resetting auto ECU to basic settings can help. The ECU is designed to learn from your driving style and other conditions, but this process can go wrong, hence resetting back to basic. Please note that is not my own knowledge, but what I have picked up from various forums, so might be hokum!

 

I am told by my mechanic that a common problem is the multi-connection sensor/switch which you will see at the back of the auto box. Try removing the electrical multi-plug and cleaning it. Bit of a pain to get the connector out as it will be very stiff. It has clips top and bottom of plug, but can still be very stiff. Had to help mine out a tad with a flat blade.

 

However, I replaced my one of those and it did not help fix my problems, but might be worth a try on yours.

 

Also check the speed sensor connections are ok. If the gearbox is getting bad speed information, that can effect shifting.

[fla 9]

scan it for fault codes if you can. Alex where in London are you based? I am in NW and have got VAGCOM if needed. Might just need clearing and resetting.

 

tbvr6 you're correct the auto ecu piggybacks on the engine ecu and 'learns' your driving style wrt gear changes.

[alexvr6storm 10]

Cheers guys, guess it's time for VAGCOM. fla i am in West London but the car is currently at my parents in Norwich as i was up there last week when the problem started so i decided to leave it there. Will get it back down soon and would be up for a vagcom session!

[tbvr6 0]

Had mine scanned and came back with a result "Improbable Engine Speed sensor signal", but still have not got to the bottom of why. Although my symptoms are different to yours, may be a similar cause.

 

For comparison, my symptoms are that if the gearbox shifts gear in a tight bend, it gets stuck on high revs and no speed. I have to switch ignition off/on to reset to normal operation.

[Stonejag 10]

Just to doublecheck, does it chug a little when you come off the throttle? Mine behaved similarly to how you describe when one of the MAF wires snapped, it felt like a gearbox problem but actually the engine was just down on power...

 

I'm not a million miles from you and also have Vagcom if you need a second look. I've never had an electrical problem with the gearbox (touch wood) - mine have all been related to low fluid, so check that first. Flushing it makes a huge difference if it's a bit tired and well worth it for 30 quid's worth of ATF and a couple of hours!

 

Stone

[alexvr6storm 10]

Now you mention it Stone it does chug a little bit when coming off the power, it seems to always be looking to change down but reluctant to change up now matter how i am driving it. My mate who i bought it off said he had a few problems last year but when the fluid was changed back in November it was fine. I have had it since January and it's done under 2000 miles since then and it's been all good until last week, how long is ATF supposed to be god for?

[Stonejag 10]

It's not on the service schedule so I'm impressed it's been done! Check the dipstick with the engine running and ATF temperature at approximately 70 degrees (ask Vagcom, it's in measuring block 3 of the auto ECU if memory serves). If you see nothing on the dipstick then it definitely needs doing - mine was almost empty when i bought it. It should be slightly gloopy (thicker than engine oil) and a transparent red colour - mine was more like chocolate milk when I did it, looked awful! Any colour not reminiscent of Tizer, change it! If there's none on the dipstick, check with the engine off - the fluid level will rise as some of the torque converter contents drain back into the sump. Over time you'll lose a little - but much more quickly if something is close to failure and overheating it. The stock gearbox cooler is frankly **** (manufacturers recommend it should ever really go above 85, so who decided to warm it up with 110-degree coolant?!) so I've replaced mine with a small Mocal in front of the radiator - as a side benefit you can then use hose kits designed for a manual...

 

There's a pictorial guide here: http://www.deylan.co.uk/golf/096%20Fluid%20Change/index.htm

 

Basically the procedure is, massive heavy sump guard off (4 bolts), plate of wood on a jack supporting the sump, remove the four sump bolts and drop the jack. Let it sit and drain for five minutes (you can loosen the 2 pan filter bolts to get another couple of litres out) then safely dispose of the fluid. Clean the pan of sludge and metal shavings, then refit it and top up. Run the engine and immediately check the level, topping up if required. Work the shifter through all the positions a few times while idling, then go for a drive for 5-10 minutes to warm up the fluid you just poured in. When you're back, do it all again but this time replacing the filter element and pan gasket as well. Then refill and it'll be castle improved :) The reason for doing it twice is to flush out the fluid in the torque converter as it holds a couple of litres where it can't drain into the pan. If you have time it'd be an excellent idea to drill and tap a hole in the sump to accept a standard drain plug - just make sure it'll fit under the sump guard plate. Also note your pan may not have a magnet in it - mine didn't and if you'd seen the size of the tiny channels in the valve body you'd realise why it's such a good isea to add one :)

 

Don't do it on a windy day and stay in a garage if possible (to avoid dust etc getting into your valve body which would be very bad). You should notice a huge difference, especially if the level was low - no more feeling like you're revving in neutral at junctions any more! I check mine whenever I'm doing the engine oil, it's a good habit to get into. Given how little ATF costs compared to a gearbox rebuild I'd just do it anyway.

 

Stone

 

---------- Post added at 3:18 PM ---------- Previous post was at 3:14 PM ----------

 

Also I think the 'adjusts to your driving style' thing is a marketing myth - the Bentley has a table of shifting speeds and mine's spot on. I'd love 3-4 to have been 29 instead of 32, it can't make its mind up if you get stuck behind someone driving a bit less confidently...;)

[alexvr6storm 10]

I think he only had it done because he was having issues with the auto box, that said I have all the history for the car from the original bill of sale and there is no reference of it ever having been done before. Had full VAG history up to 50k and has now done 90k. Would VW have changed it in the first 50k as part of the servicing plan do you reckon? I checked the ATF level when I got it and again last week when it started playing up, definitely not low, but I would say it is a dirty dark red from memory. Think i will see what VAGCOM has to say first and then change it depending, can't believe it needs doing again after 7 months and under 2k of driving :( Thanks for you advice mate, much appreciated.

[Stonejag 10]

VW consider the gearbox 'sealed for life', so it won't have been done before...the reason is the box will outlast their factory 60,000 mile drivetrain warranty and after that they don't care!

 

Definitely change the fluid if it looks dirty. It does take a fair while to do it properly so maybe they just topped it up and lied? It should definitely last longer than that. Burnt fluid indicates high heat internally - could be the cooler is failing (apparently they tend to burst internally and leak coolant into the ATF...!) - it's possible that he left it with 'issues' too long and damaged the clutch packs. You may be able to salvage it by doing an extra-thorough flush to get the gunk out, mine was pretty bad when I got it but is fine now.

 

One word of advice, if you do fit an external cooler don't use Mocal's smaller model of oilstat - the gearbox pressure's too high for it and the two halves will be forced apart until it leaks...mine's drinking ATF until I can get the replacement fitted. That said my gearbox temperature is constantly between 10 and 15 degrees cooler than stock so it's still worth doing!

 

Stone

[alexvr6storm 10]

Update! Finally got VAG COM done and it's coming up with Code: 281 Vehicle Speed Sensor (VSS) fault - is this located on the auto box?

[Stonejag 10]

Depends on the year, but probably. This may help: link.

 

Are you also having trouble with your spoiler? If that and the speedo are working OK then it would prove that the sensor's fine and the fault is in the wiring between the sensor and the auto box ECU. I think the vehicle speed signal is always on blue/white wire so that may help you trace it. There are wiring diagrams in the Bentley too, but it'd be worth removing the connectors from gearbox and auto box ECU, giving them a good spray of WD40 and reseating them just in case...

 

Stone

[alexvr6storm 10]

Thanks Stonejag, spolier seems to be OK and no problems with speedo but I would say it is becoming more erratic on the gear shifting and getting 'clunkier' too... Where is the auto box ecu located exactly? Will definitely have a good look tomorrow at the sensor and wiring.

[fla 9]

It's behind the rhs kickplate under the bonnet release cable.

[alexvr6storm 10]

Cheers Hasan, had a look and connections look fine tbh. With the VSS fault code coming up do you think its most likely to be the sensor at fault?

Have seen this on ebay which looks to be the one :http://www.ebay.co.uk/itm/120736484639?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

For £25 and a bit of time i figure its worth a shot...

Having driven it with this problem for a while now it's 2-3 that's the issue, 1-2 and 3-4 are fine. I now have to give it everything to get it to change from 2-3.

Also Stone, I think you might be right about the garage not being honest. Wiping the ATF dipstick on a tissue it's more of an off red/brown than a tizer red, i think they just topped it up a bit as you suggested and charged my mate £150 for the pleasure! Think i will replace sensor first, then change the ATF and if no joy after that will be looking for a nice low mileage manual box!!!

[tbvr6 0]

That is not the right part. That is the electromagnet which fits near the shifter to lock certain shift positions. I think you are looking for something more like this. :

 

http://www.ebay.co.uk/itm/Vw-Vehicle-Speed-Sensor-For-Auto-Transmission-4-Speed-01M927321B-RPM-Sensor-/300655551190?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item460077a2d6&_uhb=1#ht_12638wt_992

 

But check part nos first.

 

Tony

[fla 9]

I would drain and refill the gearbox tbh. The tolerances in an autobox are very fine and the routes in the valve body can get gunged if you are using 'old' trnsmission fluid. I would drain and refill twice at least as a lot of the fluid stays in the torque converter. some places can use a pump to drain it out, but tbh, i wouldnt bother. Just fill it up and drain again after about 50 miles and see how you get on. Check the colour of the second drain of fluid, it should be partially brownish, indicating that more of the old fluid has been removed.

You can use a friction modifier - Lubegard is very good. Try to avoid the cheapo Wynns. The autobox is actually quite nice to drive with when it changes well - i still miss mine at times, especially when driving in traffic...

 

I have my old torque converter if needed.

[Stonejag 10]

I found this page very useful: link

 

Basically you drain and refill, drive for 5-10 miles, then drain again, change the filter and refill. Made a huge difference to mine.

 

If you don't end up with Hasan's torque converter I might nab it as a spare...then again his old shifter cable snapped on me on Friday! ;)

 

Stone

[fla 9]

make sure you get the right filter - there are two sorts, one is a push fit onto the bottom of the valve body. The other one (that you need if yours is a 94VR) is a screw fit. Torque on the bolts is about 10Nm.

 

Stone, how did you manage to snap the cable??? Obviously stronger than you look, lol

[Stonejag 10]

When I complained about the adjustment to the garage that fitted it (it kept slipping, D moved to where 3 should be, locking the shifter in N made it reverse!) they overtightened the nut that holds the cable outer and putting it in Park snapped it :( Either that or I Hulked out on it!

 

It's not exactly hard to get right (gearbox in P, shifter in P, tighten bolt to 20Nm) so not sure how they managed to screw it up, especially when I loaned them my Bentley! At least I had a spare attached to my old shifter, I dread to think what they cost new...

 

Stone