2.5 TDI AUTO TRANS thread

[Greg Roles]

Hi All,

My 2009 BPC 174 engine is running like a train, seems it's sorted after the saga I've had getting there. See my pinned info thread if you are looking for engine specific info, or want to see the agony of repairing this unit from a zero knowledge base.

My 6 speed tiptronic auto is the focus of this thread, as I'm finding on long trips it will flare, clunk and go into "all numbers" highlighted soft limp under certain conditions, and obviously needs a rebuild sooner rather than later. It is still driving fine, and on the recent 500km weekend trip only had three limp situations in heavy highway traffic, and a simple key off restart clears that.

I've limited automatic gearbox experience beyond solenoids, so in the interests of losing the rest of my hair, and entertaining you all, I'm going to endeavour to first research, understand and then rebuild this notorious gearbox myself.

What could go wrong?

I've now done a few thou and will drop half the fluid - as much as will drain anyway, fit a new filter and gasket, and apply the "Mr Shift" USA O9G kit to the solenoids and drive like that for a few thou more. I've no doubt it probably needs a drum, pistons and frictions/metals, as well as a solenoid rebush in the least, but see how the fluid and shift kit goes.

I'm installing a temp gauge on my external cooler so I can watch temps, and I think the fan that came with the external cooler should ideally be fitted, I have it off for clearance for now, and when it got hot on the big trip, it seemed to play up more.

Let the messy ATF games begin ( hate that stuff most of all! )

Greg.

[Rebuild]

Mine only cost $9K for a full rebuild , although it was in and out 3 or 4 times, doing partial fixes. Maybe would have been $6K-7K for a once off full rebuild.
It was pretty much all good till about 160K km, then started clunking into drive. I had done my own (half)fluid and filter changes at 75K and 137K. Gearbox finally fixed at around 180K
Trans rebuilder showed me the internals a few times and said basically the seals had gone hard causing probs. I found some rubber bits in the pan when i tried an oil change. I didn't run an external trans cooler, just the standard VW oil/coolant exchanger thing which lets the oil cook at a minimum of 90C(coolant temp).
I run an external air/oil cooler now.
I'll still be doing my own oil and filter changes every 50K or so.

If you don't get any joy from your attempts, all i suggest is a full one-time rebuild. It won't get any better.

BTW, here's my tale of woe
The Torque Converter Auto (NOT DSG) T5 thumps into drive when cold

[BrianJ]

My 2006 tiptronic started going erratic at about 280,000 km. After trying additives which seemed to help a little, the answer was simple, took it to Reliable Auto repairers at Albion Brisbane, and they said the problem is usually a worn valve body for one or more selectors and they can get it reconditioned by a man at Coomera QLD, then reinstalled cleaned and all other parts tested all for $2400. So I got it done and picked it up in about three days working perfectly. As it wore in, I needed to reset the gearbox computer a few times back to factory settings. Its now done 350,000 and still going good.

https://www.vwwatercooled.com/forums/f136/t5-faq-how-thread-up-august-2009-a-32995.html#post846365

[Greg Roles]

My 2006 tiptronic started going erratic at about 280,000 km. After trying additives which seemed to help a little, the answer was simple, took it to Reliable Auto repairers at Albion Brisbane, and they said the problem is usually a worn valve body for one or more selectors and they can get it reconditioned by a man at Coomera QLD, then reinstalled cleaned and all other parts tested all for $2400. So I got it done and picked it up in about three days working perfectly. As it wore in, I needed to reset the gearbox computer a few times back to factory settings. Its now done 350,000 and still going good.
https://www.vwwatercooled.com/forums...tml#post846365

Great to know Brian, and handy for me in Caloundra too, thanks a lot for the intel.

I'm going to try to rebuild it myself for the experience, and if that goes tits up, I'll be onto the Albion guy. I've already got some solenoid bushes on the way, and the solenoids are the same for the common 09G box. Seems our transporter 09K auto simply has different friction plates and metals to handle the bigger torx, but there may be other differences. The master gasket kit seems identical, even the pistons seem common. I'm buying an 09G rebuild manual tomorrow out of the states.

Luckily it's not my daily nor needed for work, so if it's off the road for several weeks only my missus will get upset we aren't doing weekenders. The big upside is how good the engine is now, and given the low kms I will really put on this once a month camper, should see it out for quite some time.

[Greg Roles]

I'm going to do the stub axles and driveshafts while in there, have read just doing stubs is risky given they wear as a set.

Interested to know if anyone can tell me about these "stronger" revised stubs VW have, given they seem to be the weak point.

I will probably just go generic shafts given my low use of the van, hate to think what genuine costs.

[Rebuild]

I think the revised gearbox stubs for the driveshafts are just longer for more engagement, so they don't strip or wear splines out so much. Haven't done them myself.

[Greg Roles]

I think the revised gearbox stubs for the driveshafts are just longer for more engagement, so they don't strip or wear splines out so much. Haven't done them myself.

Thanks Steve, makes sense, not much else they could do apart from alloy / heat treatment.

[Greg Roles]

OK, I'm into my trans this arvo, and am currently fighting the good fight to try and get the valve body out without having to raise the engine off the lower subframe - of course the valve body *almost* drops straight out, and if someone with some foresight had allowed about 2cm of clearance in this area it would, but of course the T5 factor comes into play.

First thing I noticed was one of the two looms has gone hard, and a lot of the wiring insulation has visible cracks and gaps. Has done the typical wiring in hot oil thing, just like the old PD injector loom that used to fail and became part of that PD injector recall in the MK5 era. Anyway the common O9G loom is identical to our 09K looms, and rather than pay the $300-$500 for an OEM one, there's tons out of China for about $50, but with the usual few weeks delay. I found the temp sensor / input and output sensor loom is fine, and the insulation and plugs seem pliable as normal, perhaps it's been replaced already. It's the solenoid loom that two of the blue plugs snapped in my hands, and the insulation is rock hard on, so that has to be replaced for sure.

Once I get the valve body out I'm going to do the shift kit, reinstall the interim patched up loom and see how it drives. I found a great video outlining a few things to watch out for, and of immense interest, mentions the adjustments on the other end of the main solenoids to change shifts and gear changeover ( flaring?? )!! Going to take note in where my problems actually are in the various gears, and try some adjustments once the China loom arrives and I have this thing back off for the install.

Another interesting thing this video alerted me to is the fact that the auto shown has separate diff oil to the trans oil, but looking at mine there is a blank plug where the video shows a drain bolt, so perhaps this was an earlier T5, and my mid 2009 T5 diff is indeed sealed for life. Will investigate.

I'm sticking with my initial Titan 4400 trans oil, but I'm sure any approved oil will be fine so long as you don't mix if you can help it between changes. I'm also putting in the Lucas stop slip stuff, as for $30 how can it hurt and I've read good things about it several times. This will then be my second half fill of the box, and what came out looked just fine, but it's only done a few thou, and this is really a second flush as much as anything, and a swap of filter too, only because they are cheap and I had a Ryco kit on hand.

Aussie valve body info video - 09G / 09K / TF60SN Valve Body Removal and Replace - YouTube

Late T5 auto temp / input and output sensor loom:



Late model 14 pin Solenoid loom which is hard and buggered in mine:

[Greg Roles]

For future reference there are different looms that changed around 2005 for our vans. This info is from Alibaba, and is O9G specific, so best do some extra research if you find a loom problem like me for our O9K. Here are all the O9G looms I found in China for reference.

[Greg Roles]

Can confirm valve body comes out without having to raise the engine off the subframe, but boy is it a Tetris puzzle till you work it out.

Undo the very outside bolts down each side, noting the short vs long ones. Strip the body of all the looms etc, be very careful withthe plugs and take some pics of where it all goes, it's real easy to mess up the plugs for the N92 / N282 solenoids, all the rest are keyed. Wriggle it down at the N90 front of van end and remove the accumulator piston and spring, see pic #1. Next, work on getting the passenger / non main solenoid side up as high as you can with the N93 area as low as possible at the left back of the valve body ( Pic #2 ). You can wriggle the N90 upper edge out with a bit of work, there is even a milled small cut out for the top 10mm bolt that hits the gearbox housing itself, but with some careful wriggling it comes out just fine ( Pic 3 onwards ). Goes back in the same way. Tricky, tight, but entirely possible.

1. After getting all the junk off, drop the front edge and get the accumulator piston and spring out ( arrowed ).



2. Next get the drivers rear side as low as possible, with front and passenger side high. Takes some work, so be patient.



3. Here is the top 10mm bolt and the cut out that helps it come out, it's bloody tight, and you need to man up and wriggle it.



From there it pretty much falls out.

[Greg Roles]

For reference to all these solenoids and directions, here's how the valve body sits in the car. If you print this pic out and hold it over your head, that's what you see with the pan off.

[BrianJ]

Very impressive write-up. The findings of the deteriorated cables is most interesting.

If its worth anything, I was told that when any piston bore becomes worn that the oil pressure is lowed due to the leakage, and this can effect the entire operation. I am not sure about this theory as I think the oil pressure is only applied by a solenoid during shifting.

I am following this with interest.

[Greg Roles]

Very impressive write-up. The findings of the deteriorated cables is most interesting.

If its worth anything, I was told that when any piston bore becomes worn that the oil pressure is lowed due to the leakage, and this can effect the entire operation. I am not sure about this theory as I think the oil pressure is only applied by a solenoid during shifting.

I am following this with interest.

Yeah, cause I reckon half the issue the old PD injector failures had was a hardened and cracked loom sitting in hot engine oil. Seems to me if these solenoids have to be within a particular resistance range, triggering them with a terribly cracked and bundled together loom in hot ATF is only adding to potential issues. I'm actually amazed my box was even working, the gaps and potential for wires to contact is that bad...I'll get some pics.

I'm in the middle of the shift kit, and have this arvo to crack on and get the rest done. I'll have a look at my valve bores too, thanks for the tip, will clean out the ATF properly and look for play.

[Greg Roles]

Wow, I see now why auto rebuilds cost serious cash, took me all arvo to install the shift kit in just the valve body, but it is a fairly complex bit of kit to pull apart for a first timer like me. The Transgo shift kit kit is exceptional, and the instructions are simply glorious.



I found one solenoid different ( older?? ) than the rest, and half of them were quite sticky. "Drilling" them out ( all long drill, see instructions below) was easy, and I don't really feel I actually removed much, getting them clean and the piston dropping out was a bigger thing. I just hand filed all the end caps off, you don't keep the stock "coin" end piece at all, so you can go a 2nd cut or rougher on the filing to get them off. Some were a bit tricky.

What the instructions don't point out, well perhaps they do somewhere, but when turning the drill by hand, remember to actually push the solenoid innards open with the drill, so you actually ream the whole "canal". Didn't discover this till my second one, so the first one only got a 3/4 drill ream before I sealed it all back up as I didn't push hard on the drill.

A STRONG small magnet is essential for getting retaining pins and plunger keys out, as is a few dental type pics, some cotton buds to clean things, some sort of cleaner spray ( I used WD40 ) and a micro drill chuck. The supplied drills are TINY, and I wrapped a little electrical tape around them and drilled carefully with a normal drill, wasn't ideal but got me there, but you really need to order a microdrill chuck from Jaycar or somewhere. Be gentle as the smaller two drills are TINY and would break real easy, plus the size obviously matters and is imperial. It;s a complex thing to pull apart, especially the main part, as there are pistons, tiny plastic check valves and a blaa bearing that can fall out of each "Clam" shell half when you split the main section. Thankfully the instructions are comprehensive, so they were a massive help. I would suggest leaving yourself a lot of time, have a lot of rags on hand ( ATF keeps coming out every section split, and I'd avoid drinking, your brain needs to be on high alert!!

[Greg Roles]

And for future reference, this kit is SO worth it, had to buy it through Amazon from memory as only they would ship to Australia, but I'm sure you could use myUS shipping forwarder or similar in a pinch too....