2.5 TDI AUTO TRANS thread

[Greg Roles]

I'm now down to just the nasty 3-4 flare, bang back into 2nd when slowing down, and box is throwing a 17114 gear ratio limp error at times.

Pulling the valve body again now, fitting the new loom, adjusting the K2 clutch 1&1/2 counterclockwise for the flare, the B1 brake 1/4 clockwise for the 3-2 bump, and recleaning the speed sensors, as that is one possibility for the error, but so is fluid level and several other god damn things, pretty "vague" error sadly....

See what happens.

[Greg Roles]

Interesting findings, there's a tiny mesh filter insert in the remote cooler return line, it's a bitch to get out without breaking it, just an o-ring press seal but still tricky, and mine was totally covered in crap. Would not have been flowing much! Even my you beaut repair manual barely mentions it nor lists a part number, so going to probably ditch it for an external inline filter that I can easily replace.

Second the external plugs to the box were dirty and covered in oil, seems all the fuel pump / water pump / fuel filter / EGR valve oil leaks end up going over these connectors. Mine were very dirty, and the seal in the speed / temp sensor plug in particular was swollen with oil, and I'm not sure the plug was fitted properly. I've ordered a new loom on that side now too, as I figure my gear ratio error issues are likely to come from this side of things, and the connections need to be as good as possible. Something to watch on these vans, the placement of these plugs is prone to oil and dirt build-up. Sure they are quite sealed, but over a decade....

Going back together this arvo, and see how the clutch adjusters etc have gone.

[Sunny43.5]

How was the filter pick up at the bottom of the sump , that one in ours got blocked after a service by VW which then lead to total destruction as they did not remove the sump . When they refilled it the clean fluid flushed the box so there was even more crap in the bottom and when the pump kicked in no fluid got past that filter causing the damage .

[Greg Roles]

Fine, someone had been into my box before I got it, the prior owner said the gearbox was "new" although that also turned out to be a lie, someone had replaced the fluid and main filter prior to my ownership, one solenoid does not match the rest, and on first opening there wasn't a ton of metal on the magnets although the fluid was indeed dirty. The filter I pulled had a bit of crap, but a long way from blocked.

The small filter is a concern, as it's not obvious, I've yet to get a part number or even find a picture online, and it will drop the flow through the cooler dramatically. It's going to clog way before the main, bottom one does. Another poor design, and another thing easy to overlook.

Fluid going back in now, and adaption drive this morn, fingers crossed.....


EDIT: welp, 50kms of driving through the gears endlessly and using vag com to clear errors, and the problems remain. All I've managed to do by adjusting the clutches a bit is make the box pretty much skip second under acceleration, the bangs and flares I had are still present without change. As VW warns the problems get worse before they get better when re-learning, and you notice that the first few times, but I've gone through the gears and tried adapting from scratch three times this morn, and it ends up the same flares and bangs, so I've got problems the software can't overcome.

I even recoded the TCM back to the xxx328 Golf 5k or whatever I found it initially coded as, and even that ended up the same, it just climbed through the gears faster where when coded as transporter it stayed in each gear longer, especially 5th.

My limp error is gear ratio, and as such I've ordered new input and output speed sensors, just in case, as well as the wiring loom for those just to be sure. I'm admitting defeat on this valve body and sending it off to the USA for a rebuild and upgrade with the improved Sonnax parts for circa $1500. From there if any problems remain, well it's worn box mechanicals, and that will be the next battle. Clutch plates scare me far less than all the tests and precise machining a valve body rebuild comprises of!

At least in all this testing the engine is flawless, running like a champ, not too noisy and not an oil leak in sight. If I can get the box to the same level, I'll be endlessly happy!

This van is definitely a Decepticon.

[Greg Roles]

A huuuuuge thread on an "alternate" site, I've read the whole thing whilst being dismayed this arvo, the good info is the first few pages, with a bit of stuff towards page 30 onwards pertaining to the 3-4 flare I have specifically. This is possibly a k2 clutch seal ring that fails and Sonnax have an updated part for. A long read, but tons of experiences amongst the endless queries for diagnosis.

My experience with the 09G Transmission... | VW Vortex - Volkswagen Forum


I'm going to most likely still get a remanufactured valve body just to eliminate that entirely before I consider going into the innards, and of course this god damn seal ring part is right in the back of the box. A ton of talk towards the end of the above thread ( say page 28 on ), about the benefits of upgrading the earlier "large" solenoids like I have with the later "small can" improved ones. Very interesting....

[BrianJ]

Can you apply some sort of pressure test to the K2 clutch to make sure its faulty before dismantling the entire box.

[Greg Roles]

Good point, and will absolutely do before trying to get this beast of a box out!

The next step is to drive it a few more times from cold, I just took it out again now and the ATF temp was 40 degrees, drove fine till it hit about 70, then all the drama's started. That's the rough test for mechanical issues vs fluid pressure issues. Thing is it could still be adapting, so a few more drives to get a better feel of the problems.

Next step if that continues is a valve body makeover, probably quite due at 265 thou kms to be fair, so I'm not overly upset. Missus ain't happy though, no camping this weekend!

Summary of my gut feel is the 3-2 bump has always been there, and has not changed since the Trans-go shift kit, valve body clean, solenoid makeover and loom replacement / clean-up work. That 3-2 solenoid / circuit / TCM control is over fast / pressured.

The flaring is new since all my work, and I'm at the stage of trying to determine why the bad 3-4 flare. 3-4 has it's own clutch, and this notorious seal ring that spins or some such, also causing 3-4 flare. All the shifts were good just before when the fluid was 40-50 degrees. I also don't recall 3-4 flaring before all the work, so that again says valve body, not mechanical part, as I messed with the valve body and the flare was born. I recall the car basically racing through 3rd into 4th and the poor thing labouring to get up to speed, but no flares.

[Greg Roles]

Well as an update to this thread, and me messing with valve body clutch adjusters and endless adapts, I've bitten the bullet and paid an American company send me a reco valve body with all the Sonnax upgrades. Cost about $1800 all up delivered, but they didn't want my body up front and are sending me another one to put in which is super handy as then the van isn't sitting around undrivable as I was expecting.

Their eBay listing has some good info, so I'll put it up here for future reference. If the problems continue then it's further testing, but at least with a properly reconditioned body I'm just down to the actual box mechanicals which make FAR more sense to me, the valve body hydraulics are another world I only "kinda" get. I do understand that wear in the bores etc causes leaks, which in turn cause issues, and at my kms no doubt there is wear!

Will report back on the reco body once it's in, fingers crossed ( do that far too much with this van! )

[Greg Roles]

As a follow up the US guys didn't feel confident they had the exact 09K valve body to send out up front, as the 09K was never released into the USA. So I've finally pulled my body out ( on the god damn street as car isn't drivable till it returns ) and sent it over. They are working on it as we speak. My biggest worry is the 3-4 flare my messing around has "created", the end clutch bush can cause this exact issue and of course it's right in the back of the box.

Fingers crossed when the body goes back in it's sorted the issue!!

[Rebuild]

The flaring is new since all my work, and I'm at the stage of trying to determine why the bad 3-4 flare. 3-4 has it's own clutch, and this notorious seal ring that spins or some such, also causing 3-4 flare.

been a long time since my gearbox was done, but Dave at Automatics of Marion, did some of his own fixes to the box, and i seem to recall him mentioning placing some dowel pins in there to stop certain things from spinning unnecesarily, and wearing out