Passat B6 3.2 FSI 4 motion DSG oil change mystery

[Old Navman]

Gday,

Hi all, the following is a bit of a mystery...
In Aug 2016 DSG (250) transmission oil & filter were replaced. Vehicle was on a flat, even surface, 5 litres of oil poured in, temperature of transmission oil 39C (checked on VCDS), transmission "drained" until it was just dripping oil. Forward to October 2017. (Yes, I'm aware the DSG oil did not have to be changed yet) Drained the DSG oil, measured exactly how much oil has come out - 4.3 litres. Measured and filled the DSG with 4.8 litres, cycled through the gears, at 40C - no oil came out. Next day poured another 200 ml - nothing came out. No leaks from transmission evident. True the car has done some km's - in fact over 250k but is in a good nick. Any ideas what could be happening here? Why the discrepancy in oil volume?

[3C4M Guy]

It's a mystery to me but I hope someone can shed some light on it. I have to change my DSG oil and need to choose which method to measure how much to put in. Your experience makes me think it's better to use the factory method of overfilling then letting out the excess by monitoring the temp via VCDS rather than simply measuring how much came out and putting the same back in.

[Umai Naa!!]

They're always underfilled from the factory.

Overfill it with the full 5 litres, and drain the excess as per their instructions.

With regards to the original post, is it possible that the level tube was not screwed all the way in, and tightened (by hand)? They do have a tendancy to back themselves out.

[Old Navman]

@ 3C4MGuy - yes, I was thinking exactly that when I poured in the 4.8Lt at first however when nothing came out at 5Lt that got me really thinking.

@Umai Naa!! - yes, during the last oil change the mehanic used ratcet wrench so if anything the tube should have been sitting in higher, more oil should have been poured in order to drain consequently leaving more oil in th gearbox? He used ratchet wrench this tme too but did not use a torque wrench to tighten the tube according to the specs (20lbs?)

[Umai Naa!!]

Don't really need a torque wrench on it, it's only plastic and just needs to be tightened firmly by hand (i.e no wrench, just an allen key).

[Bora Sport]

2 points. 1. Did you measure the oil in the filter and include it with the amount drained out?
2. My mate just recently did a DSG service on my wife’s 2010 Jetta 125TDI and he couldn’t get more than 4 litres in it. The car seems to be driving fine but I’m concerned that we should put it back on the hoist and check. Perhaps he didn’t screw the tube in far enough but I told him of my concerns and he reckons he checked it again.

[Umai Naa!!]

Car needs to be running to check the oil level.

The oil in the filter housing drains out the bottom. Not much is held in the filter itself.

[Bora Sport]

Yes it was checked while running while on the hoist.

[Old Navman]

2 points. 1. Did you measure the oil in the filter and include it with the amount drained out?
2. My mate just recently did a DSG service on my wife’s 2010 Jetta 125TDI and he couldn’t get more than 4 litres in it. The car seems to be driving fine but I’m concerned that we should put it back on the hoist and check. Perhaps he didn’t screw the tube in far enough but I told him of my concerns and he reckons he checked it again.

Yeah, agree with Umai-naa!!. It's documented, you should be able to pour 5lt in order to fill (service) properly drained DSG t/x.

[Bora Sport]

Wouldn't the gearbox for a 4 motion hold more oil than a 2 wheel drive?

[Umai Naa!!]

Nope, not with these.

Only the casing is different, to accept the bevel box which sends power to the rear.

[Bora Sport]

So no oil in the bevel box?

[Umai Naa!!]

Not DSG oil, no. It has its own oil.

[3C4M Guy]

OMG. Does that mean the drivetrain has 5 separate oil supplies - engine; DSG; bevel box; Haldex; and diff/rear axle?