The Black Pearl

Robin_Cox

Member
For once, I am lucky in that there was some free space! I couldn't get both horns crammed in the original location, the Klaxon/Mixo are quite a bit bulkier than the Hella beeper.
The bottom of the FCU gearbox:View attachment 78157
I know it isn't a Tdi gearbox, but if they've put the drain in the same location, you need to undo the rear gearbox mount bracket where it locates onto the gearbox and rotate the folded metal plate down - on the Tdi the drain plug is in the casing floor that is obscured by the plate. If it is though, don't drain it until you've established where you can fill it!
 

VAG fool

Member
I can only think that the 1.4 petrol box is a rather different animal to the 1.4 tdi item.
Vibration periods, torque requirements etc and this is reflected in its design?
The lower plug in the end cover has the familiar 17mm socket as per any other VW or Audi and is at the lowest point on the transmission.
The upper one is at about 3 o'clock on the diff cover and is slightly smaller.
Everything online says 1.9 litres capacity for both petrol or tdi.
 

Robin_Cox

Member
I can only think that the 1.4 petrol box is a rather different animal to the 1.4 tdi item.
Vibration periods, torque requirements etc and this is reflected in its design?
The lower plug in the end cover has the familiar 17mm socket as per any other VW or Audi and is at the lowest point on the transmission.
The upper one is at about 3 o'clock on the diff cover and is slightly smaller.
Everything online says 1.9 litres capacity for both petrol or tdi.

The AUA/BBY gearbox is a different family altogether to the Tdi boxes - MQ200 instead of MQ250, if I remember correctly (ie, 200nm rather than 250nm torque limit), magnesium casing as well for the weight reduction compared to aluminium. I have the VAG internal self-study manual document somewhere where this is explained.
 

Kleynie

Member
We’ve done the gearbox oil twice, once on a AUA and once on a BBY, if I remember correctly the dog bone mount has to be removed to gain good access to the drain plug.
We struggled to get 1.9 litres of oil in, we used some 15mm polypipe and a funnel to fill.

let me know if you need further info and I will ask Adam, his memory is 30 years younger than mine!

Ian

edit, just checked with Adam and the drain IS accessible without removing the dog bone. I should know better than trust my memory!
 
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VAG fool

Member
So is the filler on the other side of the diff housing i.e. on the inboard side?
What a genius bit of design 🙄
 

thejohn

Member
Hi VAG fool I have heard you can fill the box through the reverse switch. I only heard about that after I'd changed mine with a funnel and a piece of garden hose.
John
 

Kleynie

Member
Hi VAG fool I have heard you can fill the box through the reverse switch. I only heard about that after I'd changed mine with a funnel and a piece of garden hose.
John
But why would you want to do that? The idea is that you fill through the fill plug, with the car on level ground, until the oil comes out of the fill point. That way you know you have enough oil in the box.
It will never take 1.9 litres as there is always some old oil left in the box, so even if you measure 1.9 litres that could mean you are overfilling the box if you do not use the fill point.
Ian
 

thejohn

Member
But why would you want to do that? The idea is that you fill through the fill plug, with the car on level ground, until the oil comes out of the fill point. That way you know you have enough oil in the box.
It will never take 1.9 litres as there is always some old oil left in the box, so even if you measure 1.9 litres that could mean you are overfilling the box if you do not use the fill point.
Ian
Good point Kleinie. As I said I only heard not done it. I did fill on level ground until seepage out of the fill point. The best way to see if that idea is any good is if someone with a spare gearbox measure the heights of both the fill point and reverse switch and see if they are on the same plain.
John
 

VAG fool

Member
That will be the filling plug then:
IMG_20210401_175437_8.jpg

I was also a little bothered by the angle of the extension on the dogbone mount, as though it had been bent up by a spanner monkey (who managed to nick it with an exhaust saw) but a look at the parts catalogue illustration shows it having a distinct bend upwards.
Screenshot_20210401-183400.png

I cant find a heat shield listed that is supposed to fix to it, must be a 1.6 thing.
 

VAG fool

Member
Job done, no dramas. Only 0.75 litres of brown filth dribbled out of the drain, the box is a little damp around the offside inner CV so the seal is on the way out.
I got 1.9 litres in by slightly raising the rear of the car, the gearbox level is very sensitive to slight inclines. I got to 1.7 litres or so before it dripped into my catch bowl then jacked it up a little, maybe only 40mm nose down overall.
IMG_20210409_183532_0_resize_37.jpg
IMG_20210409_185854_5_resize_36.jpg
IMG_20210409_195313_5_resize_77.jpg
 

VAG fool

Member
Offside diff drive flange has definitely got a slight weep, that explains why the gearbox was almost empty. Seals ordered for both sides and I'll let the oil stand overnight to strain out the worst of the muck that it flushes out.
 
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