B5.5 passat TDI differential

[zzdiesel]

Does the differential have a seperate oil supply than the transmission?

 

[MEgearhead]

If you have the stock automatic GMR, yes the differential fluid is separate from the auto transmission fluid. If the car has been swapped to a manual 5sp it's all the same fluid.

 

[zzdiesel]

Thanks Gearhead. How does one check or change the oil? I don't recall that ever being mentioned.

 

[MEgearhead]

Check is pretty easy. There's a fill/check plug on the passenger side of the transaxle in front of the inner CV joint and just below the axle centerline. It takes an 8mm allen socket. Just fill it until it overflows.

Changing will be a little more difficult. Normally you don't change it. You can try to suction it out through the same plug with a pump and hose. Otherwise, you can take the chance of loosening the diff cover bolts and drain it out that way, but i wouldn't mess with them.

I have a picture of the side of the GMR I took out to manual swap mine. I have never been able to figure out how to post pictures. I got through the how-to up to the point of hosting and was lost at that point.

 

[MEgearhead]

Here's a picture showing the plug:

PXL_20230312_180441721~2.jpg

Diff side of GMR showing fill plug

forums.tdiclub.com

 

[zzdiesel]

Thanks again! Would it be 80/90 gear oil?

 

[MEgearhead]

The VW/Audi spec is G 052 145. ZF lists Castrol SAF-AG4. I believe that is a synthetic GL5 75W90.