Gear Oil Not Draining? Troubleshooting Guide.

A friendly hello to everyone.

Today, a completely bizarre problem cropped up in my workshop:


I want to change the transmission oil in a Caddy (105 hp 1.9 TDI with a 5-speed manual transmission, chassis code: JCS) that has 185,000 kilometers on it.

Oil drain plug opened -> some oil came out -> plug re-tightened slightly to prevent further dripping.

Oil drain plug removed -> approximately 0.5 liters came out.
Oil level check reactivated -> Oil continues to leak from that location until the "target oil level" is reached.

If you check the oil level by feeling the transmission housing, it still feels full of oil, even though the drain plug is open??

I've also tried gently blowing compressed air into the inspection opening, but it didn't work.

Where inside the transmission could something get clogged?

Hello,
Are you 100% sure you loosened the correct bleed screw?
Please take a closer look; I can't imagine you're constipated. If necessary, you could try using a wire or something similar to resolve your supposed constipation .

Hi,

Yes, the correct screw is loose, and I'm not doing this for the first time .

In addition, approximately 0.5 liters of oil leaked out.

I've also tried poking around with welding wire and other things, but unfortunately, it didn't help.

I have no idea how it works with a manual transmission. With a DSG (Dual Clutch Transmission), the "control opening" is no longer used, and the drain opening is somewhat different.

A further pipe is screwed into the drain opening, which indicates the correct fill level. The drain screw is approximately M20 with an estimated 12mm internal hexagon. Below the drain screw is a pipe that needs to be unscrewed using a 6mm or 8mm internal hexagon wrench.

It sounds like you're experiencing the same issue. So, take a look inside the drain hole. If you see a black surface with a hexagonal hole, that's the culprit.

Greetings.
Guste.