Took digging but found out what it is.

According to this post the only way to reset the plug is by disassembly of transmission.

https://www.matthewsvolvosite.com/forum ... 6&start=20

Hello, I replaced the angle gear sleeve recently and transmission oil started leaking between the transmission and angle gear. The inner sleeve was a little crooked in the sleeve but looking further in my friend found another seal that looks damaged. Does anybody have experience with this? I can’t f...