I've been putting off completing this exact job to fix what I think is the final oil leak I have because one of the two 10mm nuts on my pedestal (furthest from the firewall) seems to be rounded and the non-ratcheting wrench I have just slips around the nut, but the other comes off fine. Not sure how it could be rounded by in such a tight space but we'll see once I finally get it off. I'll be trying either new extensions or the ratcheting 10mm ideas in the next few weeks hoping something grips enough to break it loose. ^^

 

^longshot, but try a 9mm and/or an SAE size. Possible someone used non-OEM hardware.

 

Memory serves the closest SAE size I tried was 3/8" and 9mm were too small, but the 10mm grips for a second and slips eventually which is why I assumed its "rounded". But I'll definitely try again before buying anything else.