Went through the same fears. Though mine at about 260k. The gauge would move, but some days it would be pegged at the top, other days be pegged to the bottom at idle and then move up. I replaced the sending unit, it seemed to help for a few days. About a month ago the gauge just stopped working. You can check the pressure w/o removing the filter, if I recall. Mine was fine. It’s the gauge cluster. You will spill some oil. About half a cup. I’ll probably get an electronic after-market. I’m keeping 2 100’s, 2 GX’s and A 4Runner going so a cluster rebuild is wayyyy down on my list.
