I have a 99 silverado, and it has a steady leak from the rear main sea:no:l, i know that its a couple hundred bucks to get that fixed at a shop. And I'm a little hesitant to drop the transmission to replace the seal. I saw some engine oil additive or something that said it repairs the rear main seal to stop the leaks. I think is was called No Leak. I was wondering if this stuff worked and what brand to buy, because i noticed some other brands like Bar. Thanks!