Cam tower leak from what i've heard there are 3 spots it's been known to leak oil. Sometimes people notice it by oil dripping down on the skids. Sometimes it drips onto the exhaust and they smell burnt oil. I have the leak myself, but mine is on passenger side basically just above the top of the shock. It's pretty common a lotta Tundra guys have it on the 5.7. Something to do with the glue used to seal degraded over time. As you can tell from pics, very labor intensive if you do want to fix. zI personally just keep an eye on it and check my oil level regularly, never been low so it's just a small leak. I've never had any oil on my skids nor smelled burnt oil though. Just get a flashlight and look around for it, could be on any side where the seal is. The photo im showing is looking through the passenger wheel well