Gear oil is the stink that keeps on giving...

I've had such a stench under the hood of my truck ever since I did the engine swap. I never smell it in the truck, but every now and again, I'll smell it with the hood down - and always with it up.

Like you, I can't figure for the life of me where it comes from. I've changed the oil in the diff, t-case and tranny. There appeared to be none missing from any of the above, so I'll be damned if I can tell where the smell's coming from, but it's always there.

My truck's my DD now too and it runs fine. It just smells when I raise the hood.

My only theory is that perhaps I have a small leak somewhere that puts a drop on or near my turbo. I run synthetic oil, and the smell of it burning is pretty fowl.

I don't burn any oil and there's no smoke from the tailpipe. After my experiences with spinning the turbo shaft nut and dumping oil in the turbo, I know what to expect if that circlip (seal) at the back of the shaft goes south. You'll look like the mosquito fogging machines of old rolling down the highway. There will be no doubt in your mind what's going on in that regard.