1992 Ford Explorer smells like burning oil

check to see if there is oil on exhaust manifolds. If you recently changed oil an dpilled some on cover it often drains on that. also check valve covers for leakage may be that.

I smell gas and they used synthetic oil 10w30 could it be rms

If you smell gas see if there is a fuel leak if not it may be an engine problem so scan for codes and check fuel pressure with a gauge auto parts rent it. type of oil doesn't matter when you smell it burning.

When on hot engine it can burn n smell that what happping I looked I was told its rms

I have no idea what rms is so go back to the person tha told you that. I can be of no further help

It rear main seal

ya it could be that dripping on exhaust pipe all you have to do is look. could be a tranny seal as well.

I just talked to my mechanic he rebuilt my transmission and changed seals I have nothing leaking from exhaust

I have no further comments

you were right is leaking from the lower manifold and the topper and manifold I got missing bolts