Synthetic fluids - what I know to be true

[jmil1974]

Here's what I do know for sure from my experience and others more experienced than I:

The Chevy mechanic that lives next door only puts synthetic fluids in when possible. He told me it runs significantly cooler in differentials, especially when towing. No reason it wouldn't be the same story with trannies or engines.

I also know that if you run synthetic in an engine with older gaskets and seals, it WILL leak. It's better, but it's messier and likes to find a way out due to it's smaller molecular size and "slipperiness."

I recently mixed conventional and synthetic in my diff. I bought Quaker state regular dexron to do my tranny fluid and QS 10w40 4x4 for my motor. I would use synthetic but I don't feel like changing all the seals at this point. If there are no leaks in my tranny or "new" motor, I may go synthetic on the next change.

Opinions, especially on brand experience encouraged.
Thanks!
Jason