When switching from Army to the Marine Corps, will my time in rank transfer over?

No, it won't as SSgt Christophe Murphy has stated you'll more than likely be assessed into the Corps as a Pfc. I had two friends enter the Corps after service in the Army. One was a SGT and the other a CPL. Both graduated boot camp as Pfc's.

TIG is always adjusted when taking a reduction in rank. TIS won't be reduced, but TIG will.

I had a SFC in Armor 19K CAARNG ( Back when marines had real tanks) he was a Master Gunner E-7. The marine corps would not take his rank. He would be an E-1 As a marine corps reservist. He worked as a civilian contractor at china lake to a job on the East Coast. He decided not to join them. I lost track of him and I don't know if he joined a national guard unit instead.

I would say the answer is no.But let me ask a couple leaders here on RP.

CSM Charles Hayden CSM (Join to see) CSM Chuck Stafford COL Randall C.