Is it possible to use an AM crystal in an FM transmitter? I have a buggy with a Futaba transmitter running 75 AM an obviously do not get a lot of range. Wondering if I can swap crystals to AM 27 to get more range or will I have to buy new trans/rec?

No these are incompatible.

I have run Futaba 27 mhz, 75mhz (AM and FM), and PK3 with Spektrum module and Spektrum receivers. Never had an issue with range on any of them. I run indoor and outdoor. Maybe there is another issue. Could be cracked crystal, loose pin in receiver, or bad antenna wire, or antenna wire that has been cut.

Thanks guys. I might replacing the crystals to see if that will work as it seems everything else is in working order. Seriously though; last time I drove it I could about 20 yards max and the buggy would start spazzing on me.