ORIGINAL: BarracudaHockey
and you shouldnt even use different manufacturers crystals in a reciever unless they are meant for it.
And please listen to this advice. Your receiver might "seem" to work, but you could have lost a lot of range.
It is even worse in the transmitter; you might be a danger at the field, transmitting on your neighbours frequency in addition.
TX and RX Xtals have different characteristics. In a receiver the Xtal works without changing freq. In the TX the Xtal have to be able to deal with deviation. Deviation is a change in freq, and this is why it is called FM. The frequency is changed to code the signals, or shifthing.