Originally Posted by mredzadventure
The set should work you will have to replace both crystals in the transmitter and receiver. They come in a set so you should be good to go. Here is channel #2 http://www.ebay.com/itm/Traxxas-2032...item3f1ae4eae6
This is what you have now ? You cant mix channels 2 wont work with 6 you need a matched set.
If using the same technology, so 27 Mhz AM for example, the number of channels doesn't need to match. You can perfectly use a 8 channel receiver with a 4 channel transmitter, you just can't use all 8 channels naturally as the transmitter is limited to sending out . It's different if the 4 channel radio uses a different modulation, like for instance 40 MHz FM can't work with 40 MHz AM.
Do beware that a receiver cristal can't be used in the transmitter, though, and vice versa. And even a transmitter cristal from another brand of the same modulation type radio is not guaranteed to work in a different transmitter. You will need the transmitter cristal for that particular brand and type transmitter. On the receiver side things are usually less critical.
Btw, how much are those cristals? In some cases it would actually be cheaper to get a entry level 2,4 GHz radio, like the HK GT-2 or GT-3.