If you are having trouble with the 60-120 retracts, check the current draw. If the gear mechanism binds, it can get quite high, (1-1/2A or so). The normal current draw with the gear in motion (without wheels) is about 300-500ma with both main gears in transit. The highest peak draw seems to occur when the gear is just starting from the retracted position. There is a current protect circuit that trips when the current draw is to high for too long. I'd go along with the idea of using a power source other than that used for the receiver and flight servos. If you have high current draw, try loosing the three screws that hold things together. If this helps, it may be that the side plates are too close together, slightly misaligned, or the brass rod shuttle is binding on the side plates and/or the gear fork.
Light lubrication may help.