PA-23 Dropping Gear

[OZAZTEC]

Help Please,

I own a 1978 PA-23 250 "F" model Aztec. We have been experiencing problems with the gear dropping in flight. There is a slight bump and the yellow caution light goes out. Setting gear up solves the problem for 10/15 mins. All seals have been replaced and the powerpack checked. Has anyone experienced this problem and any idea's to remedy. The A/c is going in for 100 hourly on 5/12 and any suggestions will be appreciated. My LAME is scratching his head.

Thanks,