Red gearlight remains on after retraction

[vincec]

We have a 68 PA31-310  , and for the past 5 or 6 flights we are having an issue on gear retraction. Our serial number is 198 so we only have a main gear door up microswitch on the left door. Everything works great on gear extension. On gear retraction after you raise the handle to up after takeoff the red light does not go out and so the gear handle does not return to neutral. However, if you recycle the handle down  to up neutral and then back up,  after about a second or 2 the red light goes out and about 8-9 seconds later the handle returns to neutral. When we put the plane on jacks everything works perfectly on the first try every time. In flight at about 110 mph it also works every time, but at 120 mph or more it doesn't. This was never an issue before. By the way, the left main gear door shuts fully and activates the micro switch. Has anyone seen this before, and what is the fix. It's driving us crazy that it always works on the recycle in the air and also on the ground on jacks. 

[Vince Collazo]

Problem finally fixed. Found that if gear retracted in level or descending attitude everything worked perfectly, but in takeoff attitude red light would stay on and handle remained up. Decided this could only be caused by either low fluid or air in the system. Filled reservoir till fluid came out of overflow drain and problem went away.

[anatole]

thanks for posting this Vince - we have an intermittent problem similar to this, will top reservoir right up and see if it goes away too!