Had both Main and T/R chip lights
I have around 1600 hrs in 500's. Had both T/R chip light and Main Transmission lights come on. On 2 separate occassions T/R came on.
1st. Bearing let loose. We could almost get part numbers off of crap in Gear Box.
2nd T/R The bearing was turning on shaft making medal. I think it may have been nickle or iron. Can't recall the lab results. Replaced bearing and shaft on that one. The oil turned a dark brownish color.
On the Main Tranmission it was a silver paste. The gears were coming apart.
The RFM says Land as soon as possible when you get a chip light. I have never had a chip light come on when it wasn't a problem.