Abstract: After losing lubrication, the planetary transmission system would transform into a system with temperature time variance characters. Any time temperature field can be attained by using transient thermal analysis. During the computation, the basic theory is that the pure thermal stream is equal to the increase of relative volume internal energy in the same point. Every time temperature field is computed by separating the time into series. Furthermore, the survivability of the planetary transmission system and the dangerous location would be predicted.

Key words: temperature-t ime-variance, t ransient thermal analysis, survivability