If the clothes are warm at the end of the cycle - most likely the problem is a clogged exhaust line and not the dryer.
Disconnect the vent hose from the dryer and run a load (or two) with the vent hose disconnected.
If the clothes are cold at the end of the cycle then the problem is a bad gas valve coils.
- The part number for the coil kit is
AP2150379
Here are the break down diagrams for the GE dryer
Model DDSS475GA0WW
Gene.