Astra
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Subject: Automatic Transmission AF 14/20
Vehicles: ASTRA-F, VECTRA / CAVALIER, CALIBRA
Condition: Automatic transmission AF 14/20 switches automatically to the "Sport" program when under extreme loads. If the vehicle is subject to extreme loads (e.g. trailer operation under high ambient extreme temperatures), the transmission fluid in the automatic transmission can heat up to over 150°C/300 F. The "Sport" program can then not be switched off. If the transmission fluid temperature sinks below a certain temperature again in the further course of the journey, the AT controls will switch back into the "Economy" program.
Cause: hen the AT controls switch automatically into the "Sport" program and thus into a lower gear, higher engine speeds are attained. This reduces the difference in speed between the engine and the AT, caused by the slippage in the converter clutch. The reduced converter clutch slippage allows the transmission fluid temperature to sink.
Remedy: No remedy is required, as this automatic function protects the automatic transmission from overheating.
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