I noticed with the colder temperatures my Jeep won’t shift into 5th gear until the transmission warms up, (about 5 minutes of interstate driving). It is an automatic (545RRFE). Also no codes, fuild changed about 3 months ago, and 75,000 miles on Jeep. Is this normal?
Yes. This is normal.
The drivetrain management system monitors both the engine coolant temp and the transmission fluid temp. Until both systems reach a certain temperature, the transmission will fail to shift into lock-up in the torque converter. This is done so the engine reaches the operating temperature faster, thereby reducing emissions.
Tester
Thank you