If you want a conclusive diagnostic performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a transmission shift diagnostic and the responding certified mechanic will get this resolved for you. If you canвЂ™t repair it on the car, just rebuild it.

The transmission you have is very common, parts are very readily available, and is easily rebuildable so you neednвЂ™t worry. Often, no 4th gear is accompanied by noise (due to hard parts failure) and/or 1st or 3rd wonвЂ™t work either. The problem with the overdrive and no 4th gear is probably mechanical in nature but would require further diagnosis. Transmissions 4.8L 2003 CHEVROLET TAHOE 4.8L 4WD 4L60E TRANSMISSION TAG ID 3KCD 2003 GMC PICKUP C1500 4.8L 2WD 4L60E TRANSMISSION Extended cab TAG ID 3CJD.

It is also possible to have inadequate line pressure due to a leaking boost valve, clogged EPC filter screen, failing EPC solenoid, or possibly leaky seals throughout the transmission. III+ engines.The 4L60E was concurrently produced along with its strengthened progenitors the 4L65-E and the 4L70-E. However, these versions have strengthened and improved components for the significant power outputs of GM's impressive line of Gen. If you see a big drop in pressure when the PCM commands 2nd gear, there is a leak. 4L70-E transmission is a further improvement still, and share most components. You can test for this by using an external pressure gauge. A more serious cause of 1-2 shift failure on the 4L60E is a leak in the 2nd gear apply circuit (servo assembly or 1-2 accumulator). Test the sensor (there should be a smooth, linear electrical response over the range of motion) or substitute a known good unit. The 1-2 shift failure on the 4L60E is often due to a faulty throttle position sensor (TPS).

Chevrolet transmission 4l60e