no-reverse condition Archives - Transmission Digest
Diagnosing the Elusive No Reverse with the 4L80-E

Diagnosing a shift concern can be easy, as long as you understand some basic techniques to help get to the root of the problem. A reliable and orderly diagnostic approach is splitting the circuits. Splitting the circuits means separating and analyzing the hydraulic, electrical and mechanical issues that could create the problem. Let’s follow through the flow of diagnosis in this one together. Make sure you have the following on hand: a line-pressure-test spec sheet with test-port locations, and a clutch and band chart to help eliminate other areas that may be associated with the problem shift.