February 07, 2008
Posted by twloesing

I have a 1999 Suburban, 7.4 liter and 4L80E trans. Having shift issues ?

Since moving to Texas from Arizona 2 years ago, the trans will not up or down shift in weather cooler than 40 degrees. It is in Safe mode from my scanner and will only operate correctly if the engine is shut off for a minute to clear the computer. It does not throw a hard code nor is my Auto-Xray scanner picking up any codes. I took my RV back to AZ in the summer and ran flawless. I believe it is electronics related. Any ideas ? ?