asb151

Thanks Rod R. I did check it for codes and there are none. Would a solenoid blockage/failure trigger a code? Thanks.

My truck just started doing this. In goes in and out of OD very quickly. Every 2 or 3 seconds.

I have a 2003 Z71 Silverado with a 4L60e (M30) transmission. The truck has 115,000 miles. Mostly highway with no towing. Tranny was serviced (flushed) at 30K and at 80K. Fluid level is good and color is normal. The issue is it shifts in and out of overdrive repeatedly if I climb a hill or put load on it. It only does this at a narrow speed range at roughly 45-50mph at 1200-1300rpm. If I am driving faster (on the highway for example) and I hit a hill it doesn't do it. All other shifting occurs normally during acceleration and deceleration. I am the original owner and I have never had any problems until now. Any help or suggestions would be appreciated.