4l80e no overdrive

[Schurkey]

Are you sure it's a gear-ratio issue and not a torque converter clutch problem?

The converter clutch is locked-out if the computer senses misfire.

'97 K2500 7.4L. I "fixed" my transmission and my engine misfire by replacing a single cracked spark plug.

 

[NickTransmissions]

Anyone here experienced losing 3rd or 4th gear on their 4L80E 4WD Transmission? I have a 95 GMC Suburban K2500 and was reving at 3,000 RPM at 45-50mph with higher RPMs the faster I go....redline on my 454 motor is at 4,000. After i got off the freeway I restarted the engine and then shifted from 2Hi to 4Hi and back to 2Hi. This temporarily/permanently fixed the issue? Any idea what could have caused this?

I think everyone who has ever owned a 4L80E-euqipped vehicle has had some experience with losing 3rd and 4th gear or know someone who has.

Do you have any problems in Reverse at all (slipping, delayed engagements, etc)?

Also, did you shifting the transfer case from 2Hi to 4Hi and back to 2Hi after a power down and restart permanently fix the issue or just temporarily fix it? Can't be both.