Occasionalky Not Able to Stay in Second Gear

[Safari Wagon]

So I know some will jump on this opportunity to tell me that I finally blew my transmission by towing with a Camry... but hear me out first.

This minor issue goes back as far as I remember having the wagon - even pre-towing. Occasionally, when I am going up a hill and want to keep the car from upshifting to third, I move the shifter to 2. The "2" light on the dash does not light up and the car upshifts into third. It always goes into L (when I need it to) and does not upshift.

Any ideas on what the issue could be?
Thanks in advance for the input.

[Chris Crash]

First thing I'd check is the shifter linkage on the front of the trans. Clean it out real good. You never know!

[JohnGD]

And then check the neutral safety switch. Make sure the lever lines up correctly in each gear. And if needed check the electrical contacts with an ohmmeter.