2007 Dodge Grand Caravan won't shift going uphill

My 2007 Dodge Grand Caravan with a 3.8L engine won’t shift going up hill. On any incline, it stays in the gear it was in when the incline starts and will never upshift. So we’re stuck going 20 to 25MPH up hill. Once we get to the crest of the hill, it shifts to the next gear and we’re good to go. From a standing still on flat land, if I nail the accelerator pedal, it also won’t shift, I have to back off the accelerator, and it will upshift normally. What’s up with this?

Have engine light on and the code indicates a bad EGR valve, and possibly a bad catalytic converter, but Autozone indicated that a bad EGR can also produce a code for a bad catalytic converter. They recommended replacing the EGR valve first, then see if the code comes back. But they didn’t know if this would cause a loss of torque, which might be related to the shifting problem.

If the EGR valve is stuck open, or the cat is severely plugged, you’d definitely notice it. You’d get poor acceleration, missing, rough idling, and stalling. Since you didn’t mention any of those symptoms, it seems unlikley the EGR or cat is related to the xmission problem. Still, it may well make sense to fix whatever is causing that problem before trying to fix the xmission.

There’s a couple of simple things you might ask your mechanic to try first. Make sure the fluid is reasonably clean and at the fill-mark. Consult your owner’s manual if you’ve never checked the auto xmission fluid level, as you have to follow a specific sequence to get an accurate measurement. And look for any signs of deteriorating rubber vacuum tubes that might be leaking, esp for breaks/cracks at the connections.

If somebody recommends an xmission flush, from what I hear said here, that’s probably not the best thing to do. It’s better to have a complete xmission service by-the-book done instead.