Towing into the mountains from Spartanburg? Six checks before you hit I-26

Head up I-26 past Landrum toward Saluda and Hendersonville and the road climbs for miles. With a camper or a loaded trailer behind you, that climb is where a tired cooling system or old transmission fluid shows up, usually far from home.

Here's what we'd check before the trip.

1. Coolant level and condition

A long pull under load is the hardest thing you'll ask of the cooling system. Top it up with the type your manual calls for, and if the coolant looks dirty or it's overdue, change it before the trip. The LLY Duramax is known for running hot when towing, and on a 6.0 Power Stroke, coolant problems sit at the start of a very expensive chain.

2. Transmission fluid

Heat wears out transmissions, and a mountain grade with a trailer makes plenty of it. If the fluid is dark, smells burnt or is past the severe-duty interval in your manual, change it first.

3. Fuel filters and the water separator

Drain the separator and check when the filters were last changed. A clogged filter can starve the engine under load, which is exactly when you need the power.

4. Know what your gauges should read

Learn your normal coolant and transmission temperatures on flat ground so you'll notice when they climb. If they start rising on a grade, easing off early costs you a few minutes. Pushing through can cost you a head gasket.

5. Plan the way down

The descent matters as much as the climb. Use your exhaust brake if your truck has one, pick a lower gear, and save the service brakes for when you need them.

6. Stay inside your ratings

Check the towing and combined weight ratings on your door sticker and in your manual. A trailer that's fine on flat interstate can be too much on a long climb.