East Tennessee Mountain Grades & Winter Trucking Guide

The three big grades around Knoxville

Knoxville itself sits in the Tennessee Valley, but every interstate out of town eventually has to climb:

I-75 north: the Jellico grade. North of Caryville (Exit 134), I-75 climbs through the Cumberland Mountains to the highest point on the entire interstate, more than 2,000 feet, before dropping toward Jellico. Truck climbing lanes help northbound. Southbound, the long downgrades are hard on brakes.
I-40 west: the Cumberland Plateau. West of Kingston and Rockwood, I-40 climbs onto the plateau toward Crossville. It’s a long pull loaded westbound and a long descent eastbound.
I-40 east: the Pigeon River Gorge. East of Newport, I-40 winds through the gorge into North Carolina. After Hurricane Helene in 2024, it runs with one lane each way at 35 mph while it’s rebuilt, with full repairs expected around 2029.

Going up: protect the cooling system

A long climb with a heavy load means the engine works at high power while road speed and airflow drop. That’s where a marginal cooling system shows up.

Check coolant level and condition, belts, and hoses before the climb.
Make sure the fan clutch engages — a fan that isn’t pulling air is the most common reason trucks overheat on a grade.
Keep the radiator and charge air cooler clean. In the fall, leaves and debris pack into them quickly.
Watch the gauge. If it climbs past normal, ease off, use the climbing lane, and pull off when it’s safe. If it goes into the red, shut it down.

Coming down: protect the brakes

Pick the gear before the grade, not halfway down. A lower gear and the engine brake should hold your speed.
Don’t ride the service brakes. Constant light braking overheats drums and linings until they fade.
Know your adjustment. Brakes out of adjustment lose effectiveness fast on a long grade. Check stroke on your pre-trip.
Use the runaway ramps if you need them. They’re there for a reason.
At the bottom, if you smell hot brakes or see smoke, pull off safely and let them cool. Don’t set the parking brakes on very hot drums if you can safely chock the wheels instead.

What an East Tennessee winter does to trucks

Knoxville winters are mostly mild, which is exactly why they catch people out. A few times a year an arctic front or ice storm drops temperatures into the teens or single digits, and everything that was marginal fails at once:

Batteries. Cold cuts cranking power while a cold engine takes more to turn over. Weak batteries that got by all fall won’t start the truck.
Gelled fuel. Untreated diesel can cloud and gel in a hard freeze, waxing up filters so the engine cranks but won’t run.
Frozen air systems. Water past a worn air dryer freezes in lines and valves, and brakes won’t release.
DEF. DEF freezes around 12°F. Heaters handle it when they work; failed heaters and sensors show up on the first cold morning.
Brine and corrosion. TDOT treats roads with brine and salt ahead of storms. The spray corrodes trailer plugs, light sockets, grounds, and air fittings for weeks afterward.
Ice on the grades. Snow and ice hit the higher elevations — the plateau, the Jellico grade, and the gorge — before the valley. Check conditions before you commit.

Winter prep checklist

Load test the batteries and replace weak ones before the first cold snap.
Check coolant freeze protection with a refractometer, not a guess.
Service the air dryer and drain the tanks.
Change fuel filters and start using winter-blend fuel or an anti-gel additive before temperatures drop — additives don’t reverse gelling that’s already happened.
Check block heaters and cords if the truck has them.
Clean and seal trailer connections with dielectric grease to fight brine corrosion.
Pack for a wait: warm clothes, gloves, water, food, and a charged phone.

Fleets can have this done at the yard during a fall PM. See fleet preventive maintenance.

And in summer

East Tennessee summers are humid, with afternoons in the 90s. Combine that with a grade and a heavy load, and cooling systems, A/C, reefers, and tires all take a beating. Check tire pressures cold, keep the cooling system clean, and don’t let a creeping temperature gauge slide. See cooling system repair and truck A/C repair.

General information only. This guide is written for drivers and dispatchers working around Knoxville and East Tennessee. Rules change and every truck is different — follow your carrier's procedures, current FMCSA regulations, and the directions of the Tennessee Highway Patrol or other officers on scene.

Mountain Grades & Winter in East Tennessee