Towing & Diesel Transmission Care: What Ontario Drivers Need to Know

Towing and heavy hauling put more stress on a transmission than almost anything else you can do to a vehicle. Whether you’re pulling a trailer through Southwestern Ontario or running a diesel truck for work, the extra load means extra heat — and heat is what shortens a transmission’s life. Here’s what our specialists want towing and diesel drivers to know.

Why Towing Is So Hard on a Transmission

Towing increases the load the transmission has to manage, which increases internal friction and heat. Automatic transmission fluid breaks down faster at higher temperatures, and once it does, it stops protecting internal components the way it should.

Auxiliary Coolers Matter

If you tow regularly or drive a diesel truck, an auxiliary transmission cooler is one of the most cost-effective ways to extend the life of your transmission. It’s a small upfront investment against a much larger repair bill down the road.

Fluid Intervals Should Be Shorter

Standard fluid change intervals assume standard driving. If you tow frequently, haul heavy loads, or drive a diesel used for work, your transmission fluid should be checked and changed more often than the general guidance in our fluid maintenance guide.

Watch for Heat-Related Symptoms

Slipping, delayed shifts, or a burning smell after towing are signs the transmission got hotter than it should have. Don’t dismiss these as normal towing behaviour — see our guide to transmission warning signs for the full list.

Diesel-Specific Considerations

Diesel trucks generate more torque, which the transmission has to manage on every shift. Combined with towing or heavy-duty use, this makes routine inspection especially important for diesel-driven vehicles — not just when something feels wrong, but as regular preventive maintenance.

Get Set Up for Heavy-Duty Use

If towing or hauling is a regular part of how you use your vehicle, talk to us about cooler upgrades and a maintenance schedule that actually fits your driving. Visit our Woodstock shop, our head office and largest service centre — we also serve Brantford and Simcoe — or contact us directly. More tips are available on our Transmission Tips hub.