Transmission Leak Repair — Expert Service You Can Trust

A transmission leak is one of those problems that’s easy to ignore — until it isn’t. That small puddle of reddish fluid beneath your vehicle can quickly escalate into slipping gears, overheating, and eventually a complete transmission failure. Transmission leak repair is not optional maintenance; it’s urgent care for one of your vehicle’s most critical systems. At Mister Transmission London Dundas Street, Canada’s transmission specialists since 1963, our certified technicians diagnose and fix leaks before they turn into costly breakdowns.

Why Your Transmission Is Leaking

transmission fluid leak can originate from several places, and pinpointing the exact source requires professional eyes. The most common causes include:

  • Worn or cracked pan gasket — The transmission pan sits at the bottom of the unit and its gasket degrades over time, allowing fluid to seep out.
  • Damaged seals and O-rings — Axle seals, input shaft seals, and output shaft seals all harden with age and heat, eventually failing.
  • Loose or cracked fluid lines — Cooler lines carry fluid between the transmission and radiator; vibration and corrosion can cause them to loosen or crack.
  • Faulty torque converter — A crack or bad seal on the torque converter is a common source of a automatic transmission leak.
  • Damaged transmission pan — Road debris can strike and crack the pan, causing an immediate and visible leak.

Warning Signs You Shouldn’t Ignore

Catching a leak early saves you money. Watch for these indicators:

  • A reddish or brownish puddle under the centre or front of your vehicle
  • A burning smell while driving (caused by fluid dripping onto hot components)
  • Delayed engagement or slipping when shifting gears
  • The transmission warning light appearing on your dashboard
  • Low fluid level on the dipstick during routine checks

If you notice any of these signs, transmission diagnostics should be your next step — not driving another 500 km hoping the problem resolves itself.

How Mister Transmission London Dundas Street Repairs a Leak

Our leaking transmission repair process is systematic and thorough:

Step 1 — Comprehensive Transmission Diagnostics

Every repair begins with a free road test and multi-point inspection. Our technicians use professional diagnostic equipment to identify the exact source and severity of the leak — whether it’s a simple gasket or a more complex internal seal failure.

Step 2 — Transparent Estimate

Before any work begins, you receive a clear, written estimate. No surprises. We explain what needs to be done and why.

Step 3 — Expert Repair

Depending on the diagnosis, repairs may include gasket or seal replacement, pan repair or replacement, fluid line repair, or internal component service. All work is performed by trained transmission specialists.

Step 4 — Transmission Fluid Service

Once the leak source is repaired, we perform a full transmission fluid service  in London, Ontario — draining degraded fluid, cleaning the pan, and refilling with the correct fluid specification for your vehicle.

Step 5 — Post-Repair Verification

We road-test your vehicle after every repair to confirm the leak is resolved and the transmission is shifting correctly.

The Benefits of Professional Leak Repair

Taking your vehicle to a dedicated transmission repair shop  in London, Ontario rather than a general mechanic makes a real difference. Transmission systems are highly specialized — improper repairs can make the problem worse or mask underlying issues. At Mister Transmission, you benefit from:

  • 60+ years of transmission expertise — We do one thing and do it exceptionally well.
  • Specialized equipment — Tools and diagnostic software designed specifically for transmission systems.
  • Proper fluid specifications — Using the wrong fluid type can accelerate seal wear and worsen leaks.
  • Warranty-backed repairs — Our work is backed by a nationwide warranty, honoured at any Mister Transmission London Dundas Street location across Canada.

Regular transmission maintenance — including periodic fluid checks and changes — is the single best way to prevent leaks from developing in the first place.

Get Your Transmission Leak Diagnosed Today in London, Ontario

Don’t wait until a small leak becomes a major repair bill. Visit your nearest Mister Transmission location for a free road test and multi-point check in London, Ontario. Our team will identify the source of your transmission fluid leak and provide an honest recommendation. With over 60 locations across Canada, expert help is never far away.

Find a Location Near You ?  |  Contact Us ?

Frequently Asked Questions

  • How much does transmission leak repair typically cost? +

    The cost of transmission leak repair varies depending on the source of the leak. A simple gasket or seal replacement is relatively affordable, while a cracked pan or internal seal failure may cost more. Because pricing depends on the specific component and vehicle, Mister Transmission London Dundas Street provides a written estimate after a diagnostic inspection — so you know exactly what to expect before authorizing any work.

  • Is it safe to drive with a transmission fluid leak? +

    Driving with a known transmission fluid leak is not recommended. Low fluid levels can cause the transmission to overheat, shift erratically, or suffer serious internal damage in a short period of time. If you suspect a leak, check your fluid level immediately and schedule a transmission diagnostics appointment as soon as possible. Short trips to a nearby shop are generally safer than extended highway driving.

  • How often should transmission fluid be checked to prevent leaks? +

    Most manufacturers recommend checking transmission fluid every 30,000 to 60,000 km, though the interval varies by vehicle and driving conditions. Routine transmission maintenance — including regular fluid inspections — helps catch early signs of seal wear and degradation before a full leak develops. At Mister Transmission London Dundas Street , our free multi-point inspection includes a fluid check, so you always know where your transmission stands.

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Customer Reviews
Super impressed with the service...
Bobby Newton
Super impressed with the service provided by Peter. After going to a smaller transmission shop twice and never really addressing all of my vehicle issues. I decided to go to a larger chain. Peter seemed like he knew what he was doing from the get go. Truck is now running smooth. Definitely under promise over delivery. Highly recommend Peter
Date: April 16, 2026
Website: Google
Spencer was nice and looked...
Jarrett Hoben
Spencer was nice and looked at my car for free , told me my transmission wasn’t the problem very honest place
Date: February 3, 2026
Website: Google
I had an excellent experience...
Kenia (Ken)
I had an excellent experience with Mister Transmission and would absolutely recommend them. I originally took my car to a general mechanic who couldn’t find the issue and referred me to another transmission shop. That shop told me I would need a new transmission, with an estimated cost of $7,000–$9,000. After reading the great reviews, I decided to take my car here for a third opinion and to see if they could get me in sooner and am I ever glad I did! They quickly told me it didn’t seem like a transmission issue and offered to take a deeper look if I brought the car back as I had just quickly dropped in. When I did, they properly diagnosed the actual problem. It was such a relief to find out it wasn’t a transmission issue. Even though the repair wasn’t transmission-related, they were more than willing to fix it and were very upfront about my options. Peter, the owner, was incredibly kind and took the time to explain exactly what was wrong and how everything was connected. The service was honest, transparent, and completely stress-free. I’ll definitely be back and would trust them again without hesitation.
Date: December 16, 2025
Website: Google
I was there for a...
Peter Resko
I was there for a transmission service and I was very delighted with them. Professional people with knowledge.
Date: November 24, 2025
Website: Google
I brought my Nissan NV200...
Thames Valley
I brought my Nissan NV200 work van in, because I was having acceleration/power issues and what I thought was transmission issues. The owner Peter immediately recognized that I didn’t actually have transmission issues, it was in fact, a clogged catalytic converter rather than an CVT transmission issue. He then recommended me to the appropriate specialist that had me up and running again within an hour I was back to work! Super happy with the honest service and expertise.
Date: October 24, 2025
Website: Google
Good service and listens to...
Johnny1Leg
Good service and listens to the customer issues of their vehicle.
Date: September 4, 2025
Website: Google
Good service and listens to...
Johnny1Leg
Good service and listens to the customer issues of their vehicle.
Date: September 4, 2025
Website: Google
They listened to my concerns...
Scott Lupa
They listened to my concerns and preformed what I asked them to do. I was in and out in a few hours. Thank you. I would recommend them to anyone that needs transmission work.
Date: August 13, 2025
Website: Google
Brought my 2018 VW Passat...
GT
Brought my 2018 VW Passat in thinking I definitely had a transmission issue only to find out that it was something else. Spencer was excellent in explaining what was wrong with my car and couldn't be more friendly and offered to recommend places for the work to be done. I came away from Mr Transmission very impressed and would not hesitate to recommend them or bring my vehicle back again.
Date: July 17, 2025
Website: Google
Brought my 2018 VW Passat...
GT
Brought my 2018 VW Passat in thinking I definitely had a transmission issue only to find out that it was something else. Spencer was excellent in explaining what was wrong with my car and couldn't be more friendly and offered to recommend places for the work to be done. I came away from Mr Transmission very impressed and would not hesitate to recommend them or bring my vehicle back again.
Date: July 17, 2025
Website: Google
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