Car mechanic warns Brits who drive automatic vehicles to stop making same dangerous mistake

A car mechanic has issued a warning to those who drive an automatic vehicle, revealing one mistake can completely 'destroy the transmission'.

American mechanic Scotty Kilmer has built up a huge YouTube following thanks to his car tips and tricks, with his popular videos racking up over 200,000 likes.

A mechanic has shared a warning to those who drive automatic vehicles. (Getty Stock Images)

In one YouTube video, the mechanic warned of five mistakes he tends to see often among drivers and urged people to think twice.

Driving through deep water

This can lead to water getting in the transmission and obliterating it.

Pointing to a small vent on his vehicle, Scotty said: "You never want to drive an automatic car through deep water and here’s why.

“You have to have vents on automatic transmission as the fluid gets hot and expands, and contracts to release pressure.

"If you go through water that will suck water into the transmission - water and automatic do not go together.

“If you get water in your automatic transmission sometimes you get lucky and flush it out - but often it will destroy the entire transmission and you’ll need a new one."

However, there was one mistake drivers make which can prove to be even more damaging to vehicles, especially automatics.

Going from drive to reverse while in motion

When this happens, the vehicle tends to stall and sometimes a slight grinding noise can be heard.

Most new cars tend to come with an inhibitor now, but for those who have purchased their vehicles secondhand, they need to be wary.

“Never accidentally have your car go from drive into reverse while the cars moving. Make sure you don’t accidentally hit it and rip it into reverse while you’re driving down the road because it will destroy the transmission," Scotty warned drivers.

One mistake can 'destroy' a car's transmission, the mechanic warned. (Getty Stock Images)

Leaving the car in drive

Drivers should always avoid leaving their car in drive if they are 'idling for a long time', according to the mechanic.

“Leaving it in drive if you’re idling for a long time [...] can lead to overheating of the inside of the transmission, if you going to be sitting there for a long time just shut the car off or at least put it into Park," he warned.

Doing burnouts

The mechanic also shared how damaging burnouts - keeping a vehicle stationary while spinning its wheel - are for drivers, and urged all drivers to do their best to avoid them.

Apparently, it's 'one of the worst things you can do for an automatic'.

Not replacing your transmission fluid

Scotty admits that manufacturers might argue that there is no need to replace the transmission fluid for some later car models, but he says this is a 'bunch of nonsense'.

"Yes, modern cars use synthetic fluid that can handle heat better and break down less, but eventually it does break down," he says.

"I still say replace your transmission fluid every 60,000 to 80,000 miles."