Transmission fluid is a core part of any car, and there are times when we have to get our hands dirty and change it. One mechanic decided to investigate the matter further by comparing transmission fluid after 35,000 miles with fluid that is brand new and has yet to go into a car.
A clip was posted on Facebook by a mechanic from Griffis Automotive Clinic Inc., an independent shop in Groveland, Florida. The video has racked up more than one million views, and there has been debate and argument from all sorts of people in the comments.
The mechanic was prompted to do the video as he and his shop believed it was a hugely important issue. Transmissions can fail, and the shop believed that this is down to manufacturer service intervals, which allow the fluid to become full of dirt and eventually damage the transmission.
In the video, we see two plastic bottles held up, both full of transmission fluid. It is easy to work out which has done 35,000 miles, and which is fresh and yet to go in a car. The mechanic hopes the video will be educational for many vehicle owners.
Comparing the New and Old Transmission Fluid
The video shows two bottles of transmission fluid together. One is in a bright cherry red color, while the other is a lot darker and looks almost like rainwater from a muddy puddle. According to the mechanic, the car’s service manual states that the old fluid came from a car that should be changed every 100,000 miles. Yet it is that color after just 35,000 miles.
He then held up a small valve next to the fluid. “Now, this right here is a transmission fluid temperature control valve. This is an aftermarket transmission temperature control valve,” said the mechanic. “This keeps the transmission fluid about 200 to 220 degrees,” he said, pointing to the stock valve. “This keeps it about 140 degrees,” he added while pointing at the aftermarket valve.
In short, the mechanic argued that manufacturers are running the fluid as hot as it can withstand in the transmissions, then telling owners not to change it until they reach 100,000 miles. This could lead to the transmissions being cooked, and ultimately lead to some major damage to the transmission itself. The mechanics expressed frustration that manufacturers say not to replace the transmission until 100,000 miles have been hit, yet that is the state of it after just 35,000 miles.
Why Do Some Say To Change the Fluid at 100,000 Miles?
The 100,000 miles between fluid changes is a bit of a grey area. Some manufacturers claim you can use the same fluid for the lifetime of the vehicle. In this instance, that clearly would not have worked. AAA has also said that for some vehicles, manufacturers recommend changing it between 30,000 and 150,000 miles. If the fluid shown by the mechanic is anything to go by, we should all be changing it at around the 35,000 mark.
Commenters on the video, perhaps unsurprisingly, were at loggerheads as to what to do. One stated they change the fluid at every 4th oil change on their lorry, and it has done over 380,000 miles. Another said that if you touch the fluid, your transmission will fail, but that is a very rare occurrence. Fluid in cars, be it for the transmission or engine oil, is meant to be changed at some point. We think that, to be on the safe side, following the mechanic’s advice is the best course of action.