I have a 2001 Ford E350 with a 6.8L 10 cylinder engine. The tranny fluid has never been changed. I recently brought this vehicle out of retirement (parked for 4 years) to pull a 3,000 lb trailer I recently bought. When I ad the weight of my tools in the trailer, it weighs about 6,000 lbs. The tranny shifts just fine except it shifts hard going into 3rd gear. Otherwise, it shifts like a dream. So, should I change the tranny fluid and filter or just leave it alone?
I wouldn't change it. The new fluid can cause it to slip or have other issues. If your transmission is already having issues you can try draining a very small amount and add Lucas or adding new fluid in small increments
I worked on a Honda with 315,000 original miles, the transmission fluid was only changed 1 time at 45,000 miles. The transmission started slip and shutter so I explained the risk and decided to just do it .
I drained 1/4 to 1/3 of a qt at a time . I saved the old fluid just in case. I would drive the car for a few miles each time after adding new fluid. After exchanging 1.3 to 1.5 qt the transmission felt a lot better and didn't want to push my luck. Luckily it worked out for her and no real issues 8 months later.
You can trying doing it this way if you have no choice.
Perfect example of what can go wrong with transmissions with out proper maintenance. I was working on a Ford. The car had 227,000 miles on it. When I asked they claimed all fluids have been done in past. I did the fluid and filter and a week later I get a call saying the car isn't drivable. The new fluid was causing it to slip so bad it would take 10 seconds for it to finally go into next gear. It also had a really bad lash and shutter as well.
Thanks for the answer rob. Very informative.
That many miles you'd be tempting fate changing it
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