03/23/2023
. I never flush my automatic transmissions. However I do service them regularly, every 12,000 miles or once a year, which ever comes first. This involves draining all the fluid that will come out, ( I always install drain plugs in the transmission pans ) the pan is removed, and checked for particles, and worn friction materials. There is always a small amount present, an excessive amount would be cause for concern. The filter is changed, and the gasket replaced, and the pan is replaced with all fasteners torqued to the proper specifications.
If you try and flush a high millage transmission, you will most likely cause large amounts of sludge, and friction materials to come loose, possibly clogging the small passages, and screens, as well as jamming the various precision shift valves.
This might not happen every time, but why risque it !!! Just change out your fluid, as I described above, and keep driving your vehicle. The small amount of new fluid will gradually free up very small amounts of contamination, and gradually work it out of the system. Thus preventing clogging, and overloading the filter.
Getting back to a once a year, or 12,000 miles service interval will give you the best chance of having good service, and long life from your transmission, with minimal risque. Plus it’s cheaper in the long run than a flush !!!
