I've been told that you should never flush a transmission, is this correct?
Do I really need to flush my transmission?
Your transmission is as important to your vehicle as the engine is, if not more so. Transmissions need to have the fluid changed in the same manner as your engine does, however it does not need to be changed nearly as often. Depending on the manufacturer guidelines and driving conditions, usually your transmission should be flushed between 30,000 to 60,000 miles. Over time, transmission fluid will degrade, which is accelerated by “hard use” or “severe driving conditions”. Minnesota is considered to be a severe driving condition state.
A full transmission fluid flush is vital as well, as opposed to a “drain and fill” which only changes out about 1/3 of the fluid. A full flush requires a machine that pushes all of the used transmission fluid out of the transmission, torque converter, transmission cooler, and transmission cooler lines.
If your vehicle has a serviceable automatic transmission filter, which should always be changed when doing a transmission flush (for the same reasons you would change the oil filter with an oil change). Before performing the flush, we drop the transmission pan and check for metal/clutch material etc to make sure the transmission is in good enough condition to receive the flush. If we find any chunks of metal/clutch material/etc, we simply reinstall the pan, top off the fluid, and advise you that the transmission is not in a condition where it can be flushed, and also advise that the customer will need a transmission in the future.
In the event (which is most of the time) that there is NOT clutch material/metal/etc. in the pan, we change the filter, install a new gasket, and reinstall the pan. We then proceed with the transmission fluid flush.
We then use a two part BG transmission flush/service kit to remove any buildup/varnish/debris etc. to completely remove all old fluid etc. from the transmission.
We then flush the entire system with our machine, pushing ALL of the old fluid out of the transmission itself, cooler lines, cooler, and torque converter.
Finally, we refill the transmission with fully synthetic transmission fluid and our BG Transmission conditioner which helps prevent future buildup/varnish from happening.
In the picture listed, this is the transmission pan out of a van that drove into the shop. Once we dropped the pan, we determined that the transmission was already too far gone, We cleaned the metal that was in the bottom of the pan, reinstalled the pan, and topped off the transmission. We advised the customer that this transmission could not be flushed.
This is why it is very important to have your transmission flushed. If you perform your transmission flush at regular intervals, it will give your transmission a much longer lifespan and will help prevent/negate failure down the road.