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Transmission fluid replacement and/or flush

I have a 2002 Volvo XC70 with just over 75,000 miles. The dealer recommended a transmission flush (around $250). Is it necessary and what is the reason for a flush versus just replacing the slightly brown fluid with new transmission fluid?

If the fluid is brown, that is certainly not a good sign. It is usually an indication that the fluid was not previously changed as per the manufacturer’s maintenance schedule. It can also indicate that the transmission was subjected to overheating, which is also very injurious to the trans.

A simple fluid change will not remove all of the fluid from a transmission, due to the fact that the torque converter retains fluid that cannot normally be drained when the transmission is serviced. While I am not a fan of transmission flushes, in this case I would recommend that it be done in order to remove all of the burned fluid.

Just be sure to ask HOW they do their flush. It should include first replacing the transmission filter before doing the fluid exchange/flush. If the filter is not changed before the procedure, more damage will be done to the transmission.

Even though I do recommend a flush in this case, you have to bear in mind that it is not a panacea, and if the transmission has already been damaged by prior failure to change fluid on schedule, early failure of the transmission is still likely.

The dealer will clean your tranmission fluid and your wallet.
Check underneath the car, yes there is an underneath, for a drain plug in the tranny pan. Common on many newer makes. If so you can drain and refill with the RECOMMENDED fluid. Do annually or periodically until the color is reasonably close to new. Check with the dealer or independent to find out if a filter or screen is present in the tranny. Check your maintenance schedule for the service interval. My interval Accord or Merc 2005 is 20k miles or whenever color indicates. Merc has a filter, Accord not one Honda normally services. I service. Cheaper than a tranny overhaul.

Since it is slightly brown, You can do just a drain and replace. It won’t get all the fluid out, but it will add enough fresh fluid and additives to keep you going for awhile. Change it again at 90k and every 30k after that and the transmission should last as long as you care to keep the vehicle, and the next owner too.

Do compare the cost of a drain and replace with filter to the cost of the flush. I doubt the flush will be cheaper than two changes, but it might.