Flush or Change?


#1

When I took my 2002 Toyota Tundra in to a dealership for service recently to get the timing belt changed (a little later per the manual recommendation, but not too late) I was advised that I should get a transmission fluid flush and brake fluid flush.



My manual does indicate that those fluids should be changed at this time - this would be the first time and I’m the original owner… but “flushed”?



I told them to go ahead and change the fluids but I don’t want to pay for a flush.



Was I correct in doing so?



What increased benefit would result from a fluid flush as opposed to a simple change?


#2

You did the correct thing.
A trans flush that is not done by someone knowledgeable about transmissions can damage the trans. It is much safer to do a simple fluid and filter change unless the flush is being done by a transmission expert at an independent transmission shop.


#3

Different people make different decisions. Several years ago the Brothers were asked by a man who got a new car if it would be sufficient that every time he changed the oil, he pulled the transmission drain plug, take out whatever comes out and add new.

That is what do. Three quarts out; three new quarts back in. except I don’t do it every oil change.

Others have them flushed. Others take off the transmission pan and check the filter.


#4

There are two types of transmission flush machines.

One machine uses the transmission pump pressure to exchange the old fluid with new fluid by bypassing the transmission cooler. This is the good one, but it does not take the place of dropping the pan, and replacing the filter.

The flush should be performed after the pan has been dropped, filter changed, pan put back on, and transmission filled back up. Then the machine will be put on to replace all the fluid still left in the torque converter for a near 100% Transmission fluid change.

The other one is some type of power flush machine that may use cleaning solvents. I think that may be the one that people refer to as not good.


#5

Are there many or any shops who will drop the pan, change the filter, refill the trans, and then use the “good” style machine to finish the flush?

If there are any, how many of those will use a “generic atf fluid plus additives” rather than the correct atf specified for your car?

I agree in theory that flushing can be done correctly. But since most shops pushing flushes are out to make a quick buck, I doubt they’re worried about taking all the above precautions.


#6

Yup, but the typical drop pan, or flush service is about $100.00. The Drop pan, and flush combined is almost double the cost.

That service may be only necessary if the fluid has been neglected for a long time. You don’t want to mix new fluid with totally wrecked fluid still in the torque converter.

But if the transmission is service every 30K like it should then the drop pan, or alternate between the two is fine.


#7

The term Replaced, and flushed are almost used to mean the same thing in the automotive industry. I would not be surprised if the OP transmission fluid was replaced using the transfer machine, because technically its not a flush machine.


#8

Be careful that you don’t pay for what cannot be done on the car.

My wife’s '99 Malibu has a pan that can be dropped and a filter that can be changed.

My '04 Honda Civic does not have a transmission pan at all. The fluid drain plug is in the transmission case.


#9

A “complete” fluid exchange is more efficient than multiple pan drops. Do the arithmetic.

Just as an example, if you can get 90% of the fluid out of a 10-quart transmission/TC, you use 9 quarts. To get to 90% changing 50% each time (optimistic for a pan drop) you have to use over 15 quarts of transmission fluid. That would be over three pan-drops worth. If, as you say, it costs twice as much to have an exchange done, it is a bargain.