Whats the scare about Automatic Transmission Flushes???

[glockman25]

I got a 2002 pontiac grand am gt
and of course no dipstick to check fluid
Now i have heard so many horror stories about
transmissions going out due to dislodged gunk and crud
after the flush. Who has actual experience with this?
I have just heard rumors

 

[okiebryan]

If a transmission is starting to stall or slip, then putting brand new slippery fluid will make it fail. Every time. I have seen other neglected transmissions fail very soon after a flush. Conversely, I've seen transmissions go 300,000 miles on original fluid.

 

[Fyrtwuck]

How often should the transmission fluid be changed?

 

[Nilbog]

We hade a Chrysler mini van that had the transmission flushed. The tranny went out a couple months later. It was fine before the flush.

 

[PUMPKIN]

Not sure you can ever get all the fluid out of the converter to really flush it completely. If you cant "flush" out all the fluid it just don't make sense to me. i just drain and change the filter and refill. I guess flushing them washes out all the particulates that help the clutches enguage on an older tranny.

 

[BK7saum]

Flushes (for those that do them) are recommended every 30,000 miles or so. I typically run 75-100,000 and then have the transmission serviced, fluid and filter changed, etc.

Correct me if I'm wrong, but the flush pushes fluid backwards through the system dislodging all of the accumulated particulates from the filter and elsewhere in the system. Because you can't get all the fluid out (constantly mixing), you never get out all the trash that has been strirred up in the system.

 

[penismightier]

i just drain and change the filter and refill.

This is what I do.

 

[glockman25]

so why does gm seal trannies? will i get away with a filter and drain and fill? at 100k?

 

[4play]

Old fluid is contaminated with clutch debris and fine metal particals, along with broken down additives and poor viscosity. There is nothing in old fluid that has any benefit to the life of a transmission or how long it lasts.

Most if not all flush machines simply hook inline through a cooler line and they take out old fluid on one side of the line and replace with new fluid on the other side of the line. There may be a flush chemical (detergent) that gets installed before the fluid exchange and possibly an additive installed during or after the fluid exchange. I dont think any of the machines can run fluid backward since a lot of transmissions have check valves in place to prevent that, plus you would be working against the fluid pump.

 

[CHenry]

your tranny fluid should be clear red, when is subject to heat it burns and will take on a brownish tint. It should be changed immediately once this color change is found. I monitor trans temp with an after market gauge. I also monitor many other perameters. My trans temp never gets over 180 when I am towing my 10k lb. 5th wheel. When trans temps get above 200, fluid life is reduced and the hotter it gets the faster its reduced. You factory gauge wont tell you an exact temp so just monitor the color.