92 firebird 305 auto. the trans has 108,000 and im sure its never been changed. my wife's mom bought it new in dec 91 and i just bought it last week. the trans fluid is dark but it shifts fine it will even chip the tires when it hits second. if i change the fluid i know i'll be losing some of the clutches friction material thats suspended in the fluid. i don't want to create a problem by changing the fluid. anyone change their trans fluid and then have a problem. opinions?

 

my tranny guy advised me to leave mine alone, since it has high milage and I don't know the history if its been changed or not....he said something to the effect that when you change the old fluid and filter to new ones...the pressure on the valve body increases...and breaks debris free that was built up on these surfaces, and causes it to clog passages, and possibilly ending the life of the tranny. He told me to just run it, and when it has a problem, wait till then to mess with it, then re-build it.

 

Just change the fuild.

 

"he said something to the effect that when you change the old fluid and filter to new ones...the pressure on the valve body increases...and breaks debris free that was built up on these surfaces, and causes it to clog passages, and possibilly ending the life of the tranny."
I have heard some nonsense before, but this is ridiculous. As long as the transmission is working ok, you can do a "complete" change, not a partial change of fluid.

 

anyone else?

 

he was refering to high mileage auto transmissions that haven't been serviced regulary....hes a vietnam vet that been working on transmissions in his own professional transmission shop daily since the early 70"s....so believe what you want but that my 2 cents...

but you emphisize the "complete" fluid change, as oppose to a partial change(the commom filter/4-6 quart drop the pan type of change most people do at home) your saying take it to a shop and remove all the fluid (the 12 quarts or so) from the torq converter and everything...like a total flush some shops advertise for $120 or so??? partial change bad....total flush good??? is that what you mean???

 

just drop the pan, change the filter, and refill. I had a 92 bird followed that routine every 100k and she lasted over 200k. Keep in mind I had the car in high school so it took a tremendous amount of abuse.

 

Yes, it is a total flush, but I would do it myself that way "you" know what got flushed. Remove the pan, and replace the filter with a oem type, and reinstall the filter, it must say "filtran", "microfelt", SP, or "Sealed Power" on the filter. Once this is done, disconnect the return line from the radiator (top) at the transmission and put it into a container. Fill up the transmission and start the motor, let it idle, and start adding fluid as fast as possible, once the fluid changes to the new color stop the motor, top off, and recheck the level, you should be ready to go.

 

what would you guys say is the best trans filter? what do you guys use??

 

It must say "filtran", "microfelt", SP, or "Sealed Power" on the filter. This is the oem filter.

 

Absolutely change the fluid and filter. Look at different filters, they are not all the same. I found that on older cars with high miles, a filter that has a screen instead of one that looks like fabric works better. The finer mesh filter tends to clog. I have never replaced an auto trans in any car I have owned, this is with 200k+ miles on them. If I use a deep pan, trans cooler and change the fluid and filter 1 a year, no problems.

 

the auto parts store i work at carries GKI brand trans filters and i've heard they're good. its what all the mechanics use...at least all the ones we deal with. never heard any complaints. where would you get "filtran", "microfelt", "SP" or "sealed power" filters anyway?

p.s. the trans only has about 27,000 miles since the rebuild so its not exactly high mileage...make any difference?