I'm about to swap trannies to my '96 SE.I was told on higher mileage trannies not to change the fluid.If its working leave it alone.I had this happen on my '89 Reliant where I changed the fluid it quit running about a month later. Now. My friend who is more familar with trannies says is this is false. He always changed them with no probs. What are your opinions on this.

Thanks!

If it'* got 100k+ or so on it, I don't change it.

Is this a fact or your opinion & why?

Alot of people have indeed had problems with older trannys, with high mileage fluid, when they "flush" a tranny. And this seems to have carried over to changing it, I have seen posted that advice here and there. The best thing you can do for that tranny is drop the pan, change the oil, and replace the filter. But I would not flush it. Thats just going to bring up crap from deep inside every cranny and make a sludgy mess. Fact'* are a hard thing to state in the realm of a transmission that old. They are complicated pieces of machinery and so many things can lead to a failure. One thing for sure is older tranny with high mileage oil don't do well as an average.

Opinion. And I hold it because it'* what my ASE Master Tech step-father says to do.

I can understand your view Mouse given who gave you the advice. This old snake has been through his share of automatics, never had a problem just dumping and filling. A few seem to move better. A 76 Dodge truck with all but totally clogged filter was quite a big improvement. Like I said, Automatic transmissions can trash in many different ways, and not something your going to get "Facts" about. And mechanics are like Lawyers. You can line up 10 of them and get ten opinions. LOL

I've always done a drain, pan drop and filter change and never experienced anything other than smoother shifts and better performance through the power band. Having had friends that have done both the pressure flush and chemical flush, they have ended with major repairs or replacement because of internal parts. As Venom stated, the flushing usually moved debris and pieces and they get stuck in areas that restrict pressure or cause further damage.

What I have heard is it'* not a problem dropping the pan and changing the fluid and filter. But not to do a flush on higher mileage trannys. Doing this can remove varnishes causing leaks and slippage.

What would you consider high mileage? My 05 GXP has 71,000. I bought the car a few months ago and don't know if the tranny has ever been serviced.

Oh,how about 214k+ miles.I know,I know it should proably
have a rebuild.No problems with engine or trans currently.
Problem is the car I want to go into has only 123k with also
means it may have a stronger engine