Transmission Flush, To Do or Not To Do?

[jcogley1]

I've heard both point of views, (i.e. flushing may stir up problems). What is your opinion and if it is to do...at what miles?

[Lokim]

Flushing your trans. is never a bad idea. If it "ruins" the transmission, it was gonna give up the ghost soon anyway. I wouldn't let my fluid get past 15K, but I usually flush once a year.

[elwesso]

The term "flush" is so widely used that its hard to be conclusive..

The question I think you're asking (or should be asking) is... "Is fresh fluid bad for my transmission", and of course new fluid is always better than old fluid.. If its super bad looking, then you might need to change it 2-3 times before it turns out nice..

[BadQ45t]

You will know if your mechanic has a proper system if you require the full 15 or so quarts to refill. Hopefully you will not need to do it several times...but Lokim gives you the right information..there are always those people out there than flushed an old transmission that was not properly kept and you do one flush and the transmission buys the farm. He is right, you were done anyways. Flush it, refill with good fluids and cross your fingers.

[johnsy33]

My mechanic didn't recommend doing a pressurized flush on my 98 because of the age & only recommended dropping the pan & letting the fluid drain out for 30 minutes. There was a "sticking" feeling shifting from 2nd-3rd that started developing before the transmission service & now it has almost completely gone away. Thinking about doing it 1 more time soon just to make sure it's all new fluid & maybe that will completely get rid of that slight pause before shift.

[maxnix]

My mechanic didn't recommend doing a pressurized flush on my 98 because of the age & only recommended dropping the pan & letting the fluid drain out for 30 minutes. There was a "sticking" feeling shifting from 2nd-3rd that started developing before the transmission service & now it has almost completely gone away. Thinking about doing it 1 more time soon just to make sure it's all new fluid & maybe that will completely get rid of that slight pause before shift.

A pneumatically pressurized fluid exchange is never recommended. BG relies on the internal pump, Sun on a well regulated pump internal to the exchange unit.

Drain and refill is just adding new fluid to 10 qts. of contaminated worn out fluid. After about 6 consecutive drain and refills, you will get close to one mechanical exchange.

Be sure to drop pan , inspect, replace internal filter and O ring, replace pan gasket and use new one time use bolts.