Sojo40

Hey all,
I was wondering if I could get some info in regards to the 722.6 transmission making a lite whining noise when cold goes away when warmed. It does make just a very lite whine in-between shifts just after the end of the shift.
There is no slipping or delay engaging into gears. I am at 96000mi and wanted to know if doing a transmission fluid and filter change would help?
I been told it is the pump, if so how long do I have before it has to be changed and what is the dollars amount for the repair?
Also would a flush be the way to go or just the standard fluid and filter changed?
Experienced info would be much appreciated.

tusabes

Never ever do a flush

Only drop the pan and change the fluid and filter and the leaky electrical connector

Sojo40

Why not do the flush? I did here something about it can cause issues with the solenoid valves or of the like, what other reasons why not to do the flush?

tusabes

Your transmission pan is full of particles at the bottom. Just like panning for gold , they sit at the bottom until stirred up. Especially if it hasn't been serviced in a very long time

If you do a flush , you stir up all these particles and it is very very Easy for those stirred up particles to clog up and ruin your transmission. Many transmissions fail a few hundred miles after a flush because of this . Plus the filter is not changed when doing only a flush . If the filter gets clogged up , then too you may experience a failure . There's YouTube videos showing how transmission filters can get clogged and ruin the tranny

If you drop the pan and change the filter, you clean out all the particles sitting at the bottom before putting it back on.

Now the shops that do flush will tell you it's better because it change more of the fluid than just dropping the pan , but if you want to flush then what you should do is drop the pan , clean out the particles , change the filter, THEN do the flush to put in new fluid. But no shop does all that.

the real reason they do a flush only, is because it's easier they don't have to remove the pan and just hook up the flush machine from the top

Welwynnick

People say this all the time, and although my own experience DOES bear this out, I can't understand why it should be.

When you flush, you use the transmission pump to pull oil out of the sump, push it through the torque convertor and then the torque control valve, and then out to the oil cooler - which is disconnected to drain the oil. Fresh oil then comes in through the oil cooler return and goes into the sump.

The thing is - the oil path within the gearbox is exactly the same during flushing as it is during normal operation. Only difference is that clean oil is returned to the sump. During a flush, all the crud (and there's often a surprising amount) sits in the bottom of the sump and stays there, just as it would during driving.

So I'm not challenging the well known notion that flushing is risky, but just that we need to understand what's going on a bit better.

I rebuilt my transmission last year, and have a FAIRLY good idea of what goes on in there, but I still don't understand the risk of flushing.

Nick

tusabes

My understanding is that using a flushing machine is not the same flow or pressure as the fluid normally cycling through the tranny , and that the flushing process stirs up particles which are normally harmless and out of the way

ItalianJoe1

The flush machine itself isn't the issue. The main problem, is flushes done at most retail shops aren't using the right fluid, and because you aren't cleaning all the crud out, the new fluids with all that nice fresh detergent (trans fluid is an effective soap actually) moves all the crap that's been stuck in one place since new, around inside your transmission. This is what does the damage.

If you drop the pan, you aren't putting all new fluid for one, and you can put a new filter and clean all the stationary crud out of the pan. It's not 100% clean inside but it's way better than just replacing the fluid and hoping for the best.