I know this has been asked before but I would like to get Ray O's take on this. I have an 01 Prism with 45,000 miles and would like to change the transmission oil. Some say that you should flush or all the oil doesn't get changed BUT this could stir up "stuff" that is better off not being stirred up. Others say to just drain the oil (remove the pan) and clean the pan and screen. What do you recommend Ray?
---MIKE---
At that time and mileage, I would just do a commercial tranny flush. That will back flush and clean everything with new fluid before refilling the tranny
mike hunt
---MIKE---
---MIKE---
**************** Since you are talking about a pan and screen, I'm assuming that you have an automatic transmission.At 45,000 mile intervals, you can drain and refill or have it professionally flushed, with the flush being a slightly better choice. If you were doing this for the first time at 60K or over, I'd drain and refill.
I asked my Chevy dealer (where I bought the car) and they recommend flushing. I asked the closest Toyota dealer and they recommend drain and refill but NOT flushing. The owners manual mentions changing fluid (but only under severe conditions) and makes no mention of flushing. I wouldn't mind paying the extra for flushing if it was the best way to go. But is it - or is there a risk of stirring up "stuff" that would be better off left alone?
---MIKE---
---MIKE---
With the relative low miles on your car, I would not worry about stirring stuff up and flush it. You should not encounter any problems either way.
I'd think that any stuff that was stirred up would be flushed out. That's why they call it "flushing," neh?
Geoff
You can do either - but IMO if the car is in good shape a simple drain and refill (check and clean the ferrous debris catch magnets, and change the filter if it has one) every 30K or so is plenty. That changes between 1/3 and 1/2 of the fluid, which is plenty to refresh the additives.
You pay a LOT more for a flush than a simple fluid change, and if the transmission has not been abused it's a waste.
If it HAS been abused by heavy towing or excessive loads, and the fluid looks and smells burned, that is when you do want to get it all out and a full flush is called for. Oh, and add a cooler, Now.
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Draining the transmission only actually "drains" 1/3 to 1/2 of the fluid?
Geoff
The Torque Converter stays full when you drain the pan.
The only ways to get that fluid out are to disassemble the transmission and drill a hole in the converter, or run the car and let the internal pump push new fluid in which forces the old fluid out.
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Not so. Commercial transmission flushing machines back flush out ALL of the old fluid, including the converter and filter, then it runs new fluid through until all the gunk is removed, before it refills the tranny again. Flushing is not interned as a 'repair' for a faulty transmission, but rather to function as a part of proper preventive maintenance regimen. If a tranny is problematic it is best to tear it down and effect a proper repair. If the purpose is preventive maintenance, the machines do a good job. I've seen flushing done on thousands of fleet cars over the years, and it works well.
mike hunt
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