Is it better to get a automatic transmission flush or just remove the pan and filter and change the fluid myself. I know all of the transmission fluid does to come out when you remove the pan. Some say a transmission flush can damage my transmission. Is any of this true?
Yup, a flush can damage some cars. It is specifically not recommended on older cars.
A drain and filter job is much safer.
Quoting @russharv63 "I know all of the transmission fluid does to come out when you remove the pan."
Did you mean DOESN’T come out? That is the fact when you drop the pan. The fluid in the torque converter stays there. Getting it flushed doesn’t change the filter which could still be partially plugged. That said, I’ve had several cars flushed, old and newer, and never had an issue. It’s certainly better than no fluid change at all.
Drop the pan and don’t flush according to my trusted guy.
A flush should not harm the transmission. The problem is that it’s often done without ever dropping the pan, cleaning it while inspecting for any debris, and changing the filter first.
The reason why many shops may do the flush only is pure economics. There is much less time spent for the money involved on a flush only as compared to the extra time involved in a pan drop.
A fast moving shop can run half a dozen flushes through in the time that it takes one guy to pull a pan and go through that procedure.
It’s better to have a “Fluid Exchange” performed rather than just drop the pan change the filter and fluid. The reason being, when the pan is dropped and the fluid drains out only about 30% of the old fluid is removed. The rest is held in the torque converter. And if doesn’t have a drain plug it can’t be replaced. The old fluid can also remain the valve body and the cooler/lines for the transmission.
A transmission fluid exchange machine removes all the old transmission fluid utilizing the transmission fluid pump itself within the transmission. So it’s not a flush. It’s an exchange.
I have customer who has a 98 Camry she bought new. From the day she bought it, at the first 30,000 miles she just had the transmission fluid exchange done without removing the pan. At 60,000 miles she had the fluid exchanged and removing the pan. At 90,000 miles fluid exchange no pan removal. And so on. The vehicle now has 178,000 miles on it with the original transmisssion, and her son drives it back and forth to college.
We’re living in the 21ST Century. Some transmissions don’t even have a servicable filter. And some are sealed where you can’t easily check the fluid level or don’t have a removable pan.
If you want your tranny to last, treat it like your engine. And have the fluid “Exchanged” every 30,000 miles.
Tester
While it’s true a flush or exchange can replace all the fluid in a transmission, I always learned, and still believe, a pan-drop and filter change every 30K is sufficient to keep your trans fluid from breaking down. If that is no longer adequate, I’d be interested in understanding why.
Many of the flush machines use a “one-size-fits-all+plus+additives” fluids. Is that really what you want in your transmission? Some manufacture’s transmissions tolerate those fluids better than others.
How many flush places will actually drop the pan first to clean it and replace the filter - before doing the flush?
If you look at the automotive trade rags and see the ads for trans flush machines, the word “profit” is the overwhelming pitch for using those machines. You often have to look for the “customer benefit” wording.
If you’ve been keeping up with scheduled maintenance and your transmission has a drain plug, I’d just drain and refill, but I have a knack for screwing up gaskets when installing them. If you know what you’re doing, dropping the pan and cleaning the filter is a good idea.