Transmission Flush -Good Idea or BS

called pep boys to have the ****** flushed in a dodge pu i bought. they said if it has more than 100000 miles on it they would not flush it ,so it sounds like there are some big drawbacks to pressure flushing a ****** with higher milage.

 

1st) Drain plugs on torque convertors?....'60's Fords with cast iron Cruiseomatics had them.

2nd) The home flush method works great. I've been changing transmission fluid and filter this way for many years on every vehicle I own. My OT Chevy Express van has 413K miles without a rebuild on its original 4L80E transmission.

 

THE ONLY THING I FLUSH ....is the TOILET.
"AND THE BOWTIE ROLLS ON"

 

we have been flushing trans for about 10 years in the dealer and i have seen 2 cars not move after. both had burnt fluid and the customers probably forgot to mention they may have some slippage from their trans. never have i seen a healthy trans fail or leak after a flush. i have flushed many high mileage transmissions without any problems. my truck has 88k on it and i wouldnt hesitate to flush it when it hits 100k. i just dont use the cleaner chemical that your supposed to run through the trans before the flush. i dont believe in snake oil type chemicals. and dont get me started on induction services or engine oil system flushes, what a load of **** those are. the only flushes i suggest are the ones the completely replace the fluid in that particular system. trans, steering, diff, coolant, and brake system. all fluids break down over time and need to be replaced.

 

amen to that.

i've never seen a machine that provides its own pressure for the flush (especially @ higher pressure than the trans was designed for), and if they are out there it seems like a really bad idea. Even though most of the manufacturers only recommend dropping the pan, i like to get ALL of it. It's cheap insurance.

changing the fluid CAN hasten the death of a transmission though if it's already got problems. But I guess if that happens, it wasn't much longer for the world anyway. When I was a tech I only saw it once; the fluid coming out was black like diesel oil and it smelled like hot tar. The guy was pretty mad, he told me if I knew what I was doing he wouldn't have had to replace his transmission. Haha.

 

Easiest way to do it yourself is buy a (10 gallon) 20lt drum of quality auto transmission fluid, more cost effective this way and you have some left over oil if needed. Also get hold of a large engine oil change bucket and another external transmission fitting with a 45cm length of hose.
As an example, a 700R holds approximately 12lts of fluid, the transmission and pan hold approximately another 4 1/2lts with the remainder in the convertor. If you run it through the radiator and an auxiliary cooler you'll uses a little more fluid.
I'd suggest putting the car up on jack stands and running the engine to warm up the oil so it thins out and flows easily. Next drop the pan and catch all the old oil in the bucket. Next drop the pan and change the filter, add a new gasket and bolt it all up again.
Add 5lts of fluid through dipstick and then disconnect the (Pressure) outlet and screw in the fitting with 45cm of hose and have the bucket handy. The top fitting (T700) is the return line and there is no need to disconnect it.
Next, start the car and let it idle, DO NOT REV IT Be mindful that the bucket needs to hold approximately. 6lts of fluid.
As the engine idles, the transmission will pump the old contaminated oil out into the bucket. As soon as it starts to splutter, turn the engine off as the old contaminated oil has now been displaced and replaced with clean fresh fluid.
Next reattach the pressure line to the transmission and add a few more litres through the dipstick tube before starting the engine. When you do start it, run the transmission through the gears to get the pump working, pressurize the system and displace any remaining air. Once you've done this, check the fluid level on the dipstick and voila, it's done. You'll have to top it up of course.
The bucket and hose make it easy to do rather than having old oil spray everywhere. Keeps everything clean and you don't have much to clean up after
I purge my system ever 15K miles for optimum maintenance, change the oil and filter.
New fluid is pink, red means used and brown or brown with red means it's been too long. If you drive hard or tow, do it more frequently. A magnet in the pans helps to get all those metallic particles and stop them circulating doing more damage. If the filter clogs it can cause the pump to fail due to fluid starvation. Remember a transmission runs between 180-250F, pull a hill or tow and it will increase. Anything near 300F for any period and it may toast the transmission.