How many of you have "flushed" a high-mileage A/T with no prior service history?
What was the outcome?
What was the outcome?
High-Mileage AT Flush
- Thread starter The Critic
- Start date
Me:
2000 Avalon with 311,000 miles. The fluid is pitch black. Calls for Dexron.
No prior service history found except for a 3-4 qt drain/refill by me at the 290-295K mark.
Driver's complaint was: sloppy shifts once the trans is warmed up, presumably from deteriorated (sheared-down) fluid?
I performed a 12 qt "flush" using the new Maxlife ATF/CVTF. Drained the pan, drained the differential, exchanged 8 additional quarts of fluid via the cooler lines. The fluid looks pretty decent now.
I test drove afterwards and did not observing any shifting issues. We'll see how long it lives.
2000 Avalon with 311,000 miles. The fluid is pitch black. Calls for Dexron.
No prior service history found except for a 3-4 qt drain/refill by me at the 290-295K mark.
Driver's complaint was: sloppy shifts once the trans is warmed up, presumably from deteriorated (sheared-down) fluid?
I performed a 12 qt "flush" using the new Maxlife ATF/CVTF. Drained the pan, drained the differential, exchanged 8 additional quarts of fluid via the cooler lines. The fluid looks pretty decent now.
I test drove afterwards and did not observing any shifting issues. We'll see how long it lives.
- Joined
- Jul 11, 2014
- Messages
- 4,118
Plenty
Outcome... better and smoother shifting transmission
Outcome... better and smoother shifting transmission
140,000 mile Volvo 850 FWD with an AW-42. DEX III fluid. Never changed (Volvo doesn’t specify an interval on this car). Pitch black, slightly gritty.
Cooler line fluid exchange took 16 quarts to change it over to fresh fluid.
Flawless, smooth operation afterwards.
Cooler line fluid exchange took 16 quarts to change it over to fresh fluid.
Flawless, smooth operation afterwards.
All the time. Even the 500,000 mile Sequoia.
How much of the transmission was sitting in the pan?
Around 3 qt in the pan. Diff probably holds around 1/2 qt.
Unit holds 8.5 qt per the Amsoil look-up tool.
I misread your post - I thought you removed vs just drained the pan.
I was asking - how much clutch material was built up on the bottom of the pan and if it had mags how did they look- but you cant know so never mind
Yeah, I did not pull the pan. The plan was to replace as much of the fluid as possible, first, to see if the situation improved. Then we will do a pan drop and another flush after a few thousand miles.
I've never "flushed" a transmission but I've changed plenty of old ATF's. Nothing but positive results.
I did a Pan Drop, Filter and Flush on my 2016 Land Rover LR4 ZF 8-Speed Auto at 130,000 miles with no service history with the appropriate Redline Fluid and had no negative issues..
I did the cooler line fluid exchange method on my '03 V8 5 speed auto 4runner when I purchased it at 140k miles. Trans was working fine. Fluid was dark red and did not have that pungent smell anymore. I'm 99% sure it was the OEM fluid. I have the model that still used the T-IV fluid and has a trans dipstick. Pumped out 2-3 qts from cooler line and added equal amount of new fluid back in. 16 qts total. I used Amsoil signature series multi-vehicle ATF. Shifting became a little quicker/firmer after the flush. I did another fluid exchange around 220k miles, after doing multiple heavy towing trips of over 500 miles between 200k-220k. Amsoil fluid was still in great shape, just slightly darker than fresh fluid and still had that pungent smell. Currently at 265k miles and keeps going as it should. Pan has never been dropped, drain plug has never been opened either.
NEVER EVER Flush an automatic transmission. It's ok to do a fluid exchange that will not hurt your transmission. I'm not in the don't change the transmission fluid after X mileage. I can't tell you how many times I've been told don't change the fluid because of the miles on your transmission and ignored them all. When I changed out my fluid in my Volvo at 66K miles the service manager said you shouldn't and I ignored him. The fluid looked like chocolate milk and smelled really bad. When my transmission gasket needed replaced last year again the service manager at my dealer again said not to drop the pan and replace it just keep adding fluid. Yeah right I dropped the pan replaced the filter and gasket and buttoned it back up. Zero Issues ever and it has 140K on the clock. I did a total fluid exchange on my Prius about two years ago at around 95k miles on it and I've had zero issues.
Bought my TL with 120k on it and I don't know if it had ever had the fluid changed, it shifted like utter garbage, banging up and down the box. 3x D&F when it got home, and very regular changes ever since. Just turned 185K yesterday.
Simply - flush uses an external pump in a machine to force fluid through the transmission. Cooler line exchange uses the transmission internal pump to pump out fluid while you add fluid (via fill port, return line, whatever).
The thinking is that a flush can dislodge debris and damage the transmission, where an exchange is using existing flow direction and pathway, so dislodging debris and causing problems is much less likely.
The A541E is one stout-forgiving unit. Adjusting the TV Cable on a unit with so many miles is a good idea as I'm sure the cable is stretched a little.
Having a unit fail after a fluid exchange is an oversimplification.......
A. The unit was having issues beforehand & was going to fail regardless.
B. There is a lot of clutch debris in the unit & it settles in more places than just the pan,.....It's even permeates the pores of cast aluminum. Fresh ATF seems to move this otherwise harmless debris around & can clog up screens & filters or even jamb valves.
Never introduce flush chemicals into a transmission as it can amplify debris movement in the control valve body.
These picture are of a fully functional 4L60E, I wouldn't have had any reservations of exchanging the ATF on this unit, However....The debris collection points get worse & worse as the frictions wear. The screen in the second picture is known to clog on extreme high mileage units causing low line pressure & immediate unit failure.
Using a machine is still technically a fluid exchange, Introducing fresh fluid through the cooler return isn't much different than what happens during normal operation. In fact most machines don't force the fluid into the unit. The Cooler Out pressure forces a piston in opposition to a separate chamber full of fresh fluid. So the pressure is the same, It's just using the old fluid to push new fluid in.
Same with my Acura TL...
Transmission only had 60k miles on it and it was not shifting well especially when cruising and hitting the gas hard.... That was really really bad.
3 drain and refills... Does great now.