Transmission filter change help needed
Lexus Champion
Joined: Aug 2007
Posts: 4,507
Likes: 38
From: Bethlehem Twsp. Pennsylvania
Though my DIL's '99 RX has over 150K mi. on it with NO trans. problems so far, when I have done the complete change using the trans. pump, I have been concerned and amazed at the low pressure (or volume) produced when pumping the old oil out. I have pretty much always changed the complete system that way and have never seen that low a V/P on any other vehicle. I wonder if it is part of what is responsible for the failures that have occurred. This is one of the reasons I prefer the screen over the "paper" filter because I feel it tends to cause less restriction of volume.
the low pump pressure in the trans. has been a theory brought up on here once before. It probably is part of the problem. Thats why I used Wolf`s Head or Mobil-1 Synthetic trans fluid in my 01 for the added protection.
Lexus Champion
Joined: Aug 2007
Posts: 4,507
Likes: 38
From: Bethlehem Twsp. Pennsylvania
Last edited by lexus114; Jul 22, 2011 at 09:52 AM.
CL Community Team
Joined: Apr 2001
Posts: 16,531
Likes: 1,379
From: Austin, TX
I would urge you'll to think about the reasoning behind transfluid change.
If you want to capture the sediments, drain from plug is the way to go. If you are trying to change the new vs old fluid mix ratio, then suction pump is ok.
Nothing tops dropping the pan.
Salim
If you want to capture the sediments, drain from plug is the way to go. If you are trying to change the new vs old fluid mix ratio, then suction pump is ok.
Nothing tops dropping the pan.
Salim
Lexus Champion
Joined: Feb 2008
Posts: 1,709
Likes: 16
From: Ca.
Salim, The way I have ALWAYS changed the fluid (complete change) is to drop the pan, clean it and the magnets thoroughly, clean the strainer (or replace the filter and pan gasket in all other cars) and after re-installing the pan, add 4 qts. of fluid. disconnect the return line and have someone run it till there is a sputter of air and shut off. Add another 4 qts. and do the same thing. When you see the 1st sign of CLEAN NEW fluid come through, shut it off, reconnect the line, top off fluid and you're done. That IS a complete change and is the ONLY way I will ever do a trans service. I have driven Ford trucks for many years and was not happy when in the late '90's Ford eliminated the drain plug from the torque convertor. It was easy before that to do the complete change, just a little more work now.
Intermediate
Joined: May 2016
Posts: 483
Likes: 84
From: Indiana
I have done my own maintenance for decades now on all my vehicles (some 25+ by now) one of them is a 4runner 1999. There was a mforun member who discovered that not all transmission filters were equal. In fact, most of the aftermarket filters looked fine but upon closer inspection did not make a complete seal on the fluid inlet port. The trans filter is a suction port and even if the filter is bathed in fluid, if the filter is not sealed to the port, it will suck air, not fluid into the transmission. Some of the rebuilt trannys out there may have had an aftermarket filter installed and could fail again.
A way to test for this is to disconnect the cooler line and watch the fluid flow. Then over fill the transmission and see if the flow improves.
A way to test for this is to disconnect the cooler line and watch the fluid flow. Then over fill the transmission and see if the flow improves.
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