Most flush machines run hot solvent through the tranny and coolers.
I was waiting for someone to bring that up....yet another reason I refused to 'flush' a transmission system with one of those machines.
When you introduce a hot solvent into the unit and convertor you have just contaminated all of the friction material that the unit relies on to operate.
You have just screwed up the coefficient of friction that was engineered into the whole units design and now...how are you going to clean that mess up..?
You are not going to get all of that solvent out of the system and you have just thinned out the new fluid and shortened the life of the unit.
Not to mention the fact that the elastomer seals in the unit may be compromised by coming in contact with a
solvent..?
Would you pour a
solvent..? into your brake master cylinder..?
In an E4OD, and the 4R100 as well as virtually most any unit on the market today (except for dual clutch VW's) and since 1980 for GM, 1978 for Chrysler, and AODE for Ford the torque convertor has a clutch plate lined with a fiber friction material and also fiber friction material lining the clutches and bands...
What keeps the friction material from burning up and flaking off the metal plate or band it is bonded to is the fact that the material is highly porous and bathed in fluid.
When the unit is initally filled with fluid the plates are soaked and hold a certain amount of fluid until they are applied and then a certain amount of heated fluid is squeezed out...then the clutch plates are supposed to grip the steel plate next to it.
When the clutch is released...the friction material absorbs fresh, cooler fluid that is circulating around the drum...either inside it or outside...and the constant cycling of the hot fluid out and cooled fluid in is what keeps the friction material from scorching.
Manufacturers of friction materials spend an ungodly amount of time, energy, and money to engineer a certain coeeficient of friction to work with a vehicle manufacturers specicications so that their product will be chosen to become a preferred vendor for any particular transmission for any particular model year.
They have to constantly evaluate the performance of their product and modify it when it becomes necessary to comply with the OEM specs in order to not lose their contract.
This is why the OEM specify certain types of fluid...the fluid qualities and the friction material properties have to work together with the initial factory shift calibration and strategy.
Once you contaminate your unit with a
solvent..? you are not going to get it completely out of your unit, unless you run the unit with an endless supply of clean fluid for many miles and shift cycles...you would have to bottle-baby the unit much like being hooked up to an IV in the hospital with a contant drain hooked up to your uninary tract.
When it comes to a clutch or band apply and release in a unit...the rate of apply and release is monitored by the speed sensors and the data is fed to the ECM....The computer is looking for a change in rotational speeds after it commands a shift...you can have a ...
Crank speed sensor
Input speed sensor
Output speed sensor
And other monitored rotational speed sensors...
Once you corrupt the coefficient of friction in a unit the ECM will catch the change and attempt to adjust the acceleration or deceleration of monitored rotational speeds...some attempts will jack up the line pressure overall in less sophisticated systems and will adjust just the shift that it is most worried about in more complex systems.
If you are having trouble getting your head around the concept of coefficient of friction...do this simple demonstration...
Find a large flat pane of glass and lay it flat in front of you on a table and secure it so it will not move...
Wet your finger...probably your index finger will work fine...
Now...push down on the glass with moderate force with that wet finger and slide it along the surface of the glass untill you get a chatter or shudder feeling...
You started off with one coefficient of friction and ended up with another one entirely. The coefficient of friction constantly changed while the heat from friction evaporated the lubricant.
Back to the hot solvent issue ...
You may say that thousands of people have 'flushed' their transmissions with this method and suffered no ill effects...
I'm not buying it...
And I am not going to recommend putting hot solvent into anyones transmission that I might have to 'live in a fishbowl' with.
If you think that my concerns are not based in reality...call up any friction material manufacturer and ask to speak with their tech help and ask about apply rates, holding power, and release rates...you may find out more than you really wanted to know about transmission friction material.
Borg Warner
Raybestos
Allomatic
Alto
Schaeffler Friction Products
etc. etc. etc.
Lets talk about solvents...
What kind of solvent do you want to dilute your transmission fluid with..?
Kerosene
Petroleum Naptha
Varsol
Gasoline
Mineral spirits
111 tricloralethane
Brake Clean
Acetone
Paint thinner
Etc, etc, etc,
So...do we know what specifically the type of
solvent..? we want to dump into our precious, expensive gotta-depend-on-it-to get-to-work transmission today..? Do we know what the flush machines manufacturer recommends, specifically..? what is actually in the can that you are supposed to add with the 'flush' process...?
Lets get a quart of
solvent..? and pour it in and expect it to
improve...? our units performance..?
Basically the same thing...
But I don't know nuthin'...pay me no mind...