[V8] 1990 V8 auto transmission issue

[Professor GT gmail]

Hmmm, I feel the urge to continue this rant, and I must say, Alan is right on the money regarding maintenance. 

Please allow me to digress and impart some greatly valued knowledge I've picked up along the way. Just the facts, no fictitious "Urban Legend" here.

"Filled for Life" with respect to auto trannys is an oxymoronic statement/concept.

ALL lubricating oils oxidize! Even synthetics oxidize; by design they are just much more resistant (not immune) to it.

Heat is one of the main catalysts that accelerates the oxidation process. As the oil (fluid) oxidizes, it loses all those properties it was designed to perform for us. In the case of tranny fluid there are seven, yes, count 'em, SEVEN main functions the fluid must perform:

1: Lubricate - (the obvious one, and with many folks the understanding stops here) Not only does the fluid deal with shear loads between gear teeth, but it cushions shock loads that would prevail with dry friction contact. We'll get back to shear later, one of the largest contributors to viscosity breakdown.

2: Cool - the fluid carries away heat and exchanges the heat energy to ambient air through the tranny cooler. Ever heard the name Hayden? They made a very successful business from offering well made add-on tranny coolers that have saved many an auto trans over the years! Tow a trailer - add a cooler! There's a balance though  as too cool is not good either.

3: Transmit Torque - through the torque converter the fluid provides hydro-dynamic energy transmission to the gearset. The fluid viscosity is obviously critically important in this area as it must be viscous (thick) enough to transmit torque between the impeller pump to the turbine blades in the torque converter, and yet not be too thick as to cause undue hydrodynamic drag.

4: Provide a hydrostatic energy transmission medium for hydraulic control system functions (valve body), through the use of its many spool &, control valves and solenoids.

5: Clean - the detergent additives not only clean parts, but the emulsifiers break contaminants up and hold them in suspension so they can be removed when the oil (fluid) is CHANGED - Hello, it's called Maintenance! LOL!

6: Seal - the oil contains specific conditioner additives that maintain pliability of seals, and the oil itself helps the sealing process occur.

So, you may be thinking, "There's more?" Yup! Come on all you gear-heads, what's number seven?

What do you do to a nice chrome-moly part like a turbine shaft to keep it from oxidizing (rusting)? That's right, you coat it with oil!

7: Corrosion Inhibitor - the oil must remain on parts, coating them even for extended periods of rest, so that internal parts do not suffer the negative effects of oxidation. Corrosion inhibitors allow a film of oil to serve this purpose.

So there you are, all seven functions of a modern auto trans fluid! 

What good is knowledge if it's not shared openly?

True knowledge shared openly eats Urban Legend for lunch!

So, to continue the "rant" from a perspective of sharing knowledge, why would any company advertise "Filled-for-Life" (FFL)? A few reasons actually, all of which can be traced to the "tail wagging the dog!" This begs another question, no pun intended. What happens when there's not enough car guys in the car business? Ah, now were getting to the bottom of the matter. You see any real "car guy" knows this stuff, and realizes therefore that machines need service. There's no "free ride"! No maintenance = breakdown, period!

So, when others (non car guys) win, things like, "Oh they won't buy our car if we tell them they have to spend money maintaining it, so let's just tell 'em it's "filled-for-life"! And I'll bet the Yo-Yo who came up with the idea was promoted up the NCG (Non-Car Guy) ranks faster than you can say "out of warranty failure"!
Or, there's the other really lame approach in trying to claim being more "environmentally friendly" by claiming FFL! Hey genius, it's oil. It came out of the ground to begin with! 

So, how about putting the used stuff back down there in all those "empty" wells! Well, maybe we can't be that extreme, but it's a thought anyway.

Back to oil. 
Does oil wear out? 
Wadda ya think? ..............................

Answer is a definite Yes! 

To create a multi-viscosity oil, like a 5W-30 for example, VI (Viscosity Index) improvers are included in the additive package. VI improvers are long chain molecules of high molecular weight. These chains uncoil and interact with each other as temperature rises to allow a base-stock 5 weight oil to behave as a 30 weight at higher temps.
The shearing action inherent to passing through a low clearance/tight tolerance mesh of gears for example breaks these chains into smaller pieces, thus the added viscosity at higher temps available through the use of VI improvers begins to degrade almost immediately, although at a decreasing rate, until the oil reaches the viscosity of the base stock. 

This coupled with oxidation are the two largest causes of lubricating oil degradation. 

Oxidation, just like rusting (the chemical combination of a molecule with oxygen), occurs over time even in an enclosed container, and is a function of the amount of oxygen present, and catalysts, the most important of which is heat! Oxidation inhibitors like anti-oxidants are added. These additives actually sacrifice themselves to the oxidation process, allowing the base oil to remain unaffected for a longer duration.

Next question: which is worse, underfill or overfill of an auto transmission?

Because of heat induced oxidation, overfill is much worse for an auto trans. While an engine will destroy itself as it continues to run without oil, a auto trans will cease to operate. In an overfill situation however, the oil level reaches the rotating components where it will be churned, adding both oxygen and heat to the equation! As the oil very quickly oxidizes, all seven of it's operating function also quickly go out the window, and catastrophic failure is guaranteed.

I can spend an hour talking about synthetics, but I'll save you the dissertation on that one. Just understand that for ultimate protection, full synthetics are the real deal!

With respect to "additives", NOT! If you use an "approved" product it already has all the needed additives, and using more may actually be harmful as it throws the chemical balance off!

Flushes? Again, if proper maintenance is done using the proper fluid, flushing just flushes more of your hard-earned cash, you know where!

So, bringing this rant/knowledge dump back to the starting point, Alan is "The Hammer" that hit the nail on the head and drove it home in one shot! 

Do your maintenance and prosper!
Bravo Sir Alan!

Hope this was enlightening, and saves you from some of the "Flushsters" out there who want to take you money. Tell 'em you get all the flushing you need, .................... in the bathroom!

OW-D On!


ProfessorGT
(Sent from my iPhone4)