[Huskymaniac]

Originally Posted by NiftySVX

I understand what you are saying about the fluid, but keep in mind that the clutch is going to slip regardless of the temperature of the fluid. The fluid can be 0 degrees or it can be 212 it won't make any difference. Once the clutch slips it will boil the fluid off the friction surfaces no matter what temperature it is. The problem is that there is not enough fluid, or that the fluid didn't drain fast enough, depending on the circumstance.

So would improving flow by putting in a less restrictive cooler help get enough fluid in there to prevent slippage? How much heat do those plates generate in order to take a fluid at 0C and instantly boil it?!?!?!

ATF and the transmission are designed to operate between 176 and 212 degrees. The best thing you can do is make sure the fluid is changed regularly as needed.

So are you saying that a healthy transmission does not have a slipping clutch pack and, if I change the ATF regularly, it probably won't start slipping? Of course, I am also assuming that I can't beat on the car, which I don't and won't.

ATF is stable to about 300f. You will never see it get that hot though, the hoses and seals would melt out long before that. The new TCU turns the light and enters overtemp mode at 212, which you will still never see, unless the fluid is overheating because a clutch pack is slipping, and at that point you don't need a light to come on to tell you your trans is shot. Or because you have overfilled it.

Let's assume that we only have the stock cooler in the circuit. I believe it is normal for the engine temp to rise into the 190s and even a little higher in hot environments and stop and go traffic or on a hill climb. Won't that heat the fluid up to the 190s, or higher, as it goes through the stock cooler which shares the same radiator as the engine coolant? And, if it starts that high, won't the ATF temperatures rise well into the 200s as it passes through the tranny?

The rest of the modifications you mention will have effect on the operation of the transmission but will be highly unlikely to have any effect to extend the life of the unit. This is debatable, to some extent, but no modification to the resistor in the solenoid A circuit or to the shift maps is going to make a serious difference.

As far as synthetic fluid goes, it's a waste of money in my opinion. Again, it won't do you any good when your line pressure is too low and the clutch slips. The best fluid in the world won't do you any good at that point, unless they can come up with one that repairs friction discs

OK, I got the message about a slipping tranny being beyond repair short of an actual rebuild. But, assuming it isn't slipping, won't a resistor increase cause the line pressure to be a little higher and help avoid a slip from developing?

On synthetics, won't using them also help to avoid developing a slip? Actually, what really causes a slip to develop? You mentioned earlier that not enough fluid or the fluid not draining fast enough is the root problem. If that occurs, what mechanism then causes the clutch discs to start slipping? I was under the impression that the ATF fluid overheats. That causes it to oxidize. It then either loses its ability to lubricate and/or it starts to coat the tranny parts with crap. The crap then causes it to slip. So, if one can keep it from overheating the fluid, one can help to avoid this chain of events. By overheating, I mean the level of heat that causes the tranny fluid to oxidize rapidly and not the crazy heat you mentioned once a slip has developed. I picture this as a vicious cycle that has to be broken or brought under control. The ATF heats up which causes it to oxidize which causes it to not lubricate as well which causes the tranny to generate more heat which causes the ATF to heat to an even higher temperature and so on until the temperature gets so high that parts start to get coated with crap from the overheated ATF.

Changing the fluid regularly will keep fresh, non oxidized, fluid in there to keep things lubed properly and keep the temperature from ever getting to that critical temperature. I would think synthetic fluids would oxidize slower so it will stay fresher between ATF changes and keep one from getting to that critical temperature. Also, ester based synthetics supposedly help heat transfer to keep temperatures lower. Cooling the fluid better, with a better external cooler, should also help slow down this process and keep one from getting to that critical temperature. And, of course, getting better fluid flow would help since it helps to keep parts cool and avoid the overheating based oxidation in the first place. As you and Tom mentioned, the valve bodies would help there along with, perhaps, a less restrictive cooler.