lol, whoops... sorry bout that. yeah, I didn't catch the sarcasm

No wonder that sounded really weird to me...

 

You didn't use enough of the right smileys.

 

I don't think you actually understood what I wrote. I didn't anywhere say that heat in the transmission comes only from slipping clutches. It would be silly for anyone to say that the heat in a transmission only comes from one source regardless of what source they might choose

I did however mean that the failures I am talking about result from these parts rubbing against each other without a lubricant that can handle that, for whatever reason.

The clutches in these transmissions have quite a bit of controlled slippage on application and release in certain throttle positions and the torque converter clutch is modulated on lockup. This builds up heat pretty quickly in those particular places when it happens and if either the wrong fluid, or a correct but spent fluid is in there then things can go south really fast. For example, have you guys ever heard of clutch or torque converter chatter/shudder issues? Know what happens if one ignores that and keeps driving it like that for an extended time? I will tell you. The chattering clutch eventually burns up.

Do you know why Ford switched to Mercon V in these transmissions in the first place? Do you know what happens if you put the wrong fluid in one of these transmissions and run it for too long? IT was because they needed the right fluid in there to keep this from happening.

But, all that aside, I fully agree that an unlocked converter is the biggest generator of heat in general on any automatic transmission. No argument from me at all there. But, that definitely isn't the only place it comes from just as clutch slippage isn't either. Not that I ever anywhere near said it was though.

Aside from the heat generated on an open converter and the heat generated by controlled slippage of the clutch materials on both the transmission clutch packs and the torque converter clutch as they are being applied and released, there is still a lot of heat being generated. Wonder where that comes from?

Particularly with what has been said we need to keep in mind that there is still a lot of heat generated while the torque converter is locked up via the lockup clutch and is operating at a 1:1 ratio. I guarantee you that even if one was running down the freeway with good airflow across the cooler in overdrive with the converter locked up that a lot of heat is still being generated and disposed of. Even in that situation with a great external cooler that isn't running through the radiator at all, people are still seeing average temps between 150-170 degrees when everything is working properly. That heat there isn't from the converter beating up the fluid because the converter isn't beating up the fluid in that state. With the lockup clutch applied the connection through the converter becomes a mechanical connection instead of a fluid coupling. No whipping, cavitation or shearing is happening inside the torque converter when it's in that state. Yet, there is still this pesky heat coming from somewhere. Dammit all... WTF? :o

Also, when a clutch burns up why can/will only one clutch pack burn up (And heat up and toast the fluid in the process oddly enough. Wonder where that heat came from?) instead of all of them doing it or at least the rest of them showing some damage? I know you shouldn't and I don't at all agree with it, but I know people doing their own rebuilds often jsut replace the frictins and steels in a burnt up clutch pack because they don't have the proper tools to completely disassemble the clutch drum assemblies. If there were indeed bigger problems causing these failures then how do these guys get by with that?

These are the most common types of failures I see and these clutches burn up during slippage, for whatever reason, where the fluid either doesn't have the lubricity or heat handling ability to prevent them from doing so, again for whatever reason, and that is what I meant with what I said.

I take apart burnt up transmissions all the time where the clutch drums still work before I take them completely down. I test them beforehand to try and help me find out what failed. It would blow your mind how rarely there is an issue where the clutch mechanicals weren't doing their job. Usually there is only one clutch pack burnt up in the transmission unless the owner continued to try and drive it for a while after the failure and carried the contamination elsewhere.

I just threw out a huge pile of burnt up frictions and steels which would have made a fun picture. You can clearly see the hot spots on the steels from where the frictions were slipping against them. Which is again what I meant with what I originally posted in this thread.

So....

I meant exactly what I said and I stand by it to the point that I can keep aplying words to make it clear what I really said if need be. :santa:

Trust me, I am not doing anything here other than playing within the premise of this thread. Looks like it was designed to have a little fun. So I am not laughing at you, I hope I am laughing with you.

Did I use enough of the right smileys?

Darrin

 

the planetary gears create alot more heat then clutches that arent applied, but even then it only accounts for a very small percent of the heat made in a transmission. Cruising down the highway with the torque converter locked what keep the temp up is the oil-water cooler and planetary gearset heat. If you use the wrong fluid without the proper friction modifiers yes it will cause clutches to chatter and burn out.

 

Ok, I actually thought you were playing around but it looks like you arent and are instead serious.

I will quit joking, sorry.

I was joking but what I provided were actual facts. That is why I said what I said about taking the water to oil cooler in the radiator out of the equation. I have most people do that on the setups they get. As I said, they will still run about 150-170 degrees on the highway with the converter locked up.

As to where that heat comes from, it's true that part of it is from the planetary gearset, but most of it comes from the small clearances in the clutch packs allowing the clutch frictions and steels on the clutches that aren't applied to have slight contact with each other while everything is turning.

Have you ever had a clutch pack from an automatic transmission in your hand and tried to turn the hub that sits in the clutches? It ain't easy even with wet clutches. There is a lot of resistance. Better yet, have you ever tried to turn the input or output shaft on an automatic transmission that is just sitting there outside of a vehicle? That can be REALLY tough.

Why do you think you should never run an automatic transmission dry or tow a vehicle that has an automatic transmission without preventing the transmission from being driven by the output shaft? What happens if you do either of those is the transmission will burn up since there isn't fluid flow across those clutches that are actually still touching each other even though they aren't applied and the return springs have as much pressure off of them as will ever be. The planetary gearset doesn't get destroyed in those cases but the clutches burn up from lack of lubrication. If the planetary gearset was casuing all that heat then it would fry in that scenario and I have never had to replace a planet from people doing these things.

Again, I thought you were joking around as was the premise of this thread. Your replies indicate that you are not and with that, I honestly suggest that you do a little more research.

Seriously, I an sorry. I thought you had to be kidding.

Darrin

 

I change my tranny fluid and filter once a year. I just changed it last night actually. Now I usually use Castrol fluid for the tranny but I found Valvoline this time and bought it to give it a try since I use Valvoline oil. The Valvoline made a pretty noticeable difference. The truck doesn't downshift as much, it shifts smoother, and I don't have the shimmy between 45 and 50 anymore. So I'm pretty happy with the truck now.

 

Valvoline used to label their version of Mercon V as full synthetic. I am not sure what the real situation there is because they don't do that anymore. I also don't have any long term info on how the stuff performs. There may be a difference and there may not. I don't know.

I also had been a fan of Castrol. I used to use their oil pretty much forever until I switched to Mobil 1. But, I have seen some goofy issues on a couple of transmissions that used their version of Mercon V. I am not at all trying to say that there is a problem, I am just noting that there has been a couple of 'huh' moments for me with this. Hearing what you are saying adds up to another. I honestly don't know what to make of that.

Bottom line on fluids for me, all kidding aside now, is that you will hear me say "I don't know" a lot. Because of that I default to a full synthetic on vehicles that see extreme use and tell people to use Mercon V on everything else that calls for it. Which is most of what I deal with and that's why I mention it here. I know a lot of your trucks are supposed to run that too.

I will also tell you that you should never go wrong with the proper Motorcraft fluid for your vehicle.

Darrin

 

Also, whatever fluid you DO use, if you keep it cool, you won't have trouble. To me that means a temp gauge to establish NORMAL for your use, then an appropriately sized cooler. Plus regular service, of course.

 

A Scangauge can monitor tranny temps along with a lot of other things - and you don't have to install anything, just pop it into the OBD2 port.