Engine/Transmission (1994 - 1998) Auto Trans and Triple Disc Converters

[Mark_Kendrick]

Bill K has talked about this a long time ago.

The clutch area in the torque converter is already larger than the front and rear clutches. Simply adding area to a clutch that is already large enough to not be a problem doesn't cure anything.

Production tolerances need to be addressed to save the trans.

This is what I believe he said.

These trans have three bad area's .

1 ) torque converter is way too loose.

2 ) line pressure is too low

3 ) production ( mass production ) is sloppy.



So, look at it this way.



Using a bigger chain to pull the truck out of some mud will do no good if the clevis pin is a 1/4 inch bolt!!!!

Anyway, buy what you want.

The clutch area in the clutch packs compared to a single disk converter is not a valid comparison.



After market trannies have extra clutches in the packs. When replacing only the valve body and TC the line pressures are increased to maximize the holding power of the stock clutch packs.



if you have a 5 disc pack increasing the line pressure 5% will give ~25% more holding power (5% more force per disc). 5% increase in pressure on a single disc gives only 5% more holding power.



So, even if a clutch pack has less total area it can hold more force than a single disc TC.



ATS did an exceptional job of explaining the concept...



http://www.atsdiesel.com/home/triplelok.asp



http://www.atsdiesel.com/atsu/atsu-lockupclutch.asp



from ATS's web site

Introducing TripleLok®

Many of our competitors also realized the torque converter problem and began trying to beef up their torque converters with more clutch surface area, hoping this would provide more holding power. A torque converter with more surface area will wear longer, however, it doesn´t necessarily reduce slippage or transfer your power to the ground. It depends greatly on how the surface area is being added. Go to ATSU Lockup Clutch section to learn more about lockup clutch surface area. With competitive designs the only way to increase static holding force (and thereby reduce slippage) is to increase the normal force by applying increased line pressure.



We liked the idea of a larger lockup clutch surface area to minimize wear, but didn´t want to have to use extreme line pressures or additional hardware to increase the static holding force. Our solution was to utilize the concept of a clutch-pack, which is used throughout automatic transmissions. By using a clutch-pack, the lockup clutch surface area can be increased without the need to increase line pressure.



With our clutch-pack design, the surface area is in three distinct planes giving THREE times the holding force of other torque converters. This is really important because having a robust lockup clutch system allows us to also optimize the design of the stator to match the torque curve of your engine and give you high torque multiplication. Other torque converter designs require the stator to be operational over a much larger speed window because the clutch system won´t lock up at low speeds. The stator in TripleLok® is designed to get you off the line with power, then to get out of the way for lockup at 30 mph. By using a stator design with high torque multiplication and a stall speed matched to the turbo diesel, and getting into lockup as soon as possible, we have the best of both worlds; good acceleration when pulling heavy loads and 100% efficiency with the early lockup.

http://www.atsdiesel.com/home/triplelok.asp



http://www.atsdiesel.com/atsu/atsu-lockupclutch.asp

 

[mjoppie]

i also would recomend greg long. he knows what hes talking about and he does things right the first time. awsome transmission guy. i wish i could afford a dtt, i wouldnt think twice about giving it to him to do.





matt

 

[Cooker]

The line pressure issue is a moot point. From what I have seen, depending on the performance level of the transmission, quite a few of the various vendors are using very similar line pressures.

 

[Mark_Kendrick]

The line pressure issue is a moot point. From what I have seen, depending on the performance level of the transmission, quite a few of the various vendors are using very similar line pressures.

Line pressure is not a moot point. If you use a single disc torque converter you must increase line pressures. At very high loads line pressures on a single disc converter must be such that shifts are harsh or may even result in snapping the intermediate shaft.



By building a mutlidisc converter you can set the line pressures to hold the neccessary load and give the desired shift quality. With a single disc the line pressures are driven by the force needed to hold the lockup at load.

 

[ndurbin]

I have had both a ATS and DTT TC and by far the ATS locked up harder (shook the whole truck). I haven't put many miles on the DTT yet as the truck has other issues, but it does not lock-up nearly as hard. The transmission w/ the ATS TC was built by Blumenthal (outta OKC). That transmission was the exact oppisite in the 1-3 shifts it didn't shift much better than a stock transmission, now in that area the DTT shifts much stiffer (I wouldn't say hard but stiff).



There are alot of different philosophies about how a transmission should work, I am not saying anyone is the best for the sake of starting a war, but you just need to invest in the one you believe in.



Nathan

 

[Cooker]

Line pressure is not a moot point. If you use a single disc torque converter you must increase line pressures. At very high loads line pressures on a single disc converter must be such that shifts are harsh or may even result in snapping the intermediate shaft.



By building a mutlidisc converter you can set the line pressures to hold the neccessary load and give the desired shift quality. With a single disc the line pressures are driven by the force needed to hold the lockup at load.

Mark,

You are certainly correct about the performance of triple disc converters and line pressures, I am not in disagreement with you on that issue.



My point is though that all high performance aftermarket transmission vendors, regardless of single disc or triple disc, are running very similar line pressures, including ATS, and this is is for the overall health and performance of the transmission and not the performance of the converter.



Since we (high performance transmission consumers) are all running similar line pressures as setup and/or suggested by our vendor of choice, the fact that the triple disc converter itself will function with lower line pressures is a moot point.



I apologize for not providing more details in my original post on the issue.

 

[Mark_Kendrick]

I didn't mean to get on your case either...



My point was that to make the single disc hold at lockup the line pressures had to be higher.



Last time I checked (it may have changed) DTT sets their stuff to unlock at WOT to save the TC. They rely on tight fluid coupling(89-9X %) to handle power. ATS goes the other way. . they have a lockup that will take what you throw at it.



It is the core of the difference between the two biggest makers of diesel transmissions.



Which gets back to the problem that Nathan Durbin had above. If an installer doesn't realize how to setup the transmission to use an ATS TC they will not have a happy customer.



My 2wd truck has a stage IV ATS... their basic rebuild plus a TC and VB. no Commander. The shifts are strong at my request. TC lockup feels like another shift. It works flawlessly.



I really want a commander but I spent the bucks on my 4x4 dually. It's getting a full tilt setup. Billet flexplate/input/drum/intermediate/output, standalone VB(converted from a 6spd), laptop interfaced controller , ATS deep pan... the works

 

[Graphic man]

i have spent a lot of years racing but have never got into Automatic trans. but i did go through a lot of converters to get the right stall converter for the car,

i have a full DTT with a ATS triple loc converter (long story)

i have never used a DTT converter but i can tell you the ATS converter will engage at 1000 rpm you can feel it, foot on brake and slowly bring up the prm's and at 1000 it engages, shifts 1,2,3 are very nice and, loc-up in IMO is harsh it will launch the truck and you need to back off the throttle, (its a good thing i ordered the good shafts) cause it feels like it could break the input shaft IMO .

when it goes into loc-up(under normal driving) the tach will drop to 1500-1600 peak tq. in a CTD.

the comp box on 5x5 will make this extremely harsh (except WOT)

the loc-up is better cause it will shift @ 2800-2900 and then drop down to

around 2200-2300 less tq. at higher rpm's

i am going to order a DTT converter this summer and try it in the truck just for my own piece of mind.



Scott

 

[fox]

As I read what is said, one company wants the pressure raised at all points , so all points hold better than stock.

Another company says that with one of their products you don't need to raise the pressure. What about the rest of the transmission?









I think many of us are challenging the rule book, so this is my last post on this topic.



Take it to P M 'S from now on.

 

[I-6DZL]

Last time I checked (it may have changed) DTT sets their stuff to unlock at WOT to save the TC. They rely on tight fluid coupling(89-9X %) to handle power. ATS goes the other way. . they have a lockup that will take what you throw at it.

Mark correct me if i'm wrong here, but you're saying that a tight converter is not a good converter ? If someone builds a tight converter why would you really care wether it's locked or unlocked. The fluid temp will get warm but not hot enough to discolor fluid or harm anything.

You may also be right that ATS has such a harsh lockup that it will indeed take anything you throw at it. But it will also take the input shaft as well! I'm not saying a DTT won't, but i've seen all too many ATS TC's break the poor input shaft. (knock on wood this doesn't happen to dads )



Why would you not want the best of both worlds??? A tight TC that will propell the vehicle harder/faster, and still take all the abuse you want to dish out at it.



Please tell me where i'm right and wrong... ... .



Thanks

Curtis

 

[Cooker]

Curtis,

When reading Mark's post I don't think he is saying that a tight converter is bad, but merely a different way of doing things.

 

[Mark_Kendrick]

Mark correct me if i'm wrong here, but you're saying that a tight converter is not a good converter ? If someone builds a tight converter why would you really care wether it's locked or unlocked. The fluid temp will get warm but not hot enough to discolor fluid or harm anything.

You may also be right that ATS has such a harsh lockup that it will indeed take anything you throw at it. But it will also take the input shaft as well! I'm not saying a DTT won't, but i've seen all too many ATS TC's break the poor input shaft. (knock on wood this doesn't happen to dads )



Why would you not want the best of both worlds??? A tight TC that will propell the vehicle harder/faster, and still take all the abuse you want to dish out at it.



Please tell me where i'm right and wrong... ... .



Thanks

Curtis

I didn't say harsh I said STRONG. If you can make the lockup clutch hold at reasonable line pressures you can set the pressures to fit the behavior you want instead of what you need.



A REALLY tight converter is only 93% efficient. that means that 7% of your power is wasted to heat in the fluid. at 300hp (crank) that's 21hp of heat. a 21hp heater is a big heater. A normal converter from DTT is 89-91% efficient. 45-55hp of heat for a 450hp truck.



Under heavy load (towing) you generate a lot more heat in fluid coupling than in lock-up. With an triplelock you usually don't need a transmission temp gauge because the transmission runs cool.



As for the DTT transmission with the ATS TC... the VB is probably mismatched with the TC. You might give ATS a call and see if they have a suggestion as to how to adjust the VB properly.

 

[Mark_Kendrick]

As I read what is said, one company wants the pressure raised at all points , so all points hold better than stock.

Another company says that with one of their products you don't need to raise the pressure. What about the rest of the transmission?









I think many of us are challenging the rule book, so this is my last post on this topic.



Take it to P M 'S from now on.

All companies agree that higher than stock levels are needed. The question is how much higher.



You have a lot more flexibility if you don't NEED drastically higher pressures. You can then set the pressures (within limits) for desired shift quality.



The higher the HP the higher the line pressures must be to prevent clutch pack slippage. What you don't want is the TC dictating the lower limit of the pressure range.



FWIW,

Mark

 

[Mark_Kendrick]

Curtis,

When reading Mark's post I don't think he is saying that a tight converter is bad, but merely a different way of doing things.

what he said

 

[DMorrill]

if you do heave pullying over10k and have over 450 hp yes triple. if not Dunrite converter is more than perfect for most apps.

i put one in and all is fie

i went through 4 trannys befor they isolated that the tc was tearing out the gears, and burnig u[p

 

[Jim Fulmer]

Last time I checked (it may have changed) DTT sets their stuff to unlock at WOT to save the TC. They rely on tight fluid coupling(89-9X %) to handle power. ATS goes the other way. . they have a lockup that will take what you throw at it.



I couldn't tell you how many times I've made locked shifts or locked it up under full throttle, as a matter of fact if I'm going to make a run under 60 mph I'll select 3rd and lock it up then hammer it to a 3-4 locked shift, I run a 91 converter and still have yet to have an issue.



Jim

 

[Mark_Kendrick]

You manually lock it though right? if so, that's not the way the transmission is 'programmed' to act but can be overridden. I've talked to bill before and he was dead set against lock to lock shifts. He is, or at least was, convinced they destroy transmissions. Several other vendors disagree.

 

[I-6DZL]

.



A REALLY tight converter is only 93% efficient. that means that 7% of your power is wasted to heat in the fluid. at 300hp (crank) that's 21hp of heat. a 21hp heater is a big heater. A normal converter from DTT is 89-91% efficient. 45-55hp of heat for a 450hp truck.



Under heavy load (towing) you generate a lot more heat in fluid coupling than in lock-up. With an triplelock you usually don't need a transmission temp gauge because the transmission runs cool.

Mark now that you've figured out how much HP is lost through a DTT in the form of extra heat generated. Do yourself a favor and figure that out for an ATS without a man. lockup switch or the commander.



How tight or loose does ATS build their TC's ?? Probably 80 -83% ?? That's more heat generated.



Under heavy towing i understand you generate ALOT of heat... ... . But a triplelock TC doesn't do any better to control the heat than a DTT. When unlocked both will produce about the same amount of heat. When locked both will cool as far as their coolers will them!!!



No argument is intended here, i just value others opinions and am trying to learn. It's clear you know your stuff about compounds, now teach me more about TC's, and trannies!!



Curtis

 

[Mark_Kendrick]

I favor the Commander. I've ridden in trucks with them. Duramaxes, dodges, and fords. Liked them all. Basically they are a speed activated mystery switch.



I just didn't want to spend the money on my low hp daily driver. I saved it for my dually.



The difference is that the triplelok doesn't ever need to unlock unless you are stopping. under lockup almost no heat is genereated in the transmission (only the heat caused by the pump circulating fluid/maintaining pressure).



With the ATS transmission the only time you need a heat exchanger (on a 94-02) is when you are hot lapping at the track. Staging generates a lot of heat and <15sec is not enough time to dissipate it. The transmission usually runs 'cold' even under heavy towing loads. the heat exchanger actually heats up the transmission fluid because the fluid is cooler than the engine coolant.

 

[Stefan Kondolay]

Mark,



If other vendor disagree (with DTT) that lock-up under gear changes will not hurt the transmission and some even offer and promote controllers to do this for everyday driving, wouldn't you agree that if the guys/customers break their input shaft doing this they should be covered. If not wouldn't it just be useless word disagreeing for the purpose of sales if your not willing to back it up.