auto transmission

[Stefan Kondolay]

Ron,



Actually I mentioned Steve because he is a nice guy and would set you on the right path if you wanted to know. Believe it or not just because we are competitor companies does not mean if we don't exercise professional courtesy if our respected customers need a hand.



You have no idea about how extensive the technical background is for the company now recognized as DTT. Getting into that is not relevant to the topic at hand.



As we have in the past when you start along these lines said and repeat again, we are very happy that you are so pleased with your product and I am certainly not here to tell you otherwise.



SLDirks,



That is exactly the problem, there are guys out there who are sponsored and do not identify that affiliation. It makes it difficult for the average guy to figure out who is doing what.



The only thing to rely on in my opinion is information you can verify by either your service manuals, pressure gauges and or your own test driving different application trucks .



When you guys go to rallys drive as many different ones as you can, i know from experience the DTT customers are very willing to allow you to try their set ups, i am sure the other vendor customers may also be willing. The more trucks you drive the less chance you will be driving a sponsored truck and be able to check out various setups first hand.

 

[BillGotthelf]

Banshee-I can tell you do not have an engineering background.

Quick lesson in fluid dynamics. Two givens-one tc (A) has 3 times the surface area of clutch material than another (B), but both use same clutch material. If tc A has 60 lbs of applied fluid pressure and tc B has 90 lbs they should handle (all other things in trans being equal) the same amount of torque before slipping. You cannot use assumtions about the ability of a tc to hold a certain # of foot lbs of torque unless you can plug in alot of other numbers. As reported by some trans builders FACTORY transmissions vary in fluid pressure by as much as 25%. A poorly performing transmission with low line pressures with a 3 clutch tc will not work as well as one with high line pressures and a single clutch tc. Valve bodies alone will not help with low line pressures.

 

[Edward]

Here we go again :-{}

Robin

Someone who drives a transmission from company "A" posts a number and the stuff hits the fan. You would have thought that number was a fresh leg of lamb thrown out in front of a pack of starving wolves. No one from company "B" says a word about that number. No one from company "S" or "G" offers a challenge either. Apparently there is only one company and it's followers who have a problem with it. Robin you have a tough job and I respect that. But this pack attack is the very reason that one company I know of will not post on the TDR. I also know of another company who stopped positing because of the attacks. Robin please do not allow the pack mentality to demand censorship of statements simply because they disagree with them. If the pack is bothered with a post that is within the sight rules then they need to go pound sand.



Edward

 

[Bob Wagner]

Edward, for all you do this Buds for you

Originally posted by Edward

Here we go again :-{}

Robin

Someone who drives a transmission from company "A" posts a number and the stuff hits the fan. You would have thought that number was a fresh leg of lamb thrown out in front of a pack of starving wolves. No one from company "B" says a word about that number. No one from company "S" or "G" offers a challenge either. Apparently there is only one company and it's followers who have a problem with it. Robin you have a tough job and I respect that. But this pack attack is the very reason that one company I know of will not post on the TDR. I also know of another company who stopped positing because of the attacks. Robin please do not allow the pack mentality to demand censorship of statements simply because they disagree with them. If the pack is bothered with a post that is within the sight rules then they need to go pound sand.



Edward

 

[StakeMan]

If increased pressure makes a clutch hold better then why add clutches to the clutch packs?

 

[banshee]

Banshee-I can tell you do not have an engineering background. Quick lesson in fluid dynamics. Two givens-one tc (A) has 3 times the surface area of clutch material than another (B), but both use same clutch material. If tc A has 60 lbs of applied fluid pressure and tc B has 90 lbs they should handle (all other things in trans being equal) the same amount of torque before slipping. You cannot use assumtions about the ability of a tc to hold a certain # of foot lbs of torque unless you can plug in alot of other numbers. As reported by some trans builders FACTORY transmissions vary in fluid pressure by as much as 25%. A poorly performing transmission with low line pressures with a 3 clutch tc will not work as well as one with high line pressures and a single clutch tc. Valve bodies alone will not help with low line pressures.

Bill...



It is clear from your post that you have NO idea what you are talking about. I have no engineering background you say? Funny... I have a piece of paper from NC State University that says I have a degree in Mechanical Engineering, the State of North Carolina agrees that I'm a licensed ME, and the Dept of the Navy seems to think the same thing. FWIW, I work for what is regarded as the TOP engineering office in the Navy, and I'm sure that in the last year alone I've done more design, analysis, and engineering investigation than you EVER WILL, so put that in your pipe and smoke it. As far as the transmission goes, sit back and let me teach you a little about a clutch and multidisk clutch.



For a clutch, there are three and only three things that determine a clutch's torque holding capability: apply pressure, friction material (coefficient of friction), and disk geometry. The number of disks directly multiply the torque capacity of a single disk unit when the disks are stacked.



Starting with apply pressure or clamping force, this of course comes from fluid pressure behind a piston in our TCs. The truth is, it really doesn't matter at all where they clamping force comes from... it could be spring applied, piston applied, lever applied, or you could push it together with your hands... it really doesn't matter at all. The amount of force that is applied however is directly related to a clutch's torque holding capability, and I think everyone on this board seems to understand that fact quite well.



Moving along to coefficient of friction, this also directly applies to a clutch's torque holding ability. Obviously a "stickier" material will grab better before it slips. It sounds like a hell of a concept, and low and behold it's the truth. It's the marriage of these two ideas (clamping force and Coefficient of friction) that lead to the common formula that everyone loves to quote:



Friction force = Mu * Normal Force where



Mu (the greek letter) = coefficient of friction and

Normal Force = the clamping force



This is a great little formula for a simple block sliding across the table, but it is lost when looking a clutch. The third part of the equation, disk geometry, is the other major player in clutch disk performance. Disk diamter plays the major role in determining just how much torque the disk will hold before it slips. Let's imagine a ring 1" think in two configurations - one ring has a OD of 5" and the other has an OD of 10". The lever arm for the 10" disk is twice as long, so it is seeing less torque on the force of it's disk face and thus holds more shaft torque before slipping. It's the same idea as going to a larger gear in a transmission. The formula that describes clutch disk geometry is the following:



Area = Pi/4 (Do-Di) where:



Pi = 3. 1415

Do = Outer disk Diameter

Di = Inner disk Diamter



To apply all of this to a disk you first start with the applied claping force from the piston:



F=((Pi*Pressure)/4)*(D^2-d^2)



This formula applies to the piston in the TC and shows how much apply force is generated by this piston at a given apply pressure.



The torque holding capability for the disk is found by integrating the product of the frictional force and the radius of the clutch disk. After the integral, this formula comes out to be the following:



Torque = (F*f/3)(D^3-d^3/D^2-d^2)



Where:

F= clamping force from the above equation

f= coefficient of friction of the clutch's material

D= outer disk diamter

d= inner disk diamter



It should be noted again that this equation describes a single disk only, but the value for a multidisk setup is multiplied by the number of pairs of surfaces in contact. I would like to note that these formulas come from the book Mechanical Engineering Design by Shigley and Mischke on page 645 & 646 in the Clutches, Brakes, Couplings, and Flywheels section. If you'll notice, Bill, it's not in the Fluid dynamics section... that has NOTHING to do with a clutch's torque holding capability. Furthermore, as you can see from above, the numbers in your post do not even come close to making any sense whatsoever. How can a clutch with just 50% more apply pressure but 200% less clutch area hold more?? Is this some voodoo magic you have?? Finally, I'd like you to prove this statement with a little math:

A poorly performing transmission with low line pressures with a 3 clutch tc will not work as well as one with high line pressures and a single clutch tc.

Please apply it to the TC only... I don't think you can.



Chris,



Again, I'm saying that this TC does not have to be on a truck to show that it can hold the claimed torque value. Furthermore, math and theory go a long way as long as the example is represented clearly. Clutch design and analysis has been around a long time, and it's pretty much down to a science on determining how much a setup can hold. All I can say is make it slip, and then we'll talk about it.



John

 

[csutton7]

Banshee--do you know who did the test on the torque convertor--is the test ongoing--or was it just a one time test--put it on a machine and test it once and it held so this is the # it can hold--or has it been tested once a week for 52 weeks to see if it can really hold that much--that would be like if you sled pulled or drag raceed or even dyno'd numerous times in a given year with this setup and have 800hp then we will have a true test---I'm not saying it can't attain the 1740#, but can it do it over a prolonged period under true test conditions------I found out that the torque # came from someone else other than ATS and since they reversed engineered the t/c, which they were buying at one time, they were able to use this #, so the # is a true test # if we've been told the truth----again the bottom line is if you like what co. X provides you with then so be it--just do your research and find what suits you best---I'm just saying DTT is my choice because without them you wouldn't have upgraded Raybestos clutches or billeted or cryo'd parts, new stator design for excellent fluid coupling and a few other things---not that someone else wouldn't have figured it out at some point, but they were the first-----again do your research and pick what fits you best--for me that's DTT..... chris

 

[Boldt's Wagon]

Banshee: I agree with you. I previously made relative torque calculations for the 47RE clutch packs. The calculations were made for a single surface torque converter clutch and asume the coefficient of friction is the same for all clutch surfaces. I also assumed the front clutch was upgraded from 4 to 5 clutch discs.



The torque capability of the transmission clutches are proportional to the clamping force (piston area and hydraulic pressure), number of clutch surfaces stacked up, and average radius of the clutch face. The clutch area itself (a single clutch surface) has a minimal impact on the torque capability as the slipping force is the friction coefficient times the clamping force. Multiple clutch surfaces in a stacked disc array will multiply the effective torque capability. A larger average diameter clutch surface will have a larger torque capability as the slipping force (lbs) is applied at a larger lever (ft in the ft-lb torque capability).



Cutting to the chase, after calculating the clutch piston area and nominal clutch radius and then looking up the stock pressures and number of clutch surfaces the relative capabilities of the clutch packs was calculated. For the direct and OD clutch packs I also added or subtracted the 830 lb spring loading as applicable. The approximate relative torque capabilities are TC = 1. 7, Direct = 2. 4, OD = 1. 2, and Front = 1. This is with the front clutch upgrade from 4 to 5 clutch discs.

 

[banshee]

Chris,



Just so you know, I have absolutely no problem with the fact that you chose and like DTT, and never once have I said that they make crap stuff. The times I do get into these transmission debates is when someone posts some BS about ATS that is absolutely not true. The same is true with this thread, and I only got in it after your claim that they are lying. Again, I'll tell you that their converter has been in my truck for almost a year now and is holding very well with my ~1200 ft-lbs. That time includes plenty of drag racing, trailer towing, burnouts, and general abusive driving. At no time has it slipped, sounded like it was coming apart (or like it had loose converter bolts ) or performed poorly in any way. Everyone who rides in the truck remarks on how positive the transmission is and how well it works. ATS, not DTT, is the reason I have the transmission I do. DTT hasn't built a tripleock, but every other manufactuer of aftermarket TCs is going to that idea... . must be something to it.



With this remark:

I'm not saying it can't attain the 1740#

you seem to be agreeing that it IS possible to hold the torque they claim, and you're going against your raving post earlier that they're a bunch of liars. As far as the test goes, from my understanding it was an ATS in house test, and from the numbers & formulas it seems about right.



Finally, just what company are you referring to with this statement?

I found out that the torque # came from someone else other than ATS and since they reversed engineered the t/c, which they were buying at one time, they were able to use this #, so the # is a true test # if we've been told the truth

I don't think anyone has the design they do.



John

 

[banshee]

Bolt's Wagon,



Thanks man. It's good to hear all the calculations and theory worked out for you.



John

 

[tractorface]

Question

Since it looks like all the players are gathered here I have a question. I currently keep my OEM auto out of OD until about 50 MPH this means cruising along at 2000 +- RPM's and once I let it lock up I have to go about 60 to keep the r's up. I don't want to drive like this. I want to cruise at a lower RPM (quieter) Do any of the aftermarket auto's allow lower rpm cruising without damaging the trans. I understand that under a load I need to keep the engine from lugging but I want to drive to suit the engine not the transmission.

Help!

 

[csutton7]

Banshee--1200 lbs is not 1740lbs---what info you're giving is excellent real world testing up to 1200lbs---if someone has an 800hp truck to test the 1740lbs out that would be the best test we could get---otherwise we have to rely on a one time test under controlled conditions--not real world---yes it may hold to 1740 and above, but for how long---no matter who does the test we need real world---yes I'm now saying the 1740lbs looks to be a legit # from the originators of the triple disk t/c and ATS when it comes to their respective in house testing--



so on that front I owe ATS an apology and everyone else who has quoted this figure-I APOLOGIZE--still want to see it in the real world before I accept it as the 100% truth---



I'm assuming(trouble) that Precision was who ATS was buying their first components from as they supply many a transmission co with parts and that they are the original triple t/c guys--except for Ford of course----but I could be wrong about Precision it may be someone else---if I find out I'll let you know--



what we need is for someone everyone trusts to make some calls to the big time transmission supply co's and get some info and then a lot of stuff can be layed to rest----but I doubt again that we can get this info---would be interesting though to see what came out ---would end all transmission wars I bet-----chris

 

[banshee]

Banshee--1200 lbs is not 1740lbs

I agree 100%, but it's a start Now if someone wants to send the $$$ my way to get my truck to 1750 ft-lbs then I'd be happy to continue the test.

 

[banshee]

tractorface,



I've towed my racing trailer (fully loaded about 7500 lbs) with both my truck and my dad's truck (both ATS equipped) at lower speeds (below 50) while locked up in OD and cruising down the road with absolutely no problems. My 24V doesn't like to run with the revs much lower than 1400 rpms (about 45 mph), but dad's truck still makes monster torque down there and pulls very nicely with the transmission. Neither of us had ever had a problem with slippage or high temps when towing.



John

 

[Stefan Kondolay]

Tractorace,



It's advised to keep the R's above 1700, as durability on the transmission/OD will be greater. I see you said that you want to drive to suit the engine, if so 1800-2100 is where you want to be. Best fuel economy on my truck is achieved at approx. 1800

I would be looking at guys that have high mileage while towing at low RPM's.

 

[HoleshotHolset]

How does ATS address the issue of the multiple clutches dragging inside the TC? Is this not what causes the failures inside the F*rd TC's?



No flames intended.



Matt

 

[Snow man]

Tractorface,since you have a 24V,the sweet spot is closer to 2000RPM anyway,as for not wanting to hear the engine,you bought the wrong truck if you want quiet. I notice that not only is 1700 the minumum for the trans,the engine starts to moan,and the entire drivetrain vibrates the truck,it just doesnt sound happy at all when towing below 1700 to me. I love to keep the r's up,i keep 2000 minimum when towing,my engone sounds happiest at 2000 and above,so that where I run it. Matt, i was wondering the same thing about the triple disc TC,ATS says it has a higher coefficient of friction,and we all know what happens to triple dics TC s when they are in fluid coupling,the 2 rear frictions are dragging until the truck is shut off or in lockup. No flames intended here either.

 

[Un-Hemi]

So what? You have a whole bunch of other clutch packs and bands in the transmission that are running around in various states of apply and not-apply, and they are all contributing to the normal operating parasitic friction of the 47RE/H. I suspect that the additional losses of an unlocked triple-disk TCC would be INsignificantly greater than the parasitic losses of a single-disk TCC..... and non-existant when it is locked up.



edit: I thought I would clean this up, as I have been challenged on this particular topic before...

 

[HoleshotHolset]

I don't know about you, but most of the time when I'm going down the highway my transmission's clutches are all locked up... including the TCC. The amount of time spent going through the gears with certain clutches inside the transmission unlocked is minimal.



So why would it be advantageous to have even more clutches disengaged inside your TC when you are not in lockup?



Again - no flames intended.



Matt

 

[StakeMan]

Originally posted by HoleshotHolset

How does ATS address the issue of the multiple clutches dragging inside the TC? Is this not what causes the failures inside the F*rd TC's?



No flames intended.



Matt

I think the fords fail because the tabs wear through the thin metal of the TC.