Torque Limiting

[RustyJC]

Now the transmission tells the ECM what it's doing and the ECM controls the enigne, the transmission control module has nothing to do with controlling the fueling.

Using typical controller logic, the interplay between the modules might go something like this: the transmission control module (TCM) would tell the ECM that a slip condition exists. The ECM would then proceed to reduce torque until the slip condition is no longer reported by the TCM. So, technically, the ECM is indeed controlling the engine, but the TCM is telling the ECM, in this case, "Too much torque - back off!!"



Rusty

 

[AH64ID]

Using typical controller logic, the interplay between the modules might go something like this: the transmission control module (TCM) would tell the ECM that a slip condition exists. The ECM would then proceed to reduce torque until the slip condition is no longer reported by the TCM. So, technically, the ECM is indeed controlling the engine, but the TCM is telling the ECM, in this case, "Too much torque - back off!!"



Rusty

Correct. The TCM is just letting the ECM know what's going on, but the TCM does not change the fueling, the ECM controls fueling based on the feedback its getting from all of its sensors, some are connected directly to the ECM and some thru the TCM.

 

[RVTRKN]

Just had a conversation with a trany tech that knows the programing, I got laughed at when I asked about TM, in a nut shell, it does think, in fact it has adaptive memory that can change the shift patterns to the individual. It even knows how much fluid it takes to fill the clutch packs when they start to wear, to engage the clutches as that changes. As he and his co-worker put it "hell their smarter than we are". :-laf As for the G56, we are the TM controls.

 

[RVTRKN]

I have only driven a few dmaxs, but they run like raped apes when you go to pass. . crazy acceleration.

Not the 05 service truck at 10K GVW I had to drive. I even had it checked for problems for poor acceleration when passing as well as the poor MPG, I was told normal.

 

[Mikey-KE7LBB]

I even had it checked for problems for poor acceleration when passing as well as the poor MPG, I was told normal.

Standard response!! Just like all of the Ford owners complaining of a knock or tick that shows up around 3000 miles and that is the same line of BS they get :-laf

 

[Powder Extreme]

Standard response!! Just like all of the Ford owners complaining of a knock or tick that shows up around 3000 miles and that is the same line of BS they get :-laf

Just like the guy who's transmission wont downshift at full throttle... LOL



Many dealers out there will use the old "working as intended" routine and ignore the problem. GM, Dodge, Ford... even Mercedes has told me that, they were just a whole lot nicer about it.



Arguing about whether or not the Allison defuels the motor or sends a signal that the ECM reads and then defuels the motor is merely symantics. The end result is the same, the fuel to the engine is reduced as a result of potential transmission damage being detected.



When the spurs connected to the boots worn by the cowboy contact the horse in the withers he goes faster. But was it the spurs or the cowboy that caused it to happen?

 

[NIsaacs]

The way gearing works it all works out okay. Honestly even 460 ft/lbs that the 03 SO's had was limited and you couldn't really tell unless you got a tuner that decreased the limiting, but 800 ft/lbs un-limited thru gearing would be very difficult to drive on the street. Ask some of the guys running aggressive tq management reduction, their wives won't drive the truck, too much power off idle.



IF you could obtain full fueling/power in each gear this is how much tq would be to the rear wheels assuming a locked converter (which we know won't occur in the lower gears, so the tq would be higher). 4. 10 gears were used.



1st 10,594 ft/lbs

2nd 6,035 ft/lbs

3rd 4,624 ft/lbs

4th 3,280 ft/lbs

5th 2,689 ft/lbs

6th 2,066 ft/lbs



As you can see you can limt it quite a bit and not really effect power to the wheels in the sence were its a "limiting" factor.



The 800 ft/lbs of tq is needed and available when your doing 45ish+ mph, where wind, weight, and incline takes it's biggest toll.

Nice torque table comparison, thanks. Yes, I had to be real careful when I would launch a real heavy load off highway in soft ground. I think the Dana 80 is rated 10,000 ft/lbs intermittent and 2500 ft/lbs continuous, I am not sure on the AAM. Now add 2. 7 gear reduction for low range in the transfer case



Nick