Torque management. Myth, mystery or fact.

[Mathes308]

So, after TONS of posts, still not 100% clear on the torque management and what goes on.

Boiled down this is my take.

Stock:
Trans has the engine reduce fuel between shifts based on various inputs such as speed, throttle position etc. Saves the transmission from plowing through shifts, great idea, love it.

ECM keeps the throttle from reacting with driver input during takeoff, so even if you mash the throttle it rolls the trottle for you to keep from jarring the trans with high torque, told this may also be tied with AAM wanting 440 or so ft-lb or less on the rear until x speed is reached. This sucks for starting heavy loads but saves drivetrain.

Questions that go unanswered are.
When and how much power is shaved off, do I get 100% in second gear, third? Some have said only during torque converter lockup would you get 100% power.
What's the point in having all that power if you only get it during lockup, and how with an auto, I mash the trottle and it shifts, boom, not locked up? Doesn't make sense.
Others have stated it gives you 100% after 55 mph, I see some boxes say they fool the truck into thinking it's always doing over 55.
Well I don't drive over 60, so I guess it will be a fun 5mph gain.

So what's the real deal with torque management?
No guessing, too many guesses.

Goal is a greater understanding of what's going on and better use of my Smarty-JR
The truck runs SO SO much better with the TM low or off that I'm tempted to risk the trans.
I'm on the 70hp towing with full timing advance and factory TM
Maybe if I better understood what the TM really did I could better control my foot to save the trans instead of just letting the gushy factory TM do it.

Thoughts?

 

[cerberusiam]

TQ Management is nothing but fuel management, cutting duration and pressure at the appropriate time to limited the TQ rise generated by a shift point. TQ rise is the problem with a stock auto trans. When changing gear ratios there is a lot of energy involved in accelerating the weight of the vehicle from one gear to the next, if some management is not there the trans would just puke it guts onto the road at the first chance it got. The stock rating of engine exceeds the rating of the trans by enough it has to be managed or failure will happen sooner rather than later.

There is no way you can manually run the throttle adequately to emulate TQ management and still provide the seamless gear transitions an auto trans provides, all you can do is limit the rate of application to minimize the problems. Moving off stock TQ management will hammer 2 areas severely and a 3rd badly. The front band and direct clutch pack will take the abuse in normal driving failing rather quickly with a stock transmission build, the OD shift will be less severe but still hard on stock configuration as that is a BIG jump to OD and the TQ rise is massive without management, the only saving point is it happens far enough into the acceleration curve the impacts are somewhat minimized.

Basically the TQ management is controlled more by rpm and load than anything else, it just translates to mph because that is where the curves flatten and meet.

If you want to use the available TQ you need, at a minimum, a shift kit and several small pieces in the trans to defeat the inherent NVH. Next step is a billet cover TC and billet input shaft. A solid stock build with good gaskets and clutches plus the previous mentioned parts will allow a constant 400-450 tune and the ability to move loads pretty well. The limit at that point is going to be turbo and air requirements.

 

[Ozymandias]

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[Mathes308]

So does it allow full power after the shift is completed or does it hold back until a certain input shaft rpm is reached?

While we're on transmission topics.
What's the deal with the lockup in 3rd crap.
Every once in a while, while accelerating, shortly after shifting into 3rd it will lick the converter, then when ready to shift to 4th it will unlock right before the shift, shift to 4th and if at or over 50mph will lock the converter.
I wish it would lock the converter after the 3rd shift all the time.
Instead of wasting fuel into converter heat it grunts down and moves the truck forward.
These converters are too loose, hate it. Like driving around a manual with your foot resting on the clutch.
And I rarely go past half throttle, 2500-3250 isn't a broad band to work with.

 

[cerberusiam]

The ECU defuels when the TCM indicates a shift point then it rolls the fuel back up to the level indicated by load, speed, and throttle position.

The 03-04 trucks just had crappy shift algorithms due to lack of room in the TCM to make it work, no TH either. Light on the throttle and low load they would lock in 3rd otherwise until you got to 50 mph or so they were in fluid coupling. They all unlock on shift points, TQ rise is too high to shift locked to locked. Those trucks really benefitted from a low stall high TQ multiplication TC. They all work a lot better but the lack of control does get overridden with a good tight TC. Less throttle and more speed means lower load calculation so they lock up more often and harder.

 

[Mathes308]

Local trans shop will install a TC for $600, thinking of finding a good low stall and decent clutch pack one and having them install it.
Torn between that and a FASS fuel system, trans is cheap compared to the engine.

 

[Doubleclutch]

Ever consider a manual transmission? It sounds like you're going to spend a lot of $$$ to turn your auto into one, functionally. Then your right foot would be the TM.

 

[Mathes308]

I would love it to be manual, is the conversion hard?
I dislike autos, they have their pros but for me the cons outweigh it.

 

[Ozymandias]

Dont go with a cheap converter, you'll burn the Money. Choose a reliable Brand and you get what you pay for.
I'm perfectly happy with my BD Converter, it's a big difference to the mushy OEM Converter.

If you are not happy with the Auto for what every and want a stick shift then sell the truck and buy a stick shift - conversion will be more expensive and what I read in this forum it is difficult because of the electronics.

 

[Mathes308]

I Agee, I've already bought name brand torque converters, money well spent.
Torn on a good single or triple clutch though. The maxed out smarty jr is probably all I will ever need and I want long life so no sense pushing things.

I think a good tow build on the 48re would do me well, the prime goal with this truck is to tow. Camper, dump trailer, car trailers. My trucks spend 80% of their miles towing.
Tried to find a manual truck, good luck, slim picking. The ones I could find were out of my budget at the time.
The big question right now is, wait until this one tosses its cookies or rebuild as soon as possible (funds pending)?

Or 3rd, spend the cash and do the low stall converter and then wait for the eventual fail?

 

[cerberusiam]

No reason to consider a manual, the auto done correctly with a few tweaks will run circles around the manuals.

Unless you are towing hard and heavy all day every day all you need is a high quality single disk. Generally speaking, spend the extra $$ on a single and you get a much better TC than the same $$ on a triple.

A good single disk, a shift kit, and the few upgraded parts internally is good for 450-500 all day long. Simply can't run these engines any harder with spending a LOT more on other things.

 

[Mathes308]

That sounds like where I want to be.
When I talked to the trans shop about doing the converter I asked if they would put a shift kit in if I brought it.
They said they wouldn't do it on my trans because of the miles on it.
I've never put one in a higher mileage trans since my old TH400 in my camaro.
Should I wait for the build or put one in now to help prolong things?

I'm familiar with transgo kits, what's everyone running?

 

[cerberusiam]

If the trans health is good no problem adding a shift kit. Most places won't for warranty reasons unless they rebuild. The TransGo works well if you like it, a Superior Shift correction kit works well also and is much simpler.

 

[Mathes308]

I'm listening,
What's a superior shift correction kit?

The trans works like new, since I don't know it's history it could be new, could also be 2 miles from toast
Either way I want a firmer shift, it's comfy now but I know that's not healthy.

 

[cerberusiam]

http://www.cascadetransmissionparts.com/48reshiftcorrectionkit0304.aspx

 

[Mathes308]

Any other parts worth tossing in while under there?
Think im gonna do a parts round up Monday, need to get the amsoil in there.

 

[cerberusiam]

Billet accumulator, billet front servo cover, billet band strut and anchor.

 

[Mathes308]

Cool, shopping list.
Was wondering if the accumulator was a waste of money or not, I'm taking that being billet avoids distortion and cracking?

 

[cerberusiam]

The stock accumulator is plastic, they leak and distort bad enough with stock pressures. Crank up the pressures and they are useless, plus they age and get brittle with heat and time. The billet accumulator also have Teflon seals plus the 0-ring to seal correctly. The billet front servo cover has an o-ring seal on the servo shaft which is wear they wear and leak.

 

[Freebore]

The stock accumulator is plastic, they leak and distort bad enough with stock pressures. Crank up the pressures and they are useless, plus they age and get brittle with heat and time. The billet accumulator also have Teflon seals plus the 0-ring to seal correctly. The billet front servo cover has an o-ring seal on the servo shaft which is wear they wear and leak.

When it comes to shift kits and replacement parts for items like accumulators and input shafts, where does Sonnax fit in (Sure Cure kits)? I used to use Gil Younger's shift kits in older GM transmissions (700R4) and it helped but see a lot of information lately on Sonnax. Just curious where they fit in as there seems to be many choices now.