Torque Management???

bradyb · February 27, 2002

Anybody have any ideas of how to remove or down grade the torque management system? I've heard terrible rumors about the fuel being limited to the engine in first gear? I have the 4LE85something transmission with 496 cubic inches of power.

Also, anybody know anything know about the transmission kits that change our 4 speeds to 6 speeds? No not a gear splitter but it's actually a transmission kit that changes some valve thing to make something do something differently. If anybody knows anything do you think that it would actually make the truck more efficient and faster or would it just help with towing?

Shaners · February 27, 2002

Brady B, I've heard the same thing about the 8100 torque management with the 4L85E.

I don't have the power you do, but the programming in my 6.0L will alow my tranny to lock the torque converter in "3" and in "4/OD". If you count them up then that would feel like a 6-speed. I only really notice the torque converter lock-up in 3 when I'm towing.

Beaux Duke · February 27, 2002

Correct me if I'm wrong but the 8.1 auto trans on a HD only comes with a 5 speed Allison. The 4L80 whatevers weren't durable enough.

Never heard of the gizmo to add 2 extra gears. I'd like to know more too.

CMNTMXR81 · February 27, 2002

He's got an Avalanche though. Allison's aren't available in the Av's. And for reference, it's a 4L80E.

Torque management is a program ran in the PCM that retards both spark and fuel timing curves during shifts to help eliminate hard shifting and increasing longevity on parts.

I don't want to say that there is a way around it, but as of now, unless you have a custom PCM program burned into it, I don't think there is.

Shaners, you are simply talking about "locking" your converter which can be done by "flashing" it with your right foot. It can also be done with a TechII which is how some dyno shops dyno automatic elctronically controlled GM transmissions.

Jpshostr · February 27, 2002

He's got an Avalanche though. Allison's aren't available in the Av's. And for reference, it's a 4L80E.

Are you sure about that? I thought it was the 4L85E that the Avs with the 8.1 have. I remember reading an article that was really touting them for their improvements over the 4L80E when mated to a 8.1L.

Shaners · February 27, 2002

Shaners, you are simply talking about "locking" your converter which can be done by "flashing" it with your right foot. It can also be done with a TechII which is how some dyno shops dyno automatic elctronically controlled GM transmissions.

I know that when I'm towing and going up a grade the tranny will shift into 3 (about 3200-3300 RPMS), then the converter will lock. When I crest the hill the tranny will shift into OD and then a little later it will lock again.

My tranny is definatly a 4L80E. We had a thread going a couple of months ago about 4L80E vs. 4L85E in the bigblock Avalanches. The RPO codes are different for the two trannies, but both are labeled as 4L80E. However we came to the conclusion that the tranny in the AV is a beefed up 4L80E which is also referred to as a 4L85E... (I don't really know...) The RPO codes for the 2 trannies are MN8 and MT1. My 6.0L HD has the one code and my buddy with the bigblock AV has the other...

CMNTMXR81 · February 27, 2002

GM doesn't list it on Powertrain's website and I haven't found any technical manuals pertaining to an 85E, so as far as I'm concerned, it's nothing more than a factory modified 4L80E.

The only other trans that sticks out is a 5L40E which BMW gets from Powertrain.

Your example when you are towing and the converter locks up at 3200-3300rpm's is normal. That's your stall lockup speed. Actually I think that's kinda high, but this is a truck. Most factory lock up speeds are in the 2600-2800 rpm areas.

Here is a way to show you how to lock your converter in normal driving, when you want to acclerate or to pass. You can do it when either empty or when towing.

In most circumstances, most people just floor it, wait for the trans to hunt for a gear then wait for the trans to lockup and accelerate.

Instead of doing that when you're cruising and you go to pass, quickly depress the gas pedal about 3/4's of the way, let off and then mash it to the boards again. This is what we call "flashing" or "loading" the converter. What it does, is it quickly speeds up the impeller in the torque converter to match the speed of the crankshaft. When you mash it to the floor again, now the impeller is much closer in speed to that of the crank (as in essence you've "spooled" it up), and therefore you are at a 1:1 ratio. Anotherwords, for each 1 rotation of the crankshaft, the torque converter is also turning in 1 rotation. Also known as "locked up."

This is as best as I can explain it.

Shaners · February 28, 2002

GM doesn't list it on Powertrain's website and I haven't found any technical manuals pertaining to an 85E, so as far as I'm concerned, it's nothing more than a factory modified 4L80E.

Your example when you are towing and the converter locks up at 3200-3300rpm's is normal. That's your stall lockup speed. Actually I think that's kinda high, but this is a truck. Most factory lock up speeds are in the 2600-2800 rpm areas.

I don't disagree about the 4L80/85E tranny. The original thread was what was the difference between the 2 different RPO codes, and the answer that came back most often was that one of them was a beefed up 4L80E which alot of people were reffering to as a 4L85E...

You are right about the RPM speeds. When the truck "locks up" in 3 the RPM drops to about 2800 RPM. My RPMs may be a little higher because of the 4.10 gears in my truck. Unloaded and with the torque converter locked I turn 2400 RPM @ 70 mph in OD.

CMNTMXR81 · February 28, 2002

I must've missed that thread. I'd like to read it if you can find it.

Otherwise I think your converter is doing what it's supposed to be doing. Generally factory converters are kinda "sloppy" in order for them to retain their driveability.