Torque Management And My 4l60e

[satori]

I'm new to the GMT800 platform. Up until a week or so ago the newest Chevy I've had was a '90 1500 with a 350/5sp. (other than my wife's '98 Regal GS but that don't count)

 

The first thing I noticed with the 5.3L in my 2005 Tahoe 4x4 is that it has decent power once it's rolling but it's weak off the start. As I mentioned in another thread, it almost feels like it's surging until it reaches 20 or so MPH. Hell, even a Hyundai pulled away from me from a light. Then I found this board and I've been reading through tons of threads over the last few days and came across terms like "Torque Management" and "Abuse Management" and that you can remove this nanny feature with a tune. That sounds pretty good to me, but then I saw this thread about the sun gear stripping in the 4l60e transmission:

http://www.gm-trucks.com/forums/index.php?showtopic=83260

 

I see tons of tuning threads so I know it's pretty common to do, which is encouraging. At least I know that all the information I will need is just a few clicks away right here. (I'd be happy if this Tahoe had half as much low end torque as my '90)

 

However, I don't see any of those threads addressing the weak point in the transmission. Do you guys that tune just do it and not worry about the stress on the sun gear? Or is this problem less common than I'm percieving? Should I just do the damn tune and not worry about the sun gear?

[minibike132]

I don't think you mean the sun gear you are probably seeing posts about the reaction sun shell. A tune should not affect the shell in my experience. I don't think I've ever seen a tune affect that trans with that engine. The shell gets killed by reverse dropping, nobody thinks they do it and everyone does. More power has little effect on the shell.

[satori]

Cool, thanks for the reply. I saw that it was mostly caused by going into reverse while still moving forward, but since it's also used during 1-2 shifts and 3-4 shifts, I was worried that it would stress it if there was more power going on during those shifts.

[Jennabear]

Firmer shifts is actually better for your transmission, it is less wear on "soft" components.

[satori]

So is the whole purpose of the reaction sun shell to make smoother shifts, and the quicker the shift the less it's even active?

[Pigw33d]

I have a 2005 Chevy 1500 5.3L. I went to pull my boat out of the water and couldn't go anywhere. The tires didn't spin I had little to nothing for rpm's. Is this a result of torque management? My boat is just a small fiberglass fishing boat and should be easily pulled from the water with my truck. Any ideas would be most helpful.

[txab]

No, it's not due to TM. Have you checked for any stored codes? How does the truck drive and start other times?

[00Silverado4x4]

If your vehicle is weak off the start line, I'd say it may be time for a tune-up, tune and maybe even a regear of the diffs.

[02suburbanZ71]

Well abuse mode pulls timing off the line when it senses abuse it cuts the fuel to 1/2 the cylinders. Thats probably a contributing factor. And i noticed for best acceleration dont floor it, but punch it 3/4 of the way off the line. Try to clean the TB that helped me. Some more food for thought is ETC. I've drive. Many gmt 800's and i do tell the difference from drive by cable and wire.

[02suburbanZ71]

This should shed some more light on the matter

TQ MGT.pdf

TQ MGT.pdf

TQ MGT.pdf

TQ MGT.pdf

[kmborland]

I have a tuned truck and vette servo with a stock trans that has over 190k on it. 36k of those miles are with the tune and servo, trans is still shifting great and the fluid is bright red with no burnt smell to it. That dead spot you feel off the the line is actually a different tune called fuel enrichment. The truck doesn't seem to move till about 2800-3000rpm right. That is because you have to be at full throttle for three seconds before you get the correct amount of fuel needed at full throttle. What is happening is, you are asking the computer for full power but the computer isn't giving it to you until it reads full throttle for 3 secs. This alone cuts 20lbft of torque and about 10hp in that 3 sec period. It plays into TM but is mostly there to help fuel economy. So, from a stop light, and you want to leave the line fast, 1/2 throttle it until you pass the stall speed on the converter, then mat the throttle. truck will be much faster and will avoid the fuel enrichment tune in the computer.

 

Now, for the torque management , I do not know how much TM the tuner took out but every now and then, I can feel the TM cut in when driving. I feel it most when I turn from a side street onto a main street. Turning onto the main street slow, the guy behind me is closing fast, I hit the throttle (1/4 throttle to 1/2 throttle). Before hitting the go pedal, the trans has already asked for a shift with the 1/4 throttle calculation. Once I hit the pedal harder, the trans shifts early into second , the truck bogs down for a second, then the truck starts to go but still in 2nd gear. When it does this, I can actually feel the TM cutting in to avoid the full hit of power on the trans. most of the time with the tune, my truck will stay in 1st and run but every now and then, it will do this.

 

The guy who tune my truck says the worst thing for the trans is the 4-2 downshift. It wears the band out bc it has to unlock the band, then the clutches, then re lock the band which has to stop the sunshell to give you second. At highway speed, with 2.5 ton truck, that is a lot of stress on the trans. Another thing he said is if you truck hits the rev limiter on the 2-3 shift, that is the kiss of death for the trans. Also, a lot of people keep saying that the trans is hit or miss on life span. I know of people who baby their truck and the trans quit before 100k. Then there are people,like my dad and myself, who beat on the trans and it will last 150k+.