Does removing Torque Mangament Kill the Trans?
09-24-2005, 01:16 AM
#21
TECH Veteran
I have zero washers in the 1-2 accumulator. Personally, unless the 1-2 shift is fundamentally, physically different from other shifts, requiring a violent shift (for what reason I can't fathom), I don't know how/why it is set up this way. Makes no sense to me whatsoever. And it can't be good for the tranny.
Everything else is fine but the 1-2. The 2-3 is perfect at all throttle levels, 5% to 95%, with a corresponding increase in firmness (and decrease in shift time) as more throttle is applied. This is how the 1-2 should be IMO. And yet, the Transgo guy raved about my 1-2 shift as it is right now.
This reminds me of the B&M shift kit I put in my '71 Monte Carlo. It made the ride really unpleasant. I was told later that the shift kit was not very good for the tranny. It also brings to mind the "loud exhaust = high performance vehicle" way of thinking. I've got a straight through exhaust system right now, and it's quieter than stock.
Everything else is fine but the 1-2. The 2-3 is perfect at all throttle levels, 5% to 95%, with a corresponding increase in firmness (and decrease in shift time) as more throttle is applied. This is how the 1-2 should be IMO. And yet, the Transgo guy raved about my 1-2 shift as it is right now.
This reminds me of the B&M shift kit I put in my '71 Monte Carlo. It made the ride really unpleasant. I was told later that the shift kit was not very good for the tranny. It also brings to mind the "loud exhaust = high performance vehicle" way of thinking. I've got a straight through exhaust system right now, and it's quieter than stock.
09-24-2005, 01:22 AM
#22
Originally Posted by Naked AV
I have zero washers in the 1-2 accumulator. Personally, unless the 1-2 shift is fundamentally, physically different from other shifts, requiring a violent shift (for what reason I can't fathom), I don't know how/why it is set up this way. Makes no sense to me whatsoever. And it can't be good for the tranny.
Everything else is fine but the 1-2. The 2-3 is perfect at all throttle levels, 5% to 95%, with a corresponding increase in firmness (and decrease in shift time) as more throttle is applied. This is how the 1-2 should be IMO. And yet, the Transgo guy raved about my 1-2 shift as it is right now.
This reminds me of the B&M shift kit I put in my '71 Monte Carlo. It made the ride really unpleasant. I was told later that the shift kit was not very good for the tranny. It also brings to mind the "loud exhaust = high performance vehicle" way of thinking. I've got a straight through exhaust system right now, and it's quieter than stock.
Everything else is fine but the 1-2. The 2-3 is perfect at all throttle levels, 5% to 95%, with a corresponding increase in firmness (and decrease in shift time) as more throttle is applied. This is how the 1-2 should be IMO. And yet, the Transgo guy raved about my 1-2 shift as it is right now.
This reminds me of the B&M shift kit I put in my '71 Monte Carlo. It made the ride really unpleasant. I was told later that the shift kit was not very good for the tranny. It also brings to mind the "loud exhaust = high performance vehicle" way of thinking. I've got a straight through exhaust system right now, and it's quieter than stock.
If a tranny isnt really "built around the kit" then yes it can be bad. And like you said also too nasty of a shift at light throttle will snap shafts and do ugly things to the input drum. Thus why the Beast is availible. Try and change your shift time for the 1-2 shift.
09-24-2005, 10:47 AM
#23
This can be smoothed out through programming. Raise the duty cycle curve vs. throttle position toward the lower TPS values. Look specifically at first and second gear only.
The reason the 1-2 shift feels different is because it's done by a band. Bands do not have a linear response to apply pressure vs. shift time. Since they're wrapped around a spining drum then they to self-energize and the rotation pulls itself tighter. The result is a jolt if angagement is too fast for the amount of torque being handled.
The 2-3 shift is the engagement of the 3-4 clutch pack as the band releases. Clutch packs respond better to decreases in shift time because they do not self energize. Shift time decreases in proportion to apply volume and pressure.
-James
The reason the 1-2 shift feels different is because it's done by a band. Bands do not have a linear response to apply pressure vs. shift time. Since they're wrapped around a spining drum then they to self-energize and the rotation pulls itself tighter. The result is a jolt if angagement is too fast for the amount of torque being handled.
The 2-3 shift is the engagement of the 3-4 clutch pack as the band releases. Clutch packs respond better to decreases in shift time because they do not self energize. Shift time decreases in proportion to apply volume and pressure.
-James
09-24-2005, 11:01 AM
#24
Removing all tm in my truck fried my 3-4 clutch packs after about 20 miles. I have a completely built 60e with the hd-2 shift kit in there and I love all teh shifts they feel nice and firm most of the time and almost shirp the tires on the 1-2 so I feel the transgo kit does what it is advertised to do it just sounds like your tuning needs some tweaking Naked AV.
09-24-2005, 04:21 PM
#26
It doesn't matter if you have FBW or a cable throttle body, its the computer sensing too much power going through the drive train. With a stock tuned PCM it will pull timing out on either throttle body type.
Mine is an 02 and before I got a tune in the thing would just fall on its face if you hammered it from a stop, especially if your traction was an issue.
The **** almost got me t-boned by a ******* dump truck one day!!! I pulled out after waiting forever at an uncontrolled intersection, and booooogggg went the engine ,then the thing pulleed hard agin and went side ways on me!!
The whole time the truck was closing fast.
The **** scared and pissed me off at the same time.
What really sucks is torque management and GM putting the **** in there to keep drivetrain warranty claims low!!
As for the FBW it may contribute to some of the things you guys are talking about but it is not all to blame.
Mine is an 02 and before I got a tune in the thing would just fall on its face if you hammered it from a stop, especially if your traction was an issue.
The **** almost got me t-boned by a ******* dump truck one day!!! I pulled out after waiting forever at an uncontrolled intersection, and booooogggg went the engine ,then the thing pulleed hard agin and went side ways on me!!
The whole time the truck was closing fast.
The **** scared and pissed me off at the same time.
What really sucks is torque management and GM putting the **** in there to keep drivetrain warranty claims low!!
As for the FBW it may contribute to some of the things you guys are talking about but it is not all to blame.
09-25-2005, 01:42 PM
#27
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Originally Posted by TG02Z71
It doesn't matter if you have FBW or a cable throttle body, its the computer sensing too much power going through the drive train. With a stock tuned PCM it will pull timing out on either throttle body type.
Mine is an 02 and before I got a tune in the thing would just fall on its face if you hammered it from a stop, especially if your traction was an issue.
As for the FBW it may contribute to some of the things you guys are talking about but it is not all to blame.
Mine is an 02 and before I got a tune in the thing would just fall on its face if you hammered it from a stop, especially if your traction was an issue.
As for the FBW it may contribute to some of the things you guys are talking about but it is not all to blame.
with the DBW however, there are additional ETC limiters to contend with that work in conjunction with the traditional method of spark retard to control torque.
ETC TPS% Max: This is the maximum allowed ETC throttle percent based on the current percentage of torque being delivered. The PCM uses this to limit the ETC opening rate to maintain traction.
there are a tranny tables that can be manipulated to smooth the lower RPM PT shifts, such as the Base Shift Press vs Torque vs Gear and the Upshift/Downshift Pressure Modifiers that add/subtract pressure from the Base Shift Press table.
using these along with a slight increase in the 1-2 shift times for the lower torque ranges (0-160lb/ft) may help with the harsh 1-2 shifts at PT. FWIW.
09-25-2005, 04:50 PM
#29
Originally Posted by James B.
The objective of every automaker is to make their automatic transmissions provide a smooth and practically seemless shift. In a clutch pack or band engagement this can be accomplished by extending the apply time. The longer the apply time is the more heat is produced in the clutch material as those rotating surfaces are slowly brought to equalization. The wider the gear ratios are in a transmission the longer the shift will need to take to provide the desired smoothness. The 4L60/65/70-E has the widest range of any 4-speed auto on earth. At some point the amount of time the shift needs to take to be smooth exceeds what the total surface area of clutch material can provide while staying within a safe temperature range. Once that threshold is approached the only way to get the desired shift feel is to reduce the torque being transmitted though the clutches to a level the band or the clutch pack can handle. Torque management is not so much there to stress the parts less, it's there to make the friction materials last longer while still providing smooth shifting.
good thought provoking post thanks for sharing
Last edited by 02sierraz71_5.3; 09-25-2005 at 04:58 PM.
09-25-2005, 04:58 PM
#30
Ive said it once and Ill say it again the 1-2 shift can be tuned with the pressure adjusting tables-base and the 1-2 upshift dont change the values at 0 tq but change them up to about 160 or so mine are set around -10 and scaled down as calculated tq goes up. My shifts are fine and if need be all I do is back off the peddle a little on the 1-2, tune it to your liking