Does removing Torque Mangament Kill the Trans?
Sep 23, 2005 | 12:54 AM
#11
Originally Posted by James B.
You can answer this question for yourself with a little understanding of why it's programmed in there in the first place.
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.
Installing a shift kit makes shifts faster. Faster shifts mean more firm, but do not go overboard. Tightening up those shifts a little bit will prolong the life of the clutch materials, or allow you to reduce torque managment only at the expense of shift smoothness. Do not go overboard. The worst thing you can do to the geartrain in a 4L60/65/70-E is set it up to shift hard. Jolting shifts WILL kill these transmissions - hard parts WILL fail. Slightly more firm than stock is good but jolting neck-snapping tire-chirping shifts will be a quick death.
If you remove 100% of the torque management without doing any other programming or valvebody changes (shift kit) then you can expect to burn up your 3-4 clutch pack after just a few dozen WOT 2-3 shifts. It's that quick.
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.
Installing a shift kit makes shifts faster. Faster shifts mean more firm, but do not go overboard. Tightening up those shifts a little bit will prolong the life of the clutch materials, or allow you to reduce torque managment only at the expense of shift smoothness. Do not go overboard. The worst thing you can do to the geartrain in a 4L60/65/70-E is set it up to shift hard. Jolting shifts WILL kill these transmissions - hard parts WILL fail. Slightly more firm than stock is good but jolting neck-snapping tire-chirping shifts will be a quick death.
If you remove 100% of the torque management without doing any other programming or valvebody changes (shift kit) then you can expect to burn up your 3-4 clutch pack after just a few dozen WOT 2-3 shifts. It's that quick.
I understand why its in there. Its just that in many cases TM has been the trannys demise.
Sep 23, 2005 | 06:54 AM
#12
I am not looking for jolting shifts, just more direct feel with the gas pedal and throttle body. I think its the FBW that I want to get rid of. I dont think GM should have put the 700r4 in these trucks too weak.
Sep 23, 2005 | 11:29 AM
#13
TECH Fanatic
Joined: Dec 2004
Posts: 1,708
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From: Houston,Texas
Originally Posted by dug
I dont think GM should have put the 700r4 in these trucks too weak.
Sep 23, 2005 | 04:55 PM
#16
The Electronic Throttle Control (ETC) in our rides can be tweaked. A good tuner can make changes to increase the ETC opening % based on torque applied, reduce/eliminate spark retard used in both engine and tranny tables for torque management, and speed/firm up those shifts. or you can buy a tuning application like HPT, EFILive, etc... and you can twek til your heart's desire. This will make it "feel" more like a cable operated TB.
Sep 23, 2005 | 08:48 PM
#17
Originally Posted by Okie5.3
The Electronic Throttle Control (ETC) in our rides can be tweaked. A good tuner can make changes to increase the ETC opening % based on torque applied, reduce/eliminate spark retard used in both engine and tranny tables for torque management, and speed/firm up those shifts. or you can buy a tuning application like HPT, EFILive, etc... and you can twek til your heart's desire. This will make it "feel" more like a cable operated TB.
Sep 24, 2005 | 12:46 AM
#18
TECH Veteran
Joined: Mar 2004
Posts: 4,632
Likes: 2
From: Sun Diego
Originally Posted by James B.
Installing a shift kit makes shifts faster. Faster shifts mean more firm, but do not go overboard. Tightening up those shifts a little bit will prolong the life of the clutch materials, or allow you to reduce torque managment only at the expense of shift smoothness. Do not go overboard. The worst thing you can do to the geartrain in a 4L60/65/70-E is set it up to shift hard. Jolting shifts WILL kill these transmissions - hard parts WILL fail. Slightly more firm than stock is good but jolting neck-snapping tire-chirping shifts will be a quick death.
My 1-2 shift jolts. There really is no other way to describe it. I've been trying to convince myself otherwise, but in the past 2 weeks I have been starting to let off on the gas right before the 1-2 shift, just to forego experiencing that harsh, jolting, crappy 1-2 shift.
To be more specific, it is when the throttle is between 10%-50% that the 1-2 shift is the most harsh, while between 50%-80% it is nearly that harsh, but not quite so. When I am at WOT is smoothes down to a quick, firm, seamless shift, like I imagine it should be all the time.
So I have a choice - I can floor it all the time until I get through the 1-2 shift, run at 5% throttle until I get through the 1-2 shift, or try and use my own foot timing by letting off the throttle right at the 1-2 shift, which is what I've been doing lately. None of these options are acceptable to me.
To top it off, the guy at Transgo who drove my truck said the 1-2 shift was perfect! For some reason, hurling and lurching a 3-ton truck forward at 20 mph doesn't seem healthy to me.
At this point I am willing to try some programming fixes, and if that doesn't work, at minimum I'm returning my 1-2 accumulator to stock configuration with the stock spring. I have zero spacers, so I think the spring is the only Transgo part in there right now.....
Sep 24, 2005 | 12:52 AM
#19
Man I still feel a RANDOM jolt in my 1-2 shift. And I just have the metal pistons and the boost valve. The worse part is that my shifting at WOT is pretty sloppy. THe randomness of the 1-2 shifting pisses me off. I cant seem to narrow it down. Programming is the answer I think.
Sep 24, 2005 | 12:53 AM
#20
Originally Posted by Naked AV
If this is true (and I have no doubt it is, simply because it makes sense and I know James has lots of experience), then the Transgo shift kit for the 4L60E suffers from extremely poor design.
My 1-2 shift jolts. There really is no other way to describe it. I've been trying to convince myself otherwise, but in the past 2 weeks I have been starting to let off on the gas right before the 1-2 shift, just to forego experiencing that harsh, jolting, crappy 1-2 shift.
To be more specific, it is when the throttle is between 10%-50% that the 1-2 shift is the most harsh, while between 50%-80% it is nearly that harsh, but not quite so. When I am at WOT is smoothes down to a quick, firm, seamless shift, like I imagine it should be all the time.
So I have a choice - I can floor it all the time until I get through the 1-2 shift, run at 5% throttle until I get through the 1-2 shift, or try and use my own foot timing by letting off the throttle right at the 1-2 shift, which is what I've been doing lately. None of these options are acceptable to me.
To top it off, the guy at Transgo who drove my truck said the 1-2 shift was perfect! For some reason, hurling and lurching a 3-ton truck forward at 20 mph doesn't seem healthy to me.
At this point I am willing to try some programming fixes, and if that doesn't work, at minimum I'm returning my 1-2 accumulator to stock configuration with the stock spring. I have zero spacers, so I think the spring is the only Transgo part in there right now.....
My 1-2 shift jolts. There really is no other way to describe it. I've been trying to convince myself otherwise, but in the past 2 weeks I have been starting to let off on the gas right before the 1-2 shift, just to forego experiencing that harsh, jolting, crappy 1-2 shift.
To be more specific, it is when the throttle is between 10%-50% that the 1-2 shift is the most harsh, while between 50%-80% it is nearly that harsh, but not quite so. When I am at WOT is smoothes down to a quick, firm, seamless shift, like I imagine it should be all the time.
So I have a choice - I can floor it all the time until I get through the 1-2 shift, run at 5% throttle until I get through the 1-2 shift, or try and use my own foot timing by letting off the throttle right at the 1-2 shift, which is what I've been doing lately. None of these options are acceptable to me.
To top it off, the guy at Transgo who drove my truck said the 1-2 shift was perfect! For some reason, hurling and lurching a 3-ton truck forward at 20 mph doesn't seem healthy to me.
At this point I am willing to try some programming fixes, and if that doesn't work, at minimum I'm returning my 1-2 accumulator to stock configuration with the stock spring. I have zero spacers, so I think the spring is the only Transgo part in there right now.....