General tech info on the 4L60E and 700R4
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General tech info on the 4L60E and 700R4
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GENERAL TECH INFORMATION: 4L60/65E AND 700R4
1-SHIFT KITS and shift points. Though shift kits do improve shifts and reduce slip, this has no affect on when the transmission shifts. In the 700R4 this is a function of governor pressure versus TV pressure. It is somewhat adjustable with the TV cable setting. On the 4L60e, however, it is strictly a PCM programming function. Though you may be able to hold gears down by using the shifter, you cannot cause the up shift to occur before the PCM commands it. In the 4L60e the up shifts are completely at the mercy of the PCM. The 4L60e can only do what it’s told, it has no mind of its own.
The 4L60e is dependent on many things to determine shift timing. They are listed below in descending order:
A-Vehicle speed and engine rpm. I list these together because there is an interdependency between them
B-Throttle position. Determines shift firmness and greatly affects kick down and part throttle up shifts.
C-Mass air flow or speed density. Though this does not greatly affect shift timing normally, it does affect shift firmness and can cause erratic shift if faulty or incorrect. Also note that in some cases with large cams and issue with the MAF may cause quick shifts from 1-2-3-4 at WOT and require adjustment of the MAF tables in the tune. Basically a MAF sensor is a piece of resistive wire. A current is passed through it as air travels across this wire it is cooled when a conductor is cooled resistance decreases and current can increase and when warmer resistance is increased and current is decreased. This current is what the PCM reads to determine how much air is entering the engine. This is then compared to set parameters in the PCM program as a determining factor for everything from fuel to air ratio to estimated engine torque output. This in turn affects trans line pressure and in extreme cases can have and affect on shift timing (CAMS,INTAKE,HEADS) can affect to this level. Other things that can affect it is a dirty air filter, Over oiled air filter in the case of the latter the oil can actually coat the resistive wire and insulate it causing the air passing over the wire to be unable to cool the wire lowering its resistance and increasing current. When this happens several things can be misinterpreted by the PCM Because the wire is warmer and the current lower the PCM may lower line pressure or, make the car run lean since basically the PCM thinks the car is taking in less air than it actually is making the PCM assume less torque or power output from the engine and to some level may even cause this to be true by leaning out the mixture significantly. Now in the case of the head and cam package etc you can get a reverse affect your taking in more air than the PCM determines based on the current passing through the MAF since the PCM is programmed that a given current equals a certain amount of air based on the original engine specs and the RPM the engine is turning along with throttle opening, When you change the ability of the engine to take in air the programs used to compare these variables become inaccurate and can again adversely affect engine and transmission operation. Its very important to make sure when doing engine mods that the person doing the tuning alterations or if doing them your self you understand all of these things well. Since not only can this hurt the performance of your car. It can also in extreme cases cause damage to your trans and even your engine. Tuning is not as simple as trans and engine they are heavily intertwined.
2-Converter lockup.Lockup is controlled by the PCM. Full throttle lockup is not possible or preferred with factory tuning, but can be accomplished with PCM tuning. However, it may smoke the converter clutch prematurely.
3-Manual shifting of transmission. Contrary to popular thought, doing this occasionally will not hurt your unit. In fact, there are some instances where it can be beneficial. For example, when roll racing, bringing on the low clutch by manually putting the transmission into first helps support the low and input sprags. Another example would be burn outs, as again it will help to support the sprags by turning on the low clutch and the overrun clutch. Placing the transmission in D3 rather than the OD position is always a good idea when using nitrous or turbo/supercharger applications. Although we use the strongest sprag available, the BorgWarner dual cage input sprag it is still the weakest link in the transmission. Also, the overrun clutch being on to help support it is a good idea. Note however that on our level three unit (which is capable of downshifting to manual first at any speed) there is a risk of over revving the engine and causing damage to the engine.
4-Transmission temperature. Transmission temperature is something you hear discussed quite often. However it is not as critical as some would have you believe. Short of boiling the fluid there are seldom short term issues. You can tell if the fluid is boiling because it would generally spray out the vent tube on top of the transmission. High transmission temperatures will cause damage over a long period of time through the hardening of seals and breakdown of fluid into varnish. It will not kill your transmission overnight but over a longer period it can. As long as you keep the transmission temperature under 230 degrees (normally lower is better of course) and under 250 intermittently you should be fine. After several stalls in a row, the temperature will rise for a short period of time. Note: The temperature reading on your gauge will vary according to the location of the sending unit can have a major affect on the temps you see. The pan is the best location to get this reading from. But it’s always true that a cooler is excellent insurance.
5-PWM (Pulse Width Modulation). What is it and how does it affect my car? PWM is the controlled slip of your converter, which basically allows the converter clutch to partially lock at lower speeds to improve fuel economy. However, this generates heat and puts wear on the converter clutch. While this is not a big problem with an OEM sized converter, it is a problem with the smaller 8-9-10 inch converters because they do not have enough clutch surface area, and they can’t absorb the extra heat generated. Nor do they have the friction area for the slip to be properly controlled by the PCM. PWM should be eliminated in any high performance application (and really any application). This function is the source of the code 1870. This function is eliminated on all our transmissions.
6-RPM AND ITS EFFECT ON TRANS LIFE, RPM as with any part of the drive train does take its toll however a properly built trans should be able to tach through 7000 with no issue. This is not true about a stock or stock rebuilt transmission. There are issues which may occur when the trans is not properly prepared. Low HI RPM pressure and undesired 3-4 clutch apply when the car is not in 3rd gear burning the clutch. MAX rpm for a stock 4L60E/65 should be no more than 6000 rpm for any extended period. Built units can do much more.
7-Vacume modulation in the 4l60e and 4l80e: Using vacuum modulation in these trans was created by TRANSGO to control line presure in and other than electronic means. While we do not incorporate this into all our units and believe the PCS is ultimately the better system. Not saying others ways aren’t fine to there are many HI HP cars running the vac mod too. There are certain instances where this mod may be beneficial. Instances of this would be when setting up the trans with a full manual valve body with no electronics for applications with no ECM. Another use though debatable would be in the case of chronic pressure control issues. Though this would be curing the symptom and not the cause as a last resort when all other avenues have failed it can and will solve the issue. You must however bear in mind that the issue causing the PCM to command the wrong line pressure may also be affecting your performance in other areas and everything possible should be done to find the cause. We do however prefer to stay with the PCS system since it can better meter line to many variables and make the vehicle much more adaptive to various situations.
8-Presure control do’s and don’ts (This is covered in another sticky pretty well)
Again this is information copied from our website and has been edited to not come across as and advertisement just some good information.
__________________
GENERAL TECH INFORMATION: 4L60/65E AND 700R4
1-SHIFT KITS and shift points. Though shift kits do improve shifts and reduce slip, this has no affect on when the transmission shifts. In the 700R4 this is a function of governor pressure versus TV pressure. It is somewhat adjustable with the TV cable setting. On the 4L60e, however, it is strictly a PCM programming function. Though you may be able to hold gears down by using the shifter, you cannot cause the up shift to occur before the PCM commands it. In the 4L60e the up shifts are completely at the mercy of the PCM. The 4L60e can only do what it’s told, it has no mind of its own.
The 4L60e is dependent on many things to determine shift timing. They are listed below in descending order:
A-Vehicle speed and engine rpm. I list these together because there is an interdependency between them
B-Throttle position. Determines shift firmness and greatly affects kick down and part throttle up shifts.
C-Mass air flow or speed density. Though this does not greatly affect shift timing normally, it does affect shift firmness and can cause erratic shift if faulty or incorrect. Also note that in some cases with large cams and issue with the MAF may cause quick shifts from 1-2-3-4 at WOT and require adjustment of the MAF tables in the tune. Basically a MAF sensor is a piece of resistive wire. A current is passed through it as air travels across this wire it is cooled when a conductor is cooled resistance decreases and current can increase and when warmer resistance is increased and current is decreased. This current is what the PCM reads to determine how much air is entering the engine. This is then compared to set parameters in the PCM program as a determining factor for everything from fuel to air ratio to estimated engine torque output. This in turn affects trans line pressure and in extreme cases can have and affect on shift timing (CAMS,INTAKE,HEADS) can affect to this level. Other things that can affect it is a dirty air filter, Over oiled air filter in the case of the latter the oil can actually coat the resistive wire and insulate it causing the air passing over the wire to be unable to cool the wire lowering its resistance and increasing current. When this happens several things can be misinterpreted by the PCM Because the wire is warmer and the current lower the PCM may lower line pressure or, make the car run lean since basically the PCM thinks the car is taking in less air than it actually is making the PCM assume less torque or power output from the engine and to some level may even cause this to be true by leaning out the mixture significantly. Now in the case of the head and cam package etc you can get a reverse affect your taking in more air than the PCM determines based on the current passing through the MAF since the PCM is programmed that a given current equals a certain amount of air based on the original engine specs and the RPM the engine is turning along with throttle opening, When you change the ability of the engine to take in air the programs used to compare these variables become inaccurate and can again adversely affect engine and transmission operation. Its very important to make sure when doing engine mods that the person doing the tuning alterations or if doing them your self you understand all of these things well. Since not only can this hurt the performance of your car. It can also in extreme cases cause damage to your trans and even your engine. Tuning is not as simple as trans and engine they are heavily intertwined.
2-Converter lockup.Lockup is controlled by the PCM. Full throttle lockup is not possible or preferred with factory tuning, but can be accomplished with PCM tuning. However, it may smoke the converter clutch prematurely.
3-Manual shifting of transmission. Contrary to popular thought, doing this occasionally will not hurt your unit. In fact, there are some instances where it can be beneficial. For example, when roll racing, bringing on the low clutch by manually putting the transmission into first helps support the low and input sprags. Another example would be burn outs, as again it will help to support the sprags by turning on the low clutch and the overrun clutch. Placing the transmission in D3 rather than the OD position is always a good idea when using nitrous or turbo/supercharger applications. Although we use the strongest sprag available, the BorgWarner dual cage input sprag it is still the weakest link in the transmission. Also, the overrun clutch being on to help support it is a good idea. Note however that on our level three unit (which is capable of downshifting to manual first at any speed) there is a risk of over revving the engine and causing damage to the engine.
4-Transmission temperature. Transmission temperature is something you hear discussed quite often. However it is not as critical as some would have you believe. Short of boiling the fluid there are seldom short term issues. You can tell if the fluid is boiling because it would generally spray out the vent tube on top of the transmission. High transmission temperatures will cause damage over a long period of time through the hardening of seals and breakdown of fluid into varnish. It will not kill your transmission overnight but over a longer period it can. As long as you keep the transmission temperature under 230 degrees (normally lower is better of course) and under 250 intermittently you should be fine. After several stalls in a row, the temperature will rise for a short period of time. Note: The temperature reading on your gauge will vary according to the location of the sending unit can have a major affect on the temps you see. The pan is the best location to get this reading from. But it’s always true that a cooler is excellent insurance.
5-PWM (Pulse Width Modulation). What is it and how does it affect my car? PWM is the controlled slip of your converter, which basically allows the converter clutch to partially lock at lower speeds to improve fuel economy. However, this generates heat and puts wear on the converter clutch. While this is not a big problem with an OEM sized converter, it is a problem with the smaller 8-9-10 inch converters because they do not have enough clutch surface area, and they can’t absorb the extra heat generated. Nor do they have the friction area for the slip to be properly controlled by the PCM. PWM should be eliminated in any high performance application (and really any application). This function is the source of the code 1870. This function is eliminated on all our transmissions.
6-RPM AND ITS EFFECT ON TRANS LIFE, RPM as with any part of the drive train does take its toll however a properly built trans should be able to tach through 7000 with no issue. This is not true about a stock or stock rebuilt transmission. There are issues which may occur when the trans is not properly prepared. Low HI RPM pressure and undesired 3-4 clutch apply when the car is not in 3rd gear burning the clutch. MAX rpm for a stock 4L60E/65 should be no more than 6000 rpm for any extended period. Built units can do much more.
7-Vacume modulation in the 4l60e and 4l80e: Using vacuum modulation in these trans was created by TRANSGO to control line presure in and other than electronic means. While we do not incorporate this into all our units and believe the PCS is ultimately the better system. Not saying others ways aren’t fine to there are many HI HP cars running the vac mod too. There are certain instances where this mod may be beneficial. Instances of this would be when setting up the trans with a full manual valve body with no electronics for applications with no ECM. Another use though debatable would be in the case of chronic pressure control issues. Though this would be curing the symptom and not the cause as a last resort when all other avenues have failed it can and will solve the issue. You must however bear in mind that the issue causing the PCM to command the wrong line pressure may also be affecting your performance in other areas and everything possible should be done to find the cause. We do however prefer to stay with the PCS system since it can better meter line to many variables and make the vehicle much more adaptive to various situations.
8-Presure control do’s and don’ts (This is covered in another sticky pretty well)
Again this is information copied from our website and has been edited to not come across as and advertisement just some good information.
__________________
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