Quote:
Originally Posted by lasstss
Anyone on here know of a trans shop that can do a shift kit or stall converter for the 5L transmission. I have not found anyone yet.
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best bet is talk to a bmw shop, as they have been running this trans since 2000
rant time:
why is it people are in such a hurry to throw bad parts at a good trans for a cuase they don't understand? this trans was designed from the beginning to be electronicly controlled and shifted. shift timing, shift point, line pressures are all controlled by the PCM. everyhting a shift kit on an old hydralicly shifted transmission is controlled in software now. want a firmer shift? decrease amperage to your pressure control solenoid during the desired shift. more line pressure, quicker accumalator fill, faster piston apply, firmer shift. with the exception of the 4t40e, 4t80e, 5lXXe, 6lXXe and the 6tXXe transmission, every current hydramatic transmission can be traced back to an earlier design that relied entirely on hydralic controls for shift timing, shift control and shift feel. governor? try vehicle speed sensor data. TV cable? try throttle position sensor data. Vacuum Modulator? Engine Load Data. Kickdown switch/cable? again throttle position sensor.
some of the capabilities provided by computer control (edited from GM's bulletin #02-07-30-002A):
Quote:
The Hydra-Matic 5L40E/50E automatic transmissions have some unique operating characteristics with which customers may not be familiar. They have been designed to provide more of a manual transmission feel than other Hydra-Matic automatic transmissions.
Normal Mode Operation
During normal mode operation, drivers may notice increased powertrain braking after releasing the accelerator pedal. The vehicle will not coast freely when the accelerator pedal is released but will start to gradually slow down as if the brakes were lightly applied. This feels very similar to releasing the accelerator pedal on a vehicle equipped with a manual transmission.
Sport Mode Operation
Typically, Sport mode delays upshifts. The Sport mode simulates the performance driving of a manual transmission. Under certain conditions, the vehicle will maintain specific gears longer than a traditional automatic would. When driving in Normal mode in 5th gear, depressing the Sport button causes an immediate 5-4 downshift, which will be maintained for ten seconds. In any other gear, no downshift takes place when Sport is engaged. In Sport mode, the vehicle has firmer shifting and increased performance, and the transmission may remain in a gear longer than it would in Normal mode.
Driver Shift Control (DSC)
The driver manually overrides the automatic gear selection. Various mechanization options for input device and degree of override are allowed.
Performance Algorithm Shifting (PAS)
PAS overrides normal automatic gear selection during closed throttle high lateral acceleration maneuver. Lower gear is accompanied by near synchronous engine speed control for quick response upon re-opening throttle (enable threshold bias in Sport mode).
Performance Algorithm Liftfoot (PAL)
PAL prevents liftfoot upshifts while maintaining engine braking during repeated aggressive cornering.
Winter Mode
The vehicle launches in 2nd or 3rd gear instead of 1st, to avoid wheel spin in snow or ice, if selected by the driver.
Shift Stabilization
Shift stabilization is used to minimize shift business, or hunting between ranges. Based on several inputs and a map of engine torque at various RPM and throttle position, the TCM determines before making an upshift whether the engine will be able to maintain vehicle speed in the next higher range. If it calculates that it cannot maintain speed, it will prevent the upshift from occurring.
Downgrade Detection Brake Assist
Shift to lower gear with braking on downgrade based on fuzzy logic rules calculated from a thermal brake model, terrain detection, desired acceleration, vehicle speed, and mass detection.
Adapts
Adapts continually compares actual shift times to desired shift times. The transmission controls make hydraulic adjustments to assure the actual shift times approach the ideal shift time the next time the shift is made for similar operating conditions of vehicle RPM, engine load, and road load conditions. The adaptive shift process continues for the life of the vehicle to provide consistent and optimized shifts.
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