Transmission Tuning & TCM Unlock (T93) 10L1000
Before reading further - the TCM you send into HP Tuners MUST be from the vehicle - no core or TCM swaps will work.
Tuning and Relearn Instructions
The factory TCM tuning from GM in the T93 leaves a lot to be desired when it comes to proper shift control and torque converter lockup (TCC –L/U). The programming, combined with a weak 7/8/9/10 clutch pack and overdrive drum arrangement leave this transmission vulnerable during loaded scerios and when power had been increased. Factory 10 speed trucks under full throttle from a stop shift in the order of 2/3/4/5th - TCC lockup/6th TCC lockup/7th TCC lockup/8th TCC lockup/9th TCC lockup/10th TCC lockup. This shift pattern arrangement makes for an uncomfortable pattern and shift control that users coming from a 6 speed Allisons do not perfer.
Additionally towing in the mountains or at grade GM has conventionally used a poor TCC and downshift scheduling. We find many users including ourselves have needed to place the truck in manual mode to be able to control engine breaking speeds and make the ride more enjoyable when loads are approaching max GVWR.
Furthermore the factory 10 speed operates with partial EEMC (partial lockup) of the TCC clutch nearly all the time. This is used by GM to make on and off throttle transitions more comfortable. We have found, after testing that we will be removing most of this partial EECM anytime the truck is under load to keep TCC slip down and efficiency up. There are no downsides to this. In fact most of the Transmission failures we have seen have been from torque converter failure.
TCM tuning should be paired with the same tune file writer as the ECM tuner. In similar fashion to the way GM would have done this the ECM and TCM work together, its important for the tune file on the TCM side to have similar torque model inputs as the ECM side. This is even more prevalant on the 10 speed allisons.
Technical Breakdown of what we are providing.
--> First, we are removing most of the partial EEMC for torque converter lockup as described above for effeciency reasons and reliablity of the TCC.
--> Second, In TOW/HAUL we are improving the downshift times under load, to maximize exhaust breaking efficiency, and holding the transition into 9/10 out longer to preven the TCM from shift hunting. Once the transmission gets into 10th gear we will be commanding more time vs. torque to allow the motor to load against the gear to minimize un-necessary downshifting (think going over small overpasses with a trailer on).
--> Third, We will be raising line pressure in the areas needed (high load low RPM) and leveraging the torque based shift control to raise line pressure as the commanded torque model increases. The eliminates over pressurizing the valve body and only commanding the line pressure that is actually required. TCM Tuning on modern controllers is much more than just "raising line pressure"
--> Fourth, we are reducing the shift timing (transient shift time) during gear changes 1-7. This will keep the truck from siting over 3200RPM while waiting for the next gear change to occur. This is critical for keeping the engine in its power band during full throttle operation
What the user will see as a result of TCM tuning
- Increased transmission line pressure for holding more HP and torque
- Improved shift timing
- Re-designed torque converter lock-up strategy
- Allows power transfer from the engine to the wheels more directly
- Allows transmission to handle the larger earler torque curve that can be delivered by the L5P
What is required?
- Modified T93 TCM (unlocked)
- HP Tuners MPVI/RTD Device
- 4 - HP Universal Credits
!!This calibration package can only be installed using the HP Tuners MVPI3 / 4 or our Private label RTD devices (RTD 4) !! As such the end user MUST have either an unlocked TCM from HP tuners or from VSE directly and also MUST either purchase licensing credits and MVPI3 /4 or RTD4 or already have them in their possession.
