How do I set up 6L80E part-throttle and WOT shift tables after a gear and tire change in an engine swap?
Run the Gear/Tire Wizard in VCM Editor: enter the new tire diameter (or revs per mile) and final drive ratio, and the wizard auto-scales the T43 TCM shift tables to preserve shift RPM. Then hand-check the part-throttle upshift/downshift tables (indexed by TPS %) and the WOT Shift Speed / WOT Shift RPM tables, because at WOT the transmission will not shift until BOTH the MPH and RPM thresholds are met. Log a pull afterwards and confirm shifts happen at the commanded RPM.
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Who this applies to
- Computers: E38, E67
- Engines: 5.3L, 6.0L, 6.2L Gen IV LS V8
- Transmissions: 6L80E, 6L90E
- Not for: P01/P59 4L60E/4L80E swaps (different speedo/shift tables); 8L90/10L80 (different TCM architecture)
HP Tuners VCM Editor, 2014+ T43 TCM with separate upshift/downshift tables (Silverado/Sierra, Camaro, etc.)
- Edit > Gear/Tire Wizard: enter the new tire diameter (or revs per mile) and the new final drive ratio, then click Adjust. The wizard auto-scales the transmission shift tables. auto-scale shift tables after gear/tire change
- Write calibration only, log a WOT pull with RPM, Vehicle Speed, Trans Current Gear and TPS, and confirm each shift fires at the commanded RPM. verify by log
2007-2013 T43 TCM with combined up+down tables
- Same Gear/Tire Wizard pass, then verify TCM [15000] Main Shift Table (1-4), TCM [15050]/[15051] 5th/6th shift speeds, and TCM [15046]/[15047] WOT Shift Speed and RPM. [15000], [15050], [15051], [15046], [15047]
Careful
- Set WOT Shift RPM below the engine fuel-cutoff RPM or the engine bounces off the limiter mid-shift.
- Do not zero out trans torque management on a stock 6L80E to cure a shift-timing problem; late shifts under full torque are what break clutches.
- If the shift schedule is correct but shifts are harsh or flaring, the problem is pressure/torque management, not the shift-speed tables — get a tuner, not more MPH.
More in transmission tuning, or build a checklist for your swap with the tune checklist tool.
Go deeper
Check this first
- Log RPM, Vehicle Speed, Trans Current Gear, and TPS at WOT; compare actual shift RPM/MPH against the TCM tables.
- Check speedometer accuracy against GPS; a wrong VSS tire revs-per-mile value shifts every MPH-indexed table and causes early/weak shifts.
Try this, then this
- Re-run the Gear/Tire Wizard with measured tire diameter (not sidewall math) and the actual rear gear ratio. — A wrong wizard input scales every shift table and the speedometer wrong, producing early weak shifts and a scanner-vs-actual MPH gap. Worked if: Scanner MPH matches GPS and part-throttle shifts land at stock RPM.
- Lower the WOT Shift Speed MPH table a few MPH (keep WOT RPM where you want it) and re-log. — At WOT both thresholds must be met; if MPH is set too high for the gearing the RPM qualifier is crossed first and the shift hangs, then slams. Worked if: 1-2 and 2-3 shifts fire at commanded RPM without hitting the limiter.
Key numbers
| What | Value |
|---|---|
| Gear/Tire Wizard auto-scales transmission settings | enter tire diameter and gear ratio, wizard auto-scales |
| WOT shift requires both MPH and RPM thresholds | shift executes only after both met |
Time and cost: HP Tuners vehicle license for ECM+TCM write (one owner reported two credits covered both modules); about an hour for the wizard plus 2-3 log/test passes.
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