What this table does
When Haltech transmission control is holding the transmission in a gear, it aims for the line pressure in the In Gear Target table. Line pressure is what clamps the clutch packs and bands. It has to be high enough that nothing slips under full torque, but excess pressure costs pump power and makes the next shift land harder. A separate shifting target table covers pressure during the shift itself.
Where to get your starting numbers
We work down this list and stop at the first one that's available:
- A base map for your transmission. Import its target pressure tables. This is the best starting point by far.
- A tuned car with the same transmission. Copy its targets.
- The factory service manual. OEM manuals often list the pressures the transmission was designed to run.
- A base map for a different transmission. A last resort. It's better than guessing, but it can cause harsh shifts or extra wear, so treat every value with suspicion.
If the box has uprated clutches, a different pump or a modified valve body, ask the builder what line pressures they want. Their parts may need something different from stock.
Refining it
- Start high and come down. Begin on the firm side and reduce pressure until the shifts stop feeling harsh. Slip is far more damaging than a firm shift.
- Slipping in gear means more pressure. If logs show input and output speeds not matching the gear ratio while in gear, raise the target in that area.
- More torque needs more pressure. Any time you add power, revisit this table.
Log line pressure, target pressure, gear, throttle and engine load while you work, so you can see what the transmission actually got versus what you asked for.
Troubleshooting
| Symptom | Usually |
|---|---|
| Flare or slip under load in gear | In gear target too low for the torque |
| Harsh shifts everywhere | Targets too high, or the shifting table needs work |
| Actual pressure doesn't follow target | Check in gear base duty and line pressure control wiring |
For the full picture, see line pressure control and the temperature correction table.
