Powertrain, generic · Transmission

P0756 Shift Solenoid B Performance/Stuck Off

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

A shift solenoid is an electrically switched valve in the valve body; together the solenoid states select the gear, and the module checks the result by gear ratio, slip or a pressure switch – the pattern of wrong gears shows which solenoid hangs off or on. P0756 means solenoid B is commanded on but its clutch or valve does not follow. GM's 6T70 commands second gear as a test and counts a ratio of 2.7–3.0 three times; GM's T43 2.246–2.482; GM 4-speeds recognise the pattern 4-3-3-4 and go straight to third gear with maximum pressure; Allison checks its pressure switch for 5 s – all after one trip. Ford's 'functionally failed off' covers the whole clutch circuit; an 8F35 bulletin calls for a transmission overhaul.

Likely causes

Shift spool in the valve body sticking (dirt, debris)
Internal leak or clutch fault in the circuit
Solenoid mechanically sluggish or screen clogged
Fluid level or quality wrong

Symptoms

  • Gears missing or skipped
  • Pulling away in the wrong gear, weak acceleration
  • Limp mode or gear lock-out
  • Check engine light

Repair estimate

DifficultyHardWorkshop job
Parts and labour€200–3,500
Time2–12 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

shift solenoidtransmission valve bodytransmission wiringtransmission control module

Related codes

P0757P0755P0758P0732P0733P0977

References: saabwisonline.com, gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com.