OBD-II code · Powertrain (generic)
P077F Reverse 2 Incorrect Ratio
Some transmissions provide a second reverse ratio (typically a slower crawler reverse for trailer manoeuvring or hill descent). The TCM detects that the input/output ratio in this gear does not match its calibrated value — slipping clutch or wrong gear actually engaged.
Is it safe to drive with P077F?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelySlipping clutch in reverse 2 element
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 3–12 h
- Emissions test
- Usually unaffected
- Parts involved
- Clutch Pack, Friction Band
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.