P0784: 4-5 shift malfunction: the transmission did not make the shift between gears 4 and 5 as the computer commanded

4-5 shift malfunction

Severity: Severity not verified — if the car runs badly, have it inspected

The sources define the code and list causes but do not say whether you can keep driving.

P0784 in short

P0784 means the transmission computer saw a problem with the 4-5 shift: the gear it got did not match the gear it asked for. TroubleCodes.net lists low or wrong fluid, blocked passages, wiring, shift solenoids and internal wear. A scan tool and a fluid check are the first steps.

The computer compares the gear it commands with the ratio it measures. If the 4-5 shift does not produce the expected ratio, it sets P0784. The Delaware DMV code list titles it 4-5 shift malfunction.

TroubleCodes.net lists fluid problems first, then blocked internal passages, wiring and connectors, shift solenoids and internal mechanical failure, with a control module fault rare.

Most likely causes

These are general causes for this code across vehicles. None is specific to one make or model.

Cause 1: Low, degraded or wrong transmission fluid
Common general cause
Why it ranks here
TroubleCodes.net lists low or degraded fluid and the wrong fluid type first.
What would change this
Rises if the fluid is low, dark, burnt-smelling or the wrong type. Falls if the fluid is correct and clean.
Cause 2: Damaged wiring or corroded connectors
Common general cause
Why it ranks here
TroubleCodes.net lists damaged wiring and corroded connectors.
What would change this
Rises if the harness is chafed or a connector is corroded. Falls if the circuits test good.
Cause 3: Faulty shift solenoid
Common general cause
Why it ranks here
TroubleCodes.net lists defective shift solenoids and has them tested with a scan tool.
What would change this
Rises if a solenoid fails a command or resistance test. Falls if all solenoids respond correctly.
Cause 4: Clogged internal passages
Common general cause
Why it ranks here
TroubleCodes.net lists clogged fluid passages and has the pan removed to look for debris.
What would change this
Rises if the pan holds debris or the fluid is dirty. Falls if the pan is clean.
Cause 5: Internal transmission mechanical failure
Common general cause
Why it ranks here
TroubleCodes.net lists mechanical failures and says metal in the pan points to one.
What would change this
Rises if metal is found in the pan or pressure is low. Falls if a fluid or solenoid fix restores normal shifts.
Cause 6: Transmission or engine control module fault
Possible — needs testing
Why it ranks here
TroubleCodes.net says a module defect is rare and to suspect it only after everything else is ruled out.
What would change this
Rises only after fluid, wiring, solenoids and pressure all check out.
How to test the transmission control module (tcm)

What to test first

Start at step 1. Each result tells you what it means and where to go next.

Step 1: Read all codes and freeze-frame data from the engine and transmission modules with a scan tool before clearing anything.
Low riskTool: scan tool that reads the transmission module
- IfOther shift, pressure or solenoid codes are stored
  It meansDiagnose them as one fault.
  Go to step 2
- IfP0784 is alone
  It meansCheck the fluid first.
  Go to step 2
Step 2: Check the fluid level, colour and smell by the maker's method.
Use caution
Warning:Many transmissions are sealed and the level depends on fluid temperature. Do not open a fill plug without the maker's procedure; fluid can be hot.
- IfLow, dark, burnt or the wrong type
  It meansFluid is the first suspect.
  Points to: Low, degraded or wrong transmission fluid
- IfFluid looks normal
  It meansInspect the wiring.
  Go to step 3
Step 3: Inspect the transmission wiring for continuity, ground and resistance problems, and the connectors for corrosion.
Low risk
- IfDamage or corrosion is found
  It meansRepair it and retest.
  Points to: Damaged wiring or corroded connectors
- IfWiring is sound
  It meansHave the solenoids tested.
  Go to step 4
Step 4: Have a shop test shift solenoid function with a bidirectional scan tool, and look in the pan for debris.
Best left to a shopTool: bidirectional scan tool
Warning:Dropping the pan releases hot fluid and the vehicle must be safely supported. A sealed transmission may need the maker's procedure; leave it to a shop.
- IfA solenoid fails
  It meansSolenoid fault.
  Points to: Faulty shift solenoid
- IfDebris or metal is in the pan
  It meansInternal wear or blocked passages.
  Points to: Internal transmission mechanical failure
- IfSolenoids pass and the pan is clean
  It meansCheck line pressure and the control module.
  Points to: Transmission or engine control module fault

Symptoms

Check engine light
Harsh, erratic or unpredictable shifting
Slipping or a gear that will not engage Gets more serious: stop and have it checked.
Limp mode, transmission overheating or higher fuel use Gets more serious: stop and have it checked.

How to fix

Step 1: Do not clear the code before the transmission module has been read.
Step 2: Have the fluid level and condition checked by the maker's method before any part is replaced.

Parts and cost context

Transmission control module (TCM):A control module fault is rare per TroubleCodes.net; confirm fluid, wiring and solenoids first.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Ford

2007 · Expedition
Supported by vehicle data
Ford bulletin 0755 covers 6R75 transmission 2-3 and/or 4-5 shift flare, with the wrench lamp possibly on with P0782 and/or P0784. Whether it is still current is not verified.

0755Status unverified
Ford bulletin: 6R75 transmission 2-3 and/or 4-5 shift flare, wrench lamp with P0782 and/or P0784
2007expedition · NHTSA 10021458
Ford bulletin 0755 for the 2007 Expedition. The summary says the 6R75 transmission may show 2-3 and/or 4-5 shift flare, with the wrench lamp possibly on with P0782 and/or P0784. Only the NHTSA summary was read, not the full bulletin; the summary does not give the repair.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

All Transmission codes

P0784 questions

What does P0784 mean?

The computer found the 4-5 shift did not produce the gear ratio it commanded.

Can I drive with P0784?

We found no source that says. Slipping or harsh shifts can signal damage, so have it read and inspected promptly.

Sources and review

On-Board Diagnostic Trouble Codes (generic code title list) — Delaware Division of Motor Vehicles
P0784 trouble code page — TroubleCodes.net
0755: Ford bulletin: 6R75 transmission 2-3 and/or 4-5 shift flare, wrench lamp with P0782 and/or P0784 — Ford

Last reviewed: October 16, 2026
Written by: Saurabh K.
Editorial review: Pending
Technician review: Technician review pending

This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error

Severity: Severity not verified — if the car runs badly, have it inspected

Most likely causes

Cause 1: Low, degraded or wrong transmission fluid

Cause 2: Damaged wiring or corroded connectors

Cause 3: Faulty shift solenoid

Cause 4: Clogged internal passages

Cause 5: Internal transmission mechanical failure

Cause 6: Transmission or engine control module fault

What to test first

Step 1: Read all codes and freeze-frame data from the engine and transmission modules with a scan tool before clearing anything.

Step 2: Check the fluid level, colour and smell by the maker's method.

Step 3: Inspect the transmission wiring for continuity, ground and resistance problems, and the connectors for corrosion.

Step 4: Have a shop test shift solenoid function with a bidirectional scan tool, and look in the pan for debris.