Gear 5 Incorrect ratio
P0735 indicates the transmission is not shifting into or maintaining 5th gear at the correct ratio. The engine control module detects that the gear ratio is incorrect, suggesting a mechanical or hydraulic problem within the transmission that prevents proper 5th gear engagement.
What You Might Notice
- Check Engine Light illuminated
- Delayed shift or inability to shift into 5th gear
- Transmission slipping or loss of power delivery
- Reduced fuel economy
- Vehicle stuck in lower gears or refusing to upshift
Most Common Causes
- 1
Low or dirty transmission fluid
Insufficient fluid level or contaminated fluid reduces hydraulic pressure needed for proper gear engagement. This is the most common cause and should be checked first.
- 2
Internal transmission mechanical failure
Worn clutch packs, bands, or gears inside the transmission prevent 5th gear from engaging or holding the correct ratio. This requires internal transmission inspection or rebuild.
- 3
Internal transmission blockage
Debris or sludge buildup blocks fluid passages needed to apply 5th gear, restricting hydraulic pressure flow to the appropriate clutches or bands.
- 4
Solenoid or valve body malfunction
A faulty shift solenoid or stuck valve in the transmission valve body prevents proper fluid direction to engage 5th gear correctly.
How to Diagnose It
- 1
Check Low or dirty transmission fluid — Insufficient fluid level or contaminated fluid reduces hydraulic pressure needed for proper gear engagement. This is the most common cause and should be checked first.
- 2
Check Internal transmission mechanical failure — Worn clutch packs, bands, or gears inside the transmission prevent 5th gear from engaging or holding the correct ratio. This requires internal transmission inspection or rebuild.
- 3
Check Internal transmission blockage — Debris or sludge buildup blocks fluid passages needed to apply 5th gear, restricting hydraulic pressure flow to the appropriate clutches or bands.
- 4
Check Solenoid or valve body malfunction — A faulty shift solenoid or stuck valve in the transmission valve body prevents proper fluid direction to engage 5th gear correctly.
How to Fix It
- 1
Check and service transmission fluid
Inspect the transmission fluid level and condition. If low, top it off with the correct fluid type. If dirty or burnt-smelling, perform a complete fluid and filter change.
- 2
Inspect transmission for leaks
Check the transmission pan, seals, and lines for leaks that may be causing low fluid levels. Repair any leaks found and reseal as needed.
- 3
Diagnose internal transmission damage
If fluid service doesn't resolve the issue, the transmission requires professional diagnostics with a scan tool to check solenoid function, then likely internal inspection via transmission removal.
- 4
Transmission rebuild or replacement
If internal damage is confirmed (worn clutches, broken bands, or damaged gears), the transmission must be professionally rebuilt or replaced to restore 5th gear function.
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