3-speed manual transmission will not shift into gear while truck is running and fluid is full.

There are a few possible reasons why your 2014 Fuso 515 manual transmission might not shift from neutral into gears when the engine is running but will shift when the engine is not running. The clutch is not disengaging properly: The clutch is responsible for engaging and disengaging the transmission from the engine. If the clutch is not disengaging properly, it can cause the transmission to not shift gears properly. The synchronizers are worn or damaged: The synchronizers are located in the transmission and help to match the speed of the engine and the transmission when shifting gears. If the synchronizers are worn or damaged, it can cause the transmission to not shift gears properly. The transmission fluid is low or dirty: The transmission fluid lubricates and cools the transmission. If the transmission fluid is low or dirty, it can cause the transmission to not shift gears properly. The transmission is faulty: If the transmission is faulty, it can cause the transmission to not shift gears properly. If you are experiencing this problem, it is important to have your vehicle diagnosed by a qualified mechanic to determine the root cause of the problem. Once the cause of the problem has been identified, the mechanic can recommend the necessary repairs. Here are some tips to help prevent this problem from happening in the future: Use the clutch properly: When shifting gears, use the clutch to disengage the transmission from the engine. Have your transmission serviced regularly: The transmission fluid should be changed according to the manufacturer's recommendations. Avoid shifting gears when the engine is under load: When the engine is under load, it can put stress on the transmission and cause problems.

Sounds like the transmission fluid temperature is high. Check for blockages of the fins on the oil cooler if there is an external one. The oil cooler inside the radiator won't cool properly if the coolant level is low or the radiator fans are not running at full speed.

Usually dirty transmission fluid/filter (no noises) You can try adding a full bottle of Lucas Oil Transmission Stabilizer fluid...you don't need to drain anything...(could also just be low tranny fluid) Follow the instructions, warm tranny, motor running...add full bottle...manually shift through gears...The cost is about $11. even at Walmart...Hope this helps.

P0731 Ford - Incorrect First Gear Ratio
Possible causes
- Low transmission fluid level
- Dirty transmission fluid
- Shift solenoids
- Transmission mechanical problems
- Transmission hydraulic control circuit

p0732 Gear 2 Incorrect ratio
Possible causes
- Low transmission fluid level
- Dirty transmission fluid
- Faulty Shift Solenoids
- Shift Solenoids harness is open or shorted
- Shift Solenoids circuit poot electrical connection
- Transmission mechanical problems
- Transmission hydraulic control circuit

Start by inspecting the transmission oil level and condition, and change fluid if necessary.

also check OUTPUT SHAFT SPEED OSS for proper installation and function

hope this helps

is it auto or manual ? the inner trans axle are the drive shafts , don't think they would stop engaging gears , would be best to get a mechanic as could be a number of things

Possible causes
- Low transmission fluid level
- Dirty transmission fluid
- Faulty Shift Solenoids
- Shift Solenoids harness is open or shorted
- Shift Solenoids circuit poot electrical connection
- Transmission mechanical problems
- Transmission hydraulic control circuit


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have you checked the transmission fluid in it to see if it is low?

Manually shift thru all gears up & down the scale. Try adding Motorcraft Additive Friction Modifier, available from Ford parts dept. This REALLY STINKS!!! Don't get any on you. Pour into trans fluid. Drive a few miles shifting manually thruthe gears, then do a normal start stop drive several times. This will luburcate trans, normally used for differential but has worked in automatic transmissions of all makes for years. Otherwise mechanical problem for transmission repair facility.

Check the hydraulic clutch fluid, if it is full then either the clutch is not releasing fully, the fluid inside the transmission is low, if the fluids are not low then the transmission will have to be replaced or rebuilt.

If the whine is there than the main bearing is already worn adding fluid will not save it, you will have to swap it or rebuild it. sorry i know you were hoping for something better.