The transmission seems to be harder to shift when warm. Is this normal?
Normally shifting would become smoother as the transmission warms. Some questions:
1. When starting from a stop does the clutch engage when the pedal is a few inches off the floor, or when it is real close to the floor? If the pedal is close to the floor you could have a hydraulic problem, a broken pressure plate, or varying thickness of the clutch disc. If the pedal is operating normally, but it is hard to select a gear, you may have a problem with the transmission pilot shaft trying to seize in the pilot bushing.
2. Are there any accompanying noises? vibrations?
3. Is it easy to a select a gear to get the truck moving, then hard to select gears while moving down the road?
4. Does this happen all of the time? only when pulling heavy loads?
Other possibilities are: oil has degraded and is no longer lubing properly, oil level is low, wrong type of oil, and synchronizers / blocking rings worn.
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- John