* Clutch Issues (Manual Transmission): If your Ranger has a manual transmission, a worn-out clutch, a problem with the clutch cable or hydraulics, or a damaged pressure plate are the most likely reasons you need to rev the engine to get it moving. A slipping clutch would manifest as a higher RPM than expected without a corresponding increase in vehicle speed. This is far more common than a transmission issue in a vehicle of that age.
* Torque Converter Issues (Automatic Transmission): If it's an automatic, a failing torque converter is a strong possibility. The torque converter acts as a clutch in an automatic. A worn or damaged torque converter might not be able to transfer enough torque at low RPMs.
* Low Transmission Fluid: Insufficient transmission fluid in either a manual or automatic transmission can cause various issues, including difficulty moving from a standstill.
* Other Drive-Train Problems: Problems in the driveshaft, differential, or axles could also manifest as difficulty moving the vehicle.
* Vacuum Leak (Automatic Transmission): Some automatic transmissions use vacuum assist for shifting. A significant vacuum leak could impact the ability of the transmission to engage properly.
In short: While a slipping transmission *is* a possibility, it's less likely than the other problems listed above, particularly clutch issues (if manual) or torque converter issues (if automatic). You should have a mechanic diagnose the problem to determine the exact cause. Simply revving the engine to get it moving is not a reliable indicator of transmission slippage in isolation.
