A vehicle that is shifting hard can be very unpleasant to drive. Irrespective of whether it is an automatic or a manual, a transmission that is not shifting correctly can cause serious problems out on the road and under the hood.
A vehicle that refuses to shift or go into gear easily is trying to tell you something is wrong and in most cases the culprit is the clutch or transmission. Transmissions are very complicated and have many moving components, ignoring a hard to shift issue can quickly spiral into a very expensive transmission repair.
How this system functions:
Automatic transmissions use a planetary system of gears that sends power using different gear ratios. A planetary gear set has a central gear, known as the sun gear, an outer ring that has internal gear teeth which is known as the ring gear and two or three other gears which are called planet gears and allow the gear ratio to change as the car accelerates.
The vehicle drive train is coupled to a torque converter that behaves like a clutch between the transmission and drive train. The transmission changes gears as the car accelerates or slows downs.
In a manual transmission, a flywheel is linked to the engine crankshaft and spins with it. A clutch disk is found between the pressure plate and the flywheel, which is held against the flywheel because of pressure from the pressure plate. When the clutch is engaged the flywheel spins the clutch plate and the transmission, moving the vehicle. When the clutch is depressed, the pressure plate stops applying pressure to the clutch disk letting the gear to be changed without damaging the transmission.
Most modern vehicle with a manual transmission have 5 or 6 gears.
Common reasons for this to happen:
- Transmission Fluid Leak:Transmissions are a sealed system so leaking fluid shows a serious problem. Leaks can happen in the pan gasket as well as other areas of the transmission. Transmission fluid is bright red or brown, as it gets older. If there is fluid under the vehicle it should be inspected immediately. Transmission fluid is essential for the proper operation of the transmission and low fluid levels because a leak can cause the transmission to basically self-destruct, which will result in a very costly repair.
- Failing Transmission Solenoids:Transmission Solenoids moderates the flow of transmission fluid around the transmission. Trouble shifting is a common indicator that the solenoids are failing.
- Dirty or Contaminated Transmission Fluid:Transmission fluid gets dirty and contaminated over time and must be changed. Difficulty in shifting can show that it is time to change the fluid. Transmission fluid should be flushed and changed roughly every 100,000 miles.
- Failing Transmission:Over time, especially as a car goes over the 100,000 mile mark, parts and gears inside the transmission simply wear out. This process can be dramatically accelerated if the vehicle is driven with low levels of transmission fluid. The transmission will have to be rebuilt or changed which is a very expensive repair. Signs of a failing transmission include hard shifting, humming, clunking or grinding.
- Bad Shifter Cable:Some cars use a cable to link the shifter handle to the transmission. Typically an automatic transmission will have one cable while a manual transmission will have two. Over time the cable can stretch or break. A stretched cable can make the car hard to shift into gear and the indictor needle may not line up with the gear the vehicle is actually in.
- Worn Out Clutch:Over time a clutch will wear out. The lifespan of a clutch can vary depending on the how the car is driven. Symptoms of a failing clutch not only include hard shifting but also a spongy feel to the clutch and a possible burning smell.
How important is this Fix?
Transmission repairs can start from a simple and inexpensive adjustment to a major rebuild that can be very costly. A vehicle that is hard to shift is signaling that something is malfunctioning in the transmission or clutch and ignoring the signs will most likely lead to further damage, which can dramatically increase the cost of the repair.