Hard, and sometimes impossible shifting into first and reverse is caused by the clutch disc not moving away from the spinning flywheel. This is commonly referred to as the "clutch is not releasing". The number one cause is the hydraulic system that operates the clutch is leaking and has low fluid.
Transmission Fluid Low or Poor Condition – Vehicles low on transmission fluid or that are operating with worn out or contaminated fluid are likely to experience hard shift conditions. Lack of adequate lubrication within the transmission can cause several problems, including hard shifting.
This can occur for a few different reasons. It can be anything from an internal pressure issue, a sensor problem, or a transmission failure. Most of the time it is caused by a sensor issue. I have seen a lot of throttle position sensors and air flow sensors cause this if they are not reading right.
It could be due to worn-out friction material or a pressure plate defect (or combination of both). It could also be caused by an oil leak contaminating the clutch plate. If there is a fault with the clutch, you will need to find out whether it's a mechanical issue or whether the clutch facing has been contaminated.
Among the possibilities are faults in the throttle position sensor, mass airflow sensor, vacuum leaks, a clogged fuel filter, defective EGR valve or control circuit, and worn out spark plugs and wires.
Within the engine at that point, an over-rev condition will occur and internal-engine components will momentarily spin far faster than what they were originally designed to do. The valve spring keeps the engine's valves seated, opening and closing following the camshaft lobe.
One main reason why the automatic transmission in your car may not be shifting smoothly is the ECM is going bad. It is best to get this checked out by an experienced auto mechanic technician who understands the electrical system. Other indicators include bad connections within, or worn out sensors and faulty solenoids.
This happens because, if the master cylinder and/or release cylinder is damaged or leaks, it can cause loss of pressure on the fluid, this can make the clutch not disengage properly. If the clutch and engine do not disengage properly, the manual transmission will be hard to shift all gears, or fail to shift entirely.
Automatic transmissions that shift hard, jerk or shake during a shift change may mean your transmission fluid needs changed or fluid level is low. In manual transmission vehicles, abnormal gear shifts could indicate damaged gear synchros, worn clutches or other, more severe issues.
Second gear is usually the first of the gears to start to fail because it is the most used gear of the set. The hub and clutch, baulk ring, and gear cone wear and cause the difficult engagement. The gearbox requires an overhaul to remedy the problem.
If your transmission is slipping, be aware of the signs.
Engine revs or chugs. Slow, weak or delayed acceleration. Difficulty shifting gears or hard shifting. Grinding, whining or other strange noises.
When changing gear, take your foot off the accelerator and press down on the clutch completely before switching to another gear. Changing the gear correctly will ensure that your car stays healthy. Listening to the engine while driving will enable you to understand the car when it needs a gear change.
Remember each car will be geared slightly differently, but a good rule of thumb for changing gears is that first gear is for speeds up to 10 mph, second gear is for speeds up to 15 mph, third gear is for speeds up to 35 mph, fourth gear is for speeds up to 55 mph, fifth gear is for speeds up to 65 mph, and sixth gear ...
Can I go from 5th to 2nd/1st? Yes it is recommended that in a modern manual transmission you can skip gears when going up or down.
The proper way to slow down your manual transmission-equipped car is to downshift. When you take your right foot off the brake, you press the clutch with your left foot, shift down a gear.
Fixing Rough Transmissions
All you have to do is add a bottle of Transmission Treatment & Leak Stopper. It's specially designed to smooth rough shifting. As you might guess from the “leak stopper” part, Tranny Honey stops transmission leaks, so low fluid levels should no longer be a problem.
Despite this, we wouldn't recommend regular downshifts into first due to the strain it can put on the components within the transmission. So next time you feel that first gear is necessary to launch out of a corner, make sure you think about the required pedal inputs to perform a smooth shift.
Typically, when your transmission begins to fail you may start to notice some form of difficulty when changing gears. Occasionally you may hear or feel a clunk noise when you shift gear. Another sign of a rough shifting is difficulty in accelerating to the speed for the gear that it is in.
Dirty Air Filters
The air filter functions to prevent dirt and debris in the air from entering the engine. If it's dirty, it could restrict airflow to the engine, thus reducing the amount of oxygen that the engine gets. This causes an uneven oxygen-to-fuel ratio in the engine which leads to misfiring and car jerking.
If you drive manual, most manufacturers will recommend changing your transmission fluid every 30,000 to 60,000 miles. If you have automatic, you can typically boost that range up to 60,000 to 100,000 miles. There's no harm in changing your fluid early.