Manual transmissions suffer from wear mainly in the synchronizers. The synchronizers make shifting easier and help to prevent gear clash. Over time the synchronizers, led driver circuit which are made of brass, can wear out causing hard shifting and grinding. \u00b7Automatic transmissions can also wear out, causing slipping and uneven shifting patterns. Universal joints can wear and cause vibrations while driving. Many newer universal joints are sealed and cannot be lubricated, leaving replacement as the only option. Preventive Maintenance: \u00b7Change the fluid in your transmission at recommended intervals. Your owners manual will give you a time schedule in miles and or months. If you tow a boat or trailer be prepared to change the fluid even sooner. Most owners manuals will give you recommend intervals for severe use like towing or off-road use. \u00b7Do not "ride" the clutch if you have a manual transmission. Learn to release the clutch in a smooth motion without revving the engine too much. Revving the engine too much while pulling out can cause premature wear on the clutch. \u00b7If you do tow a boat or trailer, consider getting a transmission cooler for your automatic transmission. Temperatures can approach the boiling point in severe conditions. Most newer trucks come equipped with transmission coolers if sold with a towing package. \u00b7Make sure your universal joint is lubricated at oil changes if they are the type, which can be lubricated. When replacing universal joints try to find replacements with lubrication fittings so you can lubricate in the future. \u00b7If you have a front wheel drive car, avoid applying the gas to the floor while the wheels are turned at full lock. This puts stress on the universals and can cause premature failure. This can happen when stuck in the snow and trying to get out. What to discuss with your mechanic: \u00b7If you are noticing a vibration in the car while driving, make sure to describe when it happens. While accelerating? braking? maintaining speed? when turning?