TROUBLE SHOOTING: Let's try and troubleshoot some common problems which your automatic transmission. WILL NOT SHIFT INTO GEAR, IS STUCK IN GEAR OR WILL NOT UPSHIFT WELL, SLIPPING OR JERKING SENSATION WHEN DRIVING: First, check your transmission fluid level and if it is low, refill.. If the fluid is dirty or smells burnt, have the fluid, filter and gasket replaced immediately. If you should feel metal particles in your fluid, you could have internal damage inside the transmission. See your mechanic. A milky color to the fluid could indicate radiator coolant leaking into your transmission fluid at the radiator. Again, refer to your mechanic. If your fluid is okay, check to see if your transmission linkage is snapping in and out of gear smoothly. If it is not, you could have a linkage problem and you'll need to refer to your mechanic immediately. In addition, check to see if the vacuum hose is connected and not worn. Replace the hose if worn. Fluid found inside a vacuum hose could indicate a worn vacuum shift modulator on transmissions that have one. If your transmission fluid is continually low, check for gasket leaks at the pan connection and if it is leaking, tighten up on the pan bolt. If leaking continues, have the gasket, fluid and filter replaced. Also, check for seal leaks at all other transmission connections as well as for leaking coolant lines. Have any leaking seals or lines replaced. If the fluid level is okay and is not burnt or dirty and everything else checks out, but the problem continues, refer to a transmission shop. The problem may only be a faulty vacuum shift modulator or the bands may need adjusting. But if not, the transmission may have to be rebuilt or replaced. TRANSMISSION STAYS IN LOW GEAR OR SHIFTS WITH A BANG AND/OR WHITE GRAY BILLOWY SMOKE FROM THE TAIL PIPE: Check for worn or disconnected vacuum hose. If hose is okay, the vacuum shift modulator is probably worn on transmissions that have one. The vacuum shift modulator is designed to make sure the gears shift smoothly. CAR WON'T START IN PARKING GEAR, BUT MAY IN OTHER GEARS: Have your mechanic check the neutral safety switch at the gear shift lever. Now let's take a look at problems that can go wrong with your drive train. GRINDING, GROWLING OR HOWLING NOISE UNDER THE REAR OF THE CAR IN REAR WHEEL DRIVES OR UNDER THE FRONT OF THE CAR IN FRONT WHEEL DRIVE: Check the drive shaft for loose Universal joint and if worn replace. If the Universal joints are okay, remove the filler plug at the differential to see if fluid spills out. If not, refill using the transmission pump until fluid does spill out. Bear in mind, the fluid in the differential also lubricates the rear axle. If the level is full, the differential could be worn and in need of replacement. On front wheel drives, check for leaking boots at the CB joints. Replace any leaking boots or worn CB joints within. Also, on front wheel drive automatic transmissions, check your transmission fluid level and if it is low, refill. If the fluid is dirty or smells burnt, have the fluid, filter and gasket replaced immediately. On cars with a front wheel drive manual transmission, you'll need to check the fluid level in the transaxle to see if it is low. If it is low, refill. Replace the fluid if it has not been replaced at the recommended intervals for your car. If everything is okay but the problem persists, you could still have a worn transaxle or worn CB joint inside the boot. See your mechanic. The problem could also be worn wheel bearings or worn bearings in a rear wheel drive manual transmission vehicle. CLUNKING SOUND WHEN SHIFTING TO FORWARD OR REVERSE OR A SOUND LIKE CHIRPING BIRDS UNDER THE CAR: Check the drive shaft for loose U-joint and if worn replace. Also, examine closely to see if the drive shaft or any connecting yokes are bent. Replace any bent parts immediately. On front wheel drives, check for leaking boots at the CB joint. Replacing leaking boots or any worn CB joints within. If no leaks are found but the problem persists, you may still have worn CB joints. See your mechanic. The problem could also be worn wheel bearings or over adjusted drum brakes causing the drums to work. See your mechanic for further diagnosis. LEAKING AT THE DIFFERENTIAL: This is usually a sign of a worn pinion seal. Have it replaced immediately. Leaks at the back of the differential indicate the need for a gasket replacement. WHEEL BEARING GREASE AT THE BACK OF THE FRONT OR REAR TIRES: Have the wheel bearings at that wheel repacked immediately. HEAVY THICK OIL AT THE BACK OF REAR WHEELS AR AT AXLE CONNECTIONS: This is likely an indication of a worn axle seal. Have worn seals replaced immediately. On cars with front wheel drive, you'll find not only the engine but also the transmission and differential under the hood. On these cars, the transmission and differential are combined into a single unit called the transaxle which takes the power from the engine and through a series of gear reductions sends this power directly to the front wheels via the shaft and constant velocity joints. The transmission and differential and front wheel drive vehicles operate in generally the same way as that of a rear wheel drive vehicle, except that the power from the engine is already parallel to the front wheels it must drive. On most front wheel drive cars, the engine and transaxle are mounted sideways in the engine compartment. The radiator, therefore, is more remote from the engine and is cooled by a separate fan that does not run off the engine. This electric fan is activated by a solenoid whenever the radiator or coolant becomes too hot. The water pump, however, is still located at the front of the engine on most front wheel drive vehicles. Maintenance of the transmission and drive train on a front wheel drive vehicle is generally the same as that of a rear wheel drive vehicle. On front wheel drive vehicles with automatic transmission, it involves periodically checking the fluid level as well as changing the fluid, filter and gasket at the transmission pan per the recommended intervals. The changing procedure is the same as that of a rear wheel drive vehicle. OTHER MAINTENANCE PROCEDURES: on front wheel drive transmissions involves checking for leaking coolant lines, a worn or disconnected vacuum hose as well as examining for gasket leaks at the transmission pan and fuel leaks at the transaxle connection. Replace any leaking or worn parts. Vehicles with front wheel drive manual transmissions will simply need to have the fluid changed in the transaxle per the recommended intervals for your car. The transaxle checking and changing procedures are generally the same as that of a rear wheel drive manual transmission, utilizing a fill and drain plug. See your owner's manual for the proper procedure and the amount and type of fluid for your car. Also, on front wheel drives manual transmissions, it's a good idea to periodically check for seal leaks at all transaxle connections. Replace any leaking seals. Another maintenance item for front wheel drives is to periodically check for worn boots at the CB joint. Replace any leaking boots immediately to avoid damaging your CB joints. Periodically, you will need to check and adjust accordingly, the wheel bearings at the front wheels as well as the rear wheels on some vehicles. Symptoms of transmission and differential problems in front wheel drives are generally the same as that of a rear wheel drive vehicle. If a problem occurs, follow the same procedures as that of a rear wheel drive car. However, on cars with front wheel drive manual transmissions, you'll need to check the fluid level in the transaxle instead of a transmission box to see if the fluid is low. If it is low, refill. Also, replace the fluid if it has not been replaced per the recommended intervals for your car. In addition, for all front wheel drive vehicle, replace any leaking transaxle seals or leaking or worn boots at the CB joints. If everything checks out, take it to a transmission specialist for further diagnosis.
Vehicles with four wheel drive utilize a transfer case that takes power from the transmission and sends it via the front drive shaft and differential to the front wheels thus giving the vehicle four wheel traction. Maintenance of a four wheel drive is the same as that of a two wheel drive except it also involves checking for seal leaks at the transfer case and front differential. It also involves checking for loose U-joints at the front drive shaft, checking for worn boots at the CB joints as well as examining the level of the front differential. Periodically, the fluid at the transfer case will need to be checked and changed at the recommended intervals. The checking and changing procedure is the same as that of a rear wheel drive manual transmission. If a problem occurs on your four wheel drive system, make sure the transfer case vacuum hose is connected and not worn. If the hose is worn, have it replaced. If your hose is okay, have the transfer case checked.
