Transmission Troubleshooting

Automatic Transmission Problems

• First thing to do, no matter the issue, is to check the automatic transmission fluid

The transmission is slipping: odds are the fluid level is low and topping the fluid level off will take care of the immediate issue(you'll still want to find out what happened to the missing fluid.

The transmission fluid is Dark and smells burnt: At this point if the transmission is shifting OK, a fluid and filter change is in order. If the transmission is causing you an issue and the level is full but still burnt looking you are looking at needing a rebuild. The dark color comes from the worn clutches inside the transmission. The clutch material is similar to that of brake pads and when they wear the leave dust similar to brake dust collecting on your wheels.

Transmission Application Guide
Transmission Temp Gauge
Transmission Temperature

Transmission Servicing and Electronic Diagnosis Manual

Transmission shifts erratically

1. Check and if not within the recommended range, add or remove transmission fluid to obtain the correct fluid level. Always use the recommended fluid type when adding transmission fluid.
2. Check the fluid level condition. If the fluid has become contaminated, fatigued from excessive heat or exhibits a burning odor, change the transmission fluid and filter using the recommended type and amount of fluid. A fluid which exhibits a burning odor indicates that the transmission has been slipping internally and may require future repairs.
3. Check for an improperly installed transmission filter, or missing filter gasket, and repair as necessary.
4. Check for loose or leaking gaskets, pressure lines and fittings, and repair or replace as necessary.
5. Check for loose or disconnected shift and throttle linkages or vacuum hoses, and repair as necessary.

Transmission will not engage

1. Check the shift linkage for looseness, wear and proper adjustment, and repair as necessary.
2. Check for a loss of transmission fluid and top off as needed with the recommended fluid.
3. If the transmission does not engage with the shift linkage correctly installed and the proper fluid level, internal damage has likely occurred, requiring transmission removal and disassembly.

Transmission will not down shift during heavy acceleration

1. . On computer controlled transmissions, check for failed sensors or control units and repair or replace defective components.
2. On vehicles with kick-down linkages or vacuum servos, check for proper linkage adjustment or leaking vacuum hoses or servo units.

   NOTE: Many automatic transmissions use an electronic control module, electrical sensors and solenoids to control transmission shifting. When troubleshooting a vehicle with this type of system, be sure the electrical connectors are fully connected, clean and not physically damaged. If necessary, clean the electrical contacts using electrical contact cleaner. The use of cleaning agents not specifically designed for electrical contacts could leave a film or damage the insulation of the wiring.

Transmission won't shift, No reverse, Stuck in Gear, No Overdrive:

These transmission problems can be caused by severe internal damage, a failed shift solenoid, failed sensor or a transmission computer module failure. Sometimes a simple software update is all that's needed to cure the shifting issues, fortunately the the check engine light comes on when there is an issue giving you a P0700 code that tells the technician that there is a transmission code present. At this point the technician can scan the transmission codes that will help diagnose the issue.

No Reverse or No Overdrive:

In most cases a solenoid has failed and needs to be replaced. The solenoids can be accessed by removing the transmission pan and filter. Usually a couple of bolts and one electrical plug and you can remove the solenoid...and no, there won't be a bunch of springs jumping out at you.

Internal Transmission Damage:

In most cases when the transmission pan is removed there will be quite a bit of small metal fragments apparent in the bottom of the pan and trapped to the magnet stuck tot the bottom of the pan. You are in for a rebuild and some hard parts.

Transmission Pan Removed

Mitchell1, also called eAutoRepair, is one of the best sources for Online automotive repair manuals. You will receive access to thousands of pages of comprehensive technical information, transmission break down diagrams, complete wiring schematics, drive belt routing, diagnostic trouble codes and much more.
Purchase Now and Access all the available information Now!

Top Categories

Serpentine Belt Routing Diagrams
Ask a Mechanic
Free Insurance Quotes
Car Owners Manuals
Auto Wiring Diagrams
Auto Repair Manuals
Auto Repair Estimates
Hybrid Cars
Nut & Bolt Measuring Charts
Mechanic's lien Form