Transmission Slipping

What's happening

Most likely causes

1. 1

   Low transmission fluid

   The number one cause. Low fluid can't hold clutch packs engaged.

2. 2

   Burnt or degraded fluid

   Fluid that smells burnt has lost its friction properties.

3. 3

   Worn clutch packs

   High-mileage wear; fluid checks fine but it still slips.

4. 4

   Failing shift solenoids

   Electrical faults that mimic mechanical slipping.

How to diagnose it — in order

1. 1

   Check transmission fluid level and condition: bright red is good, brown or burnt-smelling is bad.

2. 2

   Look under the car for red fluid leaks.

3. 3

   Scan for transmission codes; solenoid faults set codes that point right at them.

4. 4

   Note when it slips: only when hot suggests fluid breakdown; all the time suggests worn clutches.