Transmission near Portola, San Francisco

What we service

Fluid and filter changes on the schedule that actually applies to your car (not the dealer's overpriced 30,000-mile interval). Diagnosis of slipping, hard shifts, no-shifts, fluid leaks, torque converter shudder, and check engine codes related to transmission control. Manual clutch replacement. CVT belt and chain inspection. We do not rebuild transmissions in-house; for major internal work we partner with a specialist transmission shop and supervise the job.

• Automatic transmission fluid service (drain or full exchange)
• Manual transmission fluid change
• CVT-specific fluid service (Honda HCF-2, Nissan NS-3, etc.)
• Differential and transfer case service
• Clutch replacement (manual transmissions)
• Diagnosis of slipping, hard shifts, and fluid leaks
• Torque converter and solenoid diagnosis

When to service the fluid

Most automatics benefit from a fluid service every 60,000 to 100,000 miles. CVTs typically need it sooner (30,000 to 50,000 miles for many Hondas and Nissans). If you tow, drive in heavy traffic, or live somewhere hilly (which describes most of SF), shorter intervals are smart. We will tell you what your specific transmission calls for.

Drain vs full exchange

A simple drain-and-fill replaces about 40 percent of the fluid. A full exchange replaces close to 100 percent. Full exchange is the right answer for most cases unless the fluid has been neglected for a long time, in which case we recommend a drain-and-fill first to avoid stirring up debris.

Fluids and filters we stock

Transmission fluid is one of the few places where using the wrong product can wreck a transmission in weeks. We stock Valvoline MaxLife, Idemitsu, and Mobil ATF for general automatics, plus the CVT-specific fluids (Honda HCF-2, Nissan NS-3, Toyota TC). Filters and pan gaskets are OEM or AC Delco where applicable.

When to worry

Burned-smelling fluid, metal flakes in the pan, slipping under load, delayed engagement when shifting from park, harsh shifts, or a check engine light with transmission codes are all worth a call. The earlier we look at it, the cheaper the fix.