Transmission Service

Transmission fluid explained

The purpose of automatic transmission fluid is to lubricate, clean, cool and provide the hydraulic pressure necessary to ensure smooth operation of the vehicle's transmission. An automatic transmission creates a great deal of internal heat from friction. Under normal driving conditions, a transmission operates at 175 degrees which is the normal range most fluids are designed to operate. If the fluid temperature goes much higher, the life of the fluid begins to plummet.

The problem is even normal driving can push fluid temperatures well beyond the safe limits. At elevated operating temperatures, automatic transmission fluid oxidizes, turns from a bright red to brown. As heat destroys the fluids lubricating qualities and friction characteristics, varnish begins to form on the internal parts (such as the valves in the valve body) which interfere with the operation of the transmission. If the temperatures get above 250 degrees rubber seals begin to harden which leads to internal leaks and pressure loss. The transmission begins to slip and eventually the clutches burn out and the transmission calls it quits.

Keep it cool

Automatic transmission fluid is cooled by a small heat exchanger in the bottom tank or end tank of the radiator. Any number of things can push automatic transmission fluid temperatures beyond the system's ability to maintain safe limits: towing a trailer, mountain driving, driving at sustained high speeds in hot weather, stop-and-go driving in city traffic and rocking from forward to reverse when trying to get unstuck from mud or snow. Problems in the cooling system itself such as a clogged system, restricted air flow through the cooling fins, low coolant level, defective cooling fan, fan clutch, water pump, thermostat or radiator cap can diminish automatic transmission fluid cooling efficiency.

What to service and how

At Honest1 we start with the manufactures suggested interval, the most common being every 30,000 miles. We recommend an automatic Transmission Fluid Exchange Service with a filter being replaced every other time. Why a fluid exchange? Most automatic transmissions hold a minimum of 12 quarts of fluid. When the pan is removed and the filter changed you only get 3 to 5 quarts of fluid out, leaving 2 thirds to 3 quarters old fluid in the torque converter, lines, filter and hoses. When Honest-1 performs a Transmission Fluid Exchange Service we get all the old fluid out and replace it with new. It just makes sense. By performing a fluid exchange at regular intervals the filter can be replaced every other time.

The transmission fluid will also tell you if service is needed before the manufactures suggested interval. If the transmission fluid is starting to turn brown it is an indicator that a service should be performed. We check your transmission fluid during our famous Honest1 Comprehensive Vehicle Inspection.