Today’s Transmisssion and Fluid Service

As automotive technology continues evolve, the automatic transmission has undergone many changes and continues to adapt to the ever-changing automotive market. Years ago the first transmissions were 2 speed units and worked amazingly well. Today they have evolved into electronically controlled 8, 9 and 10 speed units with paddle shifters. The main reasons for the increased number of speeds and complexity is all about fuel economy and emissions. Without getting too technical, most engines have a rpm range and torque curve that is more efficient than at other operating ranges. Keeping the engine operating in these optimum ranges is achieved by using the transmission to do so. The shifting of these units are controlled by engine and transmission computers that receive several inputs from various sensors and switches, make decisions and calculate shifting strategies that are outputted to pulse width modulated solenoids and switches to control gear selection. Wheeeeew, That was a long sentence!

As a driver of all this technology, what do I need to know? Unless there is a noticeable change in shift quality, sluggishness, slipping or an illuminated “check engine or transmission light” basic fluid maintenance and fluid level checks are all that’s needed. Following your owners manual is always a good place to start along with recommendations from a knowledgeable full service repair facility. Some manufacturers recommend servicing as low as every 12,000 miles to some that say it should not need to be serviced for the life of the transmission. This is where the experience from a knowledgeable technician can help. Often after automobiles are made there are running changes to there maintenance and service that won’t be updated in the owners manual. Using the correct or updated fluids when servicing a transmission is extremely important as shift quality and transmission life can be affected. Transmission fluid is very high in detergent that helps keep shift valves clean and free moving. There are many different qualities in friction modifiers added that aid in shift feel and quality. Some of these manufacturer grade fluids are over $20 a quart and may require as many as 5 -15 quarts of fluid depending on the make and model. So, having a transmission serviced with a universal fluid may save you money in the short term but, what are the long term costs. Many transmission replacements range from $2500-$5500 or higher

The biggest enemy of a transmission is heat. Overheating the transmission by towing or load above the recommended limits for the vehicle. Just because a vehicle is able to tow or haul something doesn’t mean it should. I have seen some cars overloaded beyond belief leaving home improvement stores, not just trucks. Overheating affects internal seals and o-rings that uses the fluid pressure to compress servo pistons and clutch packs. If those seals begin to leak they will not clamp those components with the force to properly engage them. Over time those clutches and bands will begin to slip and may fail causing a big repair bill. Many times the slippage from these worn or overheated seals will be noticed more when the transmission is still cold and seal better after the transmission warms up some. When transmission fluid begins to turn brown or worse black, it is a sign of the clutch or band material mixing in the fluid. Some transmissions are somewhat known to do this and regular maintenance will help keep them going.  Others may indicate a more serious problem. If the fluid is extremely dark or black, fluid flushing may make it worse or cause a failure after fluid servicing. The thick or heavy fluid is allowing seals to work or seal. Flushing with new transmission fluid that is high in detergent may cause the internal seals to leak and the transmission to slip or not engage at all.

Like many other services, it’s always more cost effective to maintain it than to repair it. We can help you with all your transmission service or repair needs. Hope this was helpful in explaining some of the areas of transmission operation and service.

Thanks for your business!

Kevin Hough, Pres.  ASE Certified Master Technician and L1 Service Specialist