By Paul Rupp, New Concept Auto Service

Transmission fluid does wear out.  New fluid has a pink color to it and the old fluid will appear brown and emit a slight burnt smell.  The color and smell are from the normal wear of the many clutch discs located in the heart of a transmission.

Heat is the worst thing for transmission fluid—even the relatively mild temperatures here in good old Overland Park, Kansas, can cause problems.  Elevated temperatures cause the fluid to lose its ability to withstand pressure when and where needed inside the transmission.  This is why you find additional external coolers on many trucks and SUVs.

Transmissions are mostly all built with the same fundamental concepts, and automatic transmission fluid (ATF) is manufactured by fewer petroleum companies than one would think.  ATF base stock is much the same—it is the additives that make the final difference.  With that in mind, we recommend flushing an automatic transmission every 30,000 miles for best life and performance.  Many transmission rebuilding companies recommend flushing on a frequent basis, since they constantly see the results of lack of maintenance.

The flushing procedure is like a blood transfusion.  Fluid is pumped in one end and pulled out the other with a special machine.  The fluid level is also critical and must be set at operating temperature.  Too much fluid causes it to aerate or foam up, and too little will cause slipping, leading to excess heat.  Do-it-yourselfers are finding that many newer transmissions are sealed with no dipstick, so there is no easy way to check the level or even fill it back up.

The bottom line is this: an automatic transmission will easily last more than 200,000 miles if maintained periodically.  Replacing one can cost thousands of dollars.  It is easy to do the math. You can count on us to stay on top of changes in transmissions and their maintenance requirements.

By Paul Rupp, New Concept Auto Service

I have been reading up on automatic transmission fluid (ATF) lately and changes are on the horizon.  Twenty years ago, there used to be just three types of ATF—one each for Ford, Chevy and Chrysler—and transmissions only had three speeds.  Today, transmissions have up to six speeds, and run at higher temperatures for better efficiency.  Most automatic transmissions have replaced mechanical parts with electronic solenoids, all with tighter clearances.

There are many more types of ATF to keep track of from manufacturer to manufacturer.  It can get confusing, so a shop needs accurate information.  Incorrect fluid can cause shifting problems and premature wear.  We are careful to use only OEM-supplied information to select the correct type of fluid for each particular vehicle.  We also use either synthetic blends or full synthetic ATF, which are better than mineral-based fluids.

The main difference between types of transmission fluids is in the viscosity and additives.  ATF must resist oxidation and thermal breakdown, and maintain the required viscosity levels at different temperatures.  Viscosity applies to pancake syrup– if you heat it up, it pours easier.  Transmission fluid has to resist getting too runny when hot, yet needs to flow when cold.  The nice thing about synthetic ATF is the viscosity does not change much with temperature, so your transmission works better when cold and does not thin out when hot.

Transmission fluid does wear out, and when that happens it may have a catastrophic effect on your vehicle. Check my blog next week to find out if your car, truck or SUV is at risk.

By Paul Rupp, New Concept Auto Service

Last week I had the privilege once again of working the phone bank at Channel 41’s Call for Action free helpline for car repair. I fielded 30 calls alongside eight or nine other local shop owners who donated their expertise.  This time on the phone is not a sales pitch for New Concept Auto Service or any of the local shops. We don’t even identify ourselves, but recommend a AAA-approved shop near the caller’s area.

I feel like I really helped most of the callers.  Some just wanted to talk and vent a little about a shop.  Most people were elderly and drove Buicks and Lincolns.  There was a wide array of questions.  How much would it cost to do this or that (we did not guess at pricing)?  Do I really need to flush my coolant and transmission fluid at 60,000-miles (yes)?  Several had concerns about the engine missing as they drive uphill or accelerate.  Several “crank and no start” customers wondered where they should have their vehicle towed.

One woman called in about her 66 GMC pickup she had restored.  Her throttle was sticking open, making it hard to stop.  After hearing symptoms, I advised her to have a mechanic inspect the carburetor choke.  Surprisingly, she said she just had a new carburetor installed.  Another guy with a one-ton Dodge truck described a unique situation where his park lights would stay on even when the ignition switch was off and the keys were in hand.  As I suggested several parts to inspect, he replied he had replaced them already but to no avail.  It was probably a wire shorted to power somewhere, but I would have enjoyed diagnosing this one in person!

I usually asked if they have a regular shop that they trust.  Sadly most either did very little maintenance or jumped from shop to shop.  A few folks had their favorite shop, but just wanted a second opinion. Hopefully our time on the phone helped these people out and helped make Kansas City roads a little safer this week.