9c1fanatic

I have a theory on bearing failure on these so called "maintenance free" hubs. Obviously on older vehicles where you had to pack grease at least everytime you did the brakes it kind of forced you to change them, inspect them or re-pack them and they lasted. In the police fleet, we see some cars/trucks got 100,000 miles + on the original hubs without failure. Some fail in as little as 15k. This is with many sustained high speed runs in pursuits and just routine emergency response where speeds reach triple digit speeds multiple times just in one busy shift. Now I know some designs are just faulty or at least less than desirable. I think on average the GMT800 trucks showed higher than normal rates of failure compared to other vehicles than came before and after. That being said, I'm convinced that duty cycle is a huge factor in bearing failure when there is no routine maintenance that can be performed. In the police car world, I believe it comes down mostly to how many times and or how long the vehicle has been driven in water, mud, etc deep enough to submerge the hubs (which happens all the time on police cars believe it or not) over the life of that particular set of hubs. Another factor is violent curb strikes, pot holes etc, rough roads, side loads from high speed cornering that occur during the life cycle of that particular hub or hubs. In trucks, all these same things can be variables with the addition of increased loads caused by larger wheels, tires, left kits etc. When its just one side that fails, it could be a combo of duty cycle along with an extraordinary wheel strike on a curb, pothole or other road hazard, that you either don't know about because someone else was driving the vehicle, the vehicle was purchased used, or maybe you just forgot about that huge ladder you ran over on the highway 3 years ago that is just now catching up to your bearing hub? Not too different from someone that has engine failure 5 years and 100,000 miles later because jiffy lube started the engine without oil and let it run for 2 minutes before realizing their mistake, then filling it up with oil and sending it out the door with the customer none the wiser. Engine is working fine at that moment but just lost 150,000 miles off its expected life...

I also feel for those who have experienced these (common on the forums) failures. To offer this from a severe use fleet perspective where problems are almost universally encountered well before normal retail vehicles are, I can say this, I work for a police department in Texas with over 100 police vehicles in its fleet. Various makes and models from the big 3. All of them have common failures we see across the fleet with a particular make/model. I'm not going to go into these because its not relevant to this discussion. But in regards to the issues discussed in this thread we have not really seen in our GM products. We have GMT 900 Silverado's 5.3L/4L65E and GMT 900 Tahoes with the 5.3L 6L80E combo, we have many Chevrolet Caprice 9C1s with the 6.0L/6L80E, and also have K2XX Tahoes 5.3L Ecotec/6L80E and T1 Silverados with the 5.3L/8L90E. Exactly NONE of these vehicles have had any issues with engine failure, AFM related problems, lifters etc and they range in age of 1 year old to 12 years old. Its true that as vehicles become more complex with government and consumer driven "enhancements" reliability goes down. There are hundreds of things than can fail on a new vehicle of any make or model that didn't even exist 20 years ago. The government is pushing for more fuel economy and us consumers have to have all the ridiculous technology in the vehicles and the car companies put it in so they don't fall behind the competition. This is one reason why I cant muster up the courage to depart with my 1991 Chevrolet C1500 5.7L/5 speed truck. It will outlast all of these vehicles and when something does break, the repair bill is always under $200. Hell, you can disconnect almost any sensor you want and it still runs where as a new silverado, a loose BCM ground wreaks havoc on the whole truck.