Hi casey8. Welcome to the forum. This is the "ever since" syndrome every mechanic dreads. It is also common with a lot of radios. "Ever since you changed my oil, my power antenna doesn't work. What you gonna do about it?" That's my favorite.
It is more likely the problem is related to loose solder connections on the cluster itself since it does work sometimes. However, being one of the most complicated computers on the vehicle, it is common for them to develop a problem in the "reset" circuit that does not show up until the battery is disconnected or run dead. That reset circuit is not a protection circuit as you would normally think of a circuit breaker. It's purpose is to set the millions of transistors in the microprocessors from some random state to their starting point so they can all talk to each other. The only time these reset circuits work is for a few milliseconds after power is restored meaning the battery is reconnected or recharged. Those circuits might not function again for years when the battery is replaced.
In your case, it is almost certain the battery was disconnected during the transmission service. The cluster, (or any other of the many computers), could have developed a problem months or years ago that would not show up until the battery was disconnected.
That's the bad news. The rest of the story is there could indeed be a problem caused indirectly by replacing the transmission. Most common would be a loose or corroded pin in an electrical connector. When moisture gets past the rubber seals, the terminals can start to corrode in all areas except where they are touching. When they are unplugged and later reconnected, their position changes a little so contact is made on a corroded spot. Intermittent operation is the result. Three days after replacing the engine in my van, two injectors stopped firing intermittently. Simply unplugging the connector and reconnecting it caused enough scratching action to produce a clean spot on the terminals. The engine has been running fine now for over 12 years. Would you call that the mechanic's FAULT or simply a result of other service? Nothing was done wrong or improperly and it ran fine for three days.
Unfortunately the easiest way to verify or disprove the problem is in the cluster itself when something is so intermittent is to replace it. There should be plenty of them in the salvage yards by now so this would be an inexpensive test. If the problem persists, look at the wiring harnesses around the engine and transmission. Besides the connector problem I mentioned, normal engine rocking can cause harnesses to slide back and forth until they wear through paint and wire insulation. Tugging on the wires or anything that causes them to change position a little can introduce an intermittent problem that was about to occur on its own very soon.
Another way to look at it, if this is a random failure, is it occurred somewhere between 0 and 120,000 miles. What were the conditions the vehicle was under when the problem first showed up? Were you driving on the highway? Was it sitting in the garage? Was the engine hot or still cold? Were you standing still at a stop light? Or did it occur while sitting on the hoist and the mechanic was on the phone ordering transmission parts? Until you know for sure what the cause is, it is extremely unfair to blame the mechanic. The people at the shop should not be so blunt as to say it is not their fault, but they've heard this so many times already including from some people who purposely try to blame a known problem on the mechanic in hopes of getting a free repair. Any reputable shop will at least inspect their work to be sure everything was done correctly but beyond that, it becomes diagnosing a different problem that you can expect to be charged for. They might also not be equipped to diagnose the new problem either. If this is a transmission specialty shop, for example, that may be all they are trained in.
If you don't feel comfortable searching for the cause of this problem yourself, and it is fairly common, have it looked at by another shop. Be sure to include the previous service history but don't be so fast to lay blame. No reputable mechanic wants to be a part cutting down his competitor, and they will assume if you do that to the previous shop, you will do it to them too. Once you find out the cause of the intermittent problem, drive it for a long enough period to be sure it is solved, THEN return to the first shop with your findings if it is related to their work. The problem with any intermittent problem is unless you can actually see the cause, you are never sure if it is fixed if it doesn't act up. You can only know if it is not fixed if it does show up again.
Sunday, July 18th, 2010 AT 11:44 AM