Our 1998 Grand Voyager 3.3 has been fairly dependable, and finally needed a rebuilt transmission last year.  After the repair it was driven on a 350-mile round trip and became stuck in successively lower gears, then spontaneously was symptom-free for months, until recently. 

This time the trip was just around town, so getting it home was easier.  When this has occurred it generally requires either driving it in second gear at 50-55 mph, or nursing it home in first gear, in which you approach high rpms at low speeds, it may more easily overheat, and driving in low gear is audible for some distance, so one receives much unwanted attention.  I took it to get a transmission flush, because once before this procedure had resolved a similar problem when the original transmission was apparently stressed by engine overheating.  The fluid was dirty then; this time I found that the level and quality of fluid was good, so flushing was unnecessary.

The place at which I was going to have the flush done asked me about the transmission, since there are nearly 170K miles on the van.  I let them know it had been rebuilt, and they said they could have done it cheaper than the $1900 I paid; they could do it for $1500.  Right away I thought “scam”, but then the manager said to check with the place that did the work, then with his company if it weren’t resolved. 

I have temporarily (lasting from less than a day to several weeks) solved this problem by unhooking the negative battery cable for five (5) minutes and then reattaching it.  This clears the TCM, namely, the transmission control module, and allows the vehicle to drive smoothly in all gears once again.

I had already checked with the place that did the transmission rebuild,  and now knew that the fluid was clean.  The symptoms reminded me of what used to happen when a part called the modulator valve went out.  TCM’s have taken their place.  The “check engine” light had been showing,  so even though this ‘98 Grand Voyager was now over ten years old, it still could be checked with a scan tool.  Computers have been on vehicles for more than a couple of decades.  I thought it over and decided to “bite the bullet” and purchase a scan tool.  I bought an Actron.  I found two codes; one, P1776, the other P440.

The P1776 code translates to “solenoid switch latched in L-R (low-reverse) position.”   The P440 code indicates an evaporative emissions, or EVAP, problem.  This can also cause the engine to run roughly, another factor in shifting gears smoothly.  I believe that several factors may help cause this “hiccup” in the TCM; spark plug wires that need replacing, and/or EVAP (evaporative emissions) problems, because they make the engine less efficient and cause it to run roughly, and finally perhaps ABS problems, because on several occasions when this problem occured I noticed the ABS light came on and the brakes spontaneously “shuddering”, or quickly and repetitively being applied and released, which would stop or subside to a degree when the brakes were applied.  I had  experienced brake caliper problems just prior to the TCM problem and this also seemed to help trigger not only the TCM hiccup but the ABS problem as well.  All interesting facts (to me), but I was glad to find that unhooking the negative battery cable for a few minutes cleared up the gear-shifting problem each time.  Much cheaper and much less trouble than buying/installing a new solenoid, solenoid switch or Transmission Control Module.