Voltage Problems and Your Explorer's Automatic Transmission

Contributed by Eric N.

I own one of the first Ford Explorer XLT's off the assembly line so many of the recall related problems I experienced first hand with no factory support. Through it all I still love the explorer no matter how quirky it gets. At about 80,000 miles my Explorer started slipping in and out of overdrive. The expense of a new transmission install was unappealing, so I put it off as long as possible. Turned out it was just long enough for the alternator to wear out, and upon replacing the alternator the voltage regulator was replaced. The Explorer uses an alternator with a built in voltage regulator, so replace one you replace both. Now I suppose you wonder why all the discussion about alternators & regulators when the transmission was the real subject. The overdrive for the explorer is electronic - any drop in voltage through the electronics cause the system to change gears. This is not the cure all for all slipping overdrives, but I know of four other Ford Explorer owners who gave up their cars because Ford service rebuilt, replaced, and re-replaced their transmissions without finding the cause but charging them the whole way. Test your Voltage regulator first. This sometimes can be difficult to trace because of variables of operating temperature and intermittent failures may hide the problem, but its a lot cheaper than any tranny work.

Contributed by Steve C.

I have a '91 4wd eddy bauer and I too was faced with replacing the automatic tranny after experiencing problems with the overdrive not engaging and disengaging properly, also the shift points seems off. After seeking justice from two tranny shops and two ford dealers I thought I was going to be stuck with replacing it. About the same time I started having intermittent starting problems, sometimes you would turn the key and it would be dead but everything else worked. I got lucky - while tracing down the starting problem I fixed both. There was a wiring harness on the drivers side front of the engine compartment, it came loose and was touching the exhaust manifold causing a couple of wires to ground out, like the voltage regulator a grounded wire will cause the same problems. I never did have the tranny fixed and it runs good as new now with about 120k miles on it.


Contributed by Jeff M.

My son's wife has a 91 EB that was driving my son nuts-the trans began "hunting" between drive and, and the torque converter was locking up prematurely. He spent $150 at a (good) transmission shop, who told him the transmission was fine, but something electronic was at fault. Recommended he take it to Ford to get it "plugged in" for analysis. He did so, in spite of his lack of respect for dealers, and was rewarded accordingly. They kept the car for 6(!)days-and pronounced it to need a transmission, and charged him $240 for analysis in spite of their inability to repair it. He (my son) had already "unplugged" the trans ECU and found the trans to function nearly normally when unplugged. So he went on the net, saw your site, lifted the hood, and immediately found a harness laying on the left exhaust manifold-and about four wires fried together. He separated the wires and taped them. VIOLA!!! Drives like a dream. He does intend to lay a little "knowledge" on the dealership, and intends to let the trans shop know as well-so they might better serve their next customer/s. You also mentioned in the "removing the instrument cluster" that fuse 26 has to do with the OD, and one of your contributors had found a shorted wire by the shifter/column joint. Fuse 26 may very control one of those fried wires-may not be a bad idea to mention that under the "voltage loss..." heading in the transmission arena.




Updated March 26, 2001

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