Transmission Shifting

[pexring]

I have an automatic transmission in my 1999 Explorer with 138,000 miles. When driving awhile (100+ miles), the transmission seems to kick in and out of the high gears. It starts by first kicking in and out of the overdrive for no apparent reason, so I shut-off the overdrive and all is OK for awhile. Then it starts kicking in and out of the other higher gears. For the first time the check engine light actually came on.

So the next day I took it to the Ford dealership and they drove it a good 30 miles and all worked perfect. They checked for leaks -- nothing. They checked for metal filings -- nothing. Overall they said the transmission was in great shape.

So what's happening? It doesn't happen driving around town, just out on the highway after a period of driving. Looking in the Haynes Repair Manual, they mention checking the 'transmission range sensor.' I don't know if the dealer checked this or not. If the transmission is supposively OK, could this sensor be going out? Any other ideas, my wife goes out of town in 2 weeks and I'd catch hell if she got stranded.

Thanks,
Mark

 

[pexring]

Another way I could ask the above question is, what are the signs of the 'transmission range sensor' not working properly?


Mark

 

[WillieTD]

That definitely sounds like a computer or sensor related problem. I know when I changed my TPS it cured my strange shifting problems.

 

[Runnin'OnEmpty]

Mark, since the MIL came on, there should be a code that's stored in memory. I can't believe the dealer didn't check for codes???? Checking only for leaks and metal in the pan is not being very thorough. If you can get the code(s), it will point in the direction to look.

Like Willie says, it could be as simple as a faulty TPS or VSS, or maybe a shift solenoid in the transmission valve body.