After taking long trip over the Sierra Nevada's while hauling a trailer, I had to use 4WD to make it through the snow. After trying to shift back down to 2wd, I noticed I could no longer shift into overdrive and was stuck in 3rd gear. The XL-7 would stumble and the transmission would jump in and out of gear when the RPM reached about 4000.
I had to disable my OD and watch the RPMs all the way home.
When the first transmission stumble happened, I got a check engine light and when I read the code it came back as P1875, which meant a 4WD Low Switch Circuit Malfunction.
I was able to fix it by driving for a bit in 4WD Low, and shifting between gears in 4WD, then putting everything back into 2WD and now my OD is back. Seems like there is a switch that sticks if you shift out of 4WD and back into 2WD at too high a speed, I was about 50 MPH when I did on my trip. When that switch sticks, it prevents your transmission from shifting into overdrive to prevent damaging the 4WD gearbox at higher speeds.
