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1999 Ford Expedition Malfunction - Drive Train & Driveline
Question: my ford expedition while driving in the rain lost its drive. The speedometer was still working as if the car was moving but the wheels were not engaged. now it seems to be able to switch from 4 whell drive to 2 wheel drive but it will not come out of the low range, even though it comes out of 4 wheel drive. when driving it you will be in overdrive by the time the truck is going 20 mph. can you tell me if this is a mechanical or electrical problem? I have looked at everything I can think of to no prevail. please help shed some light on this.
thanks,
Ted faulkner.
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Technican: Ted,
Sounds like you have a problem in the transfer case. The transfer case is where the power is split to all 4 wheels. You may have broken parts, or the electric shifter motor may not be working. You can replace the whole unit, or it can be opened and repaired.
Owner: Can the transfer case operate in low range only and be bad? Can the hi range be bad and not the low range? It swithces in and out of 4 wheel drive it just won't come out of the low range. It goes through all the gears even into overdrive.
let me know what you think?
Ted.
Technican: The transfer case is responsible for the 2WD and 4WD shift. It also has the high and low ranges inside it. The regular shifting you speak of is in the transmission, which transfers the power from the engine to the transfer case. If you cannot get it out of low range, the problem is in the transfer case, or in the motor that moves the shifter.
Technican: Ford has wirtten a technical service bulletin 01-14-01 recommending the replacement of the shift motor if it remains stuck in low after an uncommanded shift. (shifted by itself). The old style motors had a blue plate cover and were installed before 12/99. The new part YL1Z-7G360-AA has a grey plate cover.
Hope this helps,
Owner: This sound exactly like my problem. I have had it shift into 4 wheel drive on its own recently and the transfer case shift motor does have a blue cover. the only question I have is will anything need to be reprogrammed after the new shift motor is installed? it has 3 gems (generic electronic modules) in the 4x4 circuit and I dont know how they work, do they reset themselves or do they need to be reset with a computer?
Thank you
Ted.
Technican: I believe it will reset itself. If there are any additional procedures, it may be included with the part if you buy it from Ford.
Owner: well I replaced the transfer case switch motor and nothing is different. It will still not com out of the low range. the part that confuses me the most is it will shift from awd to 4 wheel drive but it stays in the low range. the 4x4 light will also blink if you drive it and try to shift from any range. i believe it must be the transfer case but with all the sensors and relays etc i wonder if they play into it. i am not sure if you read my first post but i was driving and lost all connection to the transfer case. the truck thought it was still moving and the speedometer was still going but the wheels were disengaged from the drive train. not very clear but if i stepped on the gas in was if the transmission was slipping but it wasn't because because the speedometer was still going. i am not looking forward to paying a dealership $100.00 hr to troubleshoot but it looks like i may have to. if it is the transfer case i will rebuild it my self but if it is a sensor i think i would let them fix it. dont know how it could be a sensor though because everything works yet it stays in low range. i have never seen anything like this in all my years working on cars, have you?
Ted.
Technican: Ted,
Inside the transmission case, there is a shifter lever. This is driven by the shift motor. This has 3 positions, low, neutral and high.
4WD is accomplished with an electic clutch which engages the front driveshaft all the time when the 4WD LO button is pushed. When the 4WD HI button is pushed, the clutch is engaged as needed when the sensors notice slippage between the front and rear wheels.
From your description, it sounds like the transfer case shifted out of high, stuck in neutral, then locked in low and has never shifted out again.
We are looking at a mechanical problem...try removing the shift motor and shifting the unit manually. If it will not shift, then you will need to open it! If it will shift, put it in high, reinstall the motor and see what happens.
If you want to check the motor operation, you can connect it outside the case and press the HI button to see if it turns. Here's How To Get Guaranteed Solutions In Minutes
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