Ford Transfer Case Shudder

A customer arrives at your shop, driving a 2000 Ford Expedition, with an automatic 4×4 transfer case. The 4×4 switch on the dash, is a three-position switch…. “Auto — 4×4 High — 4×4 Low”. (The switch is in the “Auto 4×4” position) The customer has noticed that there is a “shudder” from the driveline, especially when turning a corner (ie: when turning into a parking stall or driveway )

What to do ?

Having the ‘GEM’ reflashed or replaced, is an option. But before doing that, you might consider a simple maintenance service procedure: Flushing / Changing the Transfer Case oil

Here’s what you do;

1…Place (select) transfer case in “Auto 4×4 Mode”

2…Raise the vehicle onto four jack-stands, ensuring that the wheels will rotate freely (Be sure that the front jack stands don’t rub on the inside of the front tires!)

3…Disconnect the Magnetic Clutch Coil electric connector at the transfer case.

4…Drain the oil from the transfer case, and install new oil into it.

5…Start and run the vehicle in gear for about ten (10) minutes.

6…Once again, drain the oil from the transfer case, and install new oil.

7…Reconnect the Magnetic Clutch Coil electric connector, and remove the vehicle from the jack stands.

8…Road test the vehicle while the selector switch is in the “Auto 4×4” mode.

The “Shuddering” should now be gone.

What was the cause of the “shuddering”?

Simply put…Dirt build-up on the clutch discs within the transfer case! By disconnecting the “Magnetic Clutch Coil ” electrical connector, which is being continuously pulsed 3-8 % by the GEM, (circuit #779…Torque on demand relay), the new oil has a chance to wash off the dirt build-up on the clutch discs. As a side point, Ford recommends changing the transfer case oil every 40,000 Kms.

Happy motoring !

Mike Duguay is an instructor for Injectronics Training Ltd. For course information and scheduling in your province, check Injectronics web site at: WWW. INJECTRONICSTRAININGLTD.COM