TheFlyingFord
Member
Howdy, so a few months ago, the front differential started grinding when I take any turns. We took it to our local mechanic friend, and he wasn't able to figure it out, and ended up removing the front drive shaft so we could at least drive it around. I decided to take on the project again after I needed the 4wd and didn't have it available.
Here's what the mechanic and I have done so far:
So we've concluded it was one of the '99 expeditions that did NOT use the vacuum actuated differential setup, since there are no solenoids, actuators, or vacuum lines anywhere around the system. It's a live-axle setup to our knowledge. The first part we replaced was the transfer case motor (Part YL1Z-7G360-A) which we purchased from our local Ford dealership. After that didn't solve the issue, we purchased a new actuator switch for the dashboard. That didn't solve the issue either. The mechanic friend replaced the relay in the dash along with the controller box (Unfortunately I don't remember the name) for the relay. (It was a small gray box with a connector on one side if that helps). I discovered a broken wire by the transfer case shift motor, which I soldered back together. This stopped the 4wd light from flashing.
As of now, the truck still isn't unlocking the front differential. I really don't want to take off that front drive shaft, either. When I switch from 4wd to AWD, you can hear the relay clicking and the slight sound of the motor turning, so it seems like everything is working correctly. I hate to think that it's an issue with the transfer case itself, but I figured I'd ask y'all for some second opinions on what could be causing the issue. Thanks!
Here's what the mechanic and I have done so far:
So we've concluded it was one of the '99 expeditions that did NOT use the vacuum actuated differential setup, since there are no solenoids, actuators, or vacuum lines anywhere around the system. It's a live-axle setup to our knowledge. The first part we replaced was the transfer case motor (Part YL1Z-7G360-A) which we purchased from our local Ford dealership. After that didn't solve the issue, we purchased a new actuator switch for the dashboard. That didn't solve the issue either. The mechanic friend replaced the relay in the dash along with the controller box (Unfortunately I don't remember the name) for the relay. (It was a small gray box with a connector on one side if that helps). I discovered a broken wire by the transfer case shift motor, which I soldered back together. This stopped the 4wd light from flashing.
As of now, the truck still isn't unlocking the front differential. I really don't want to take off that front drive shaft, either. When I switch from 4wd to AWD, you can hear the relay clicking and the slight sound of the motor turning, so it seems like everything is working correctly. I hate to think that it's an issue with the transfer case itself, but I figured I'd ask y'all for some second opinions on what could be causing the issue. Thanks!
