4X4 trouble

[Crmsntide27]

This has happend a couple of times. I was trying to pull my truck to the side of the road one afternoon before I walked to my blind. There was a small ditch to my left, nothing big at all. Anyways, I pulled in there and started to back up and while in 2WD my back right tire would only spin. The truck was sort of inclined where the truck was squatting down on the left tire. I put it in 4X4 and was still having trouble getting traction. It was almost like there was no power getting to the front wheels. When I put it in 4X4 I can here it shifting in the transfer case. My truck is an FX4 so I'm pretty sure both rear tires should be spinning at all times.

[Davey~do]

Originally Posted by Crmsntide27

I put it in 4X4 and was still having trouble getting traction. It was almost like there was no power getting to the front wheels. When I put it in 4X4 I can here it shifting in the transfer case.

The ESOF point of failure is generally the vacuum system. They pump isnt able to generate enough vacuum to lock in your front hubs. Generally thats from a vacuum leak where the hose enters the hub or from the seals leaking. Inspect your hoses where they enter the hub and if you dont find anything there, use a vacuum gauge to try to hold a vacuum on your seals. That should tell you where your issue is. There can also be a couple of other causes but these two will be the most common. Eliminate them first. Other than that, make sure you lock your hubs in manually before you get in a situation you could get stuck in. It wont hurt at all to just leave your hubs locked in the whole time you are on your lease.

Originally Posted by Crmsntide27

My truck is an FX4 so I'm pretty sure both rear tires should be spinning at all times.

Most likely it is. Check your door tag and look for "373L" I think it is. The "L" indicates limited slip. Personally, I think 75% of the problems with the limited slip systems is the fact that Ford puts in too much anti-friction additive (8 oz. or so I think?) to eliminate customer complaints with the binding in turns. Drain your differentials and replace with fresh oil of the correct weight and start off with half of what Ford calls for (4 oz. I believe). Try that, and if your differential binds any in turns just add a bit more additive till the binding problem goes away. Either that or just use a good synthetic like amzoil of the correct weight that doesnt need an additive.