Ok so either I’m loosing my mind or something is not right. I bought a 1994 F150 from my Sister In Law. I expected it to need work. The truck is an XLT with a 5.0 8.8 inch rear 3.55 non LS rear it’s 2WD. Not sure which transmission but it’s code 19. Anyway I drove the truck back from Texas to South Carolina pulling a Uhaul trailer. By Gods grace we made it. Hahahahaha. I noticed the rear diff was leaking like a stuck pig. So I pulled the cover cleaned everything out. Rolled under the truck to find the damn pinion seal was leaking like mad also. So I got the seal and a gear puller as I did not have one. I removed the drive shaft removed the pinion nut, flange I also pulled out the oil slinger and rear pinion bearing to inspect it. The pinion bearing looked decent. Only a couple pit marks. The truck has 240k miles. The oil slinger looked like it was freaking warped. Like really warped may have been fine but it just looked wrong. So I spend 2 bucks and replaced it. Put everything back together I did the whole mark the pinion nut and count threads thing. Everything seamed to go back together fine until I freaking snapped a diff cover bolt. I have a bolt extractor on order. I have some extra gear oil so I threw some in and spun the wheels to get oil on everything so the gears do not rust up. I’m hoping I can extract the broken bolt and not have to redo the diff cover seal. Anyway while spinning the wheel I noticed something did not feel right. Well duh. Why the hell is the wheel spinning and truck is in park. I look and the axle is not moving. So I put the transmission in neutral axle spins. Da hell. So I was like screw it I cranked the engine and popped it into drive rear wheel starts spinning 30mph. I knew it has a high idle that needs fixed but damn. So I hit the breaks wheel keeps spinning breaks are squishy. Crap pop into neutral pump breaks they grab wheel stops. Place in park turn off engine. Roll under truck find the drivers side rear drum is leaking bad. Well damn. I check the wheel same thing. It’s spinning with very little resistance and the axle is not moving. The opposite wheel is moving in the opposite direction. I also grabbed the driveshaft and tried to turn it by hand while in park and it did not budge. So I’m really confused. Is something broken in the rear diff or is this normal and the parking break only works with the wheels on the ground. I don’t want to take it off the jack stands right now until I get the bolt I snapped fixed to see if it rolls. Any help would be appreciated. Thanks.

 

Please try to use separate paragraphs it just makes it easier to read so we can better understand what you are saying.

From what I read it sounds like normal open differential action as far as the wheels spinning.

Your axle vent is probably blocked, and is the root cause of all the seal failures. Replace the seals, clean or replace the vent and drive on.

 

with both wheels off the ground and trans in park, one wheel will spin and the other will usually spin the other way.
with 240K miles on the LS diff, the clutches are probably so worn out that it is now an open rear.

 

Parking brake should work with the wheels in the air or on the ground. What do you mean it doesn't work? You engage the parking brake but the wheels still spin?

 

With both wheels off the ground and the transmission in park you can spin the wheels. The parking break stops it.

I had my son hold one wheel and I tried to turn the other they would not turn. But when he let go they turned. I’m assuming that this is normal. I did not know and was afraid that I jacked up the rear end when I changed the pinion seal.

Just made me realize how much I really don’t know and how much I’m gonna learn working on this truck. I will check the axle vent thank you for the tip!

 

There, I fixed it for you.

 

Mark, the reason i typed usually is because we do not know what was done previously to the truck. if a locked diff was installed, the opposite wheel will not spin the opposite direction


but you are correct with a stock axle.