I usually hang out on the 7.3 side but just recently pic up a 06 f250 king ranch, it's a nice looking truck. I took it to a mechanic to have it checked out before I bought it and he said all looked good except for a small oil leak at the rear pinion seal. So I said ok drove around for a while and stopped to put petro. While the pump was pumping I looked under the truck to check out that small leak. I was shocked at what had been obviously leaking for a while and was caked up all over the pumpkin. So I drove it home with my fingers crossed. Picked up a seal and started to take things apart. Now I'm no mechanic and have never replaced a rear pinion seal. But I've done s lot of work on my 7.3 and felt confident that I could do it. So every thing came off put the new seal and bolted up the drive shaft. Took it for a test drive and I felt a little vibration. Checked it out and realized the four 12 mm bolts were a little loose so I cranked them down good. I decided to check the level of the gear oil so I in did the plug and stuck my finger in there. Nothing! That's right nothing! Lots of fine shavings on the plug. Went and picked up some gear oil and started to unbolt the cover. This is what I found.




So I have a few questions.?

Are the markings fresh? Could this have happened when I took it on a test drive after I replaced the seal or was it a problem before? Before I removed the pinion nut I counted the threads to make sure I put it back like it was. Besides kicking my self and the mechanic in the *** what should I do? Am I screwed? Can I just refill with gear oil and call it good?

Sorry for the long post and the bad grammar. Doing all this on my phone.

 

If there are no chipped teeth you may have caught it in time. First, I'd pull the 4 bearing cap bolts and pull the center section. Then remove the pinion nut, yoke, and finally pinion gear and bearings out of the rear housing. I'd replace all bearings and races along with the seal. Put all the shims back wherever they come from and warm your new bearings and drop them on. You must use a new pinion nut. It's not worth it in this case to try to use the old one. That nut loosening or a pinion bearing failure is probably what got your truck in this mess. You must set the preload torque on the pinion bearings. Then you can reinstall the center section and check backlash pattern. Finally reinstall the cover and fill with oil.
If this is too much for you have a reputable driveline shop do it. It's not rocket science for the experienced but can be done wrong and end in needing new gears too. Read up on setting up ring and pinion gears before attempting. It would help if you had a qualified friend to help.

 

87crew, thanks for you reply. That is a little intimidating for my level of experience. Will just have to bite the bullet and get some one to take care of it.

Thanks again.

Gilbert

 

pinion depth is set too deep need to pull it back some look at the pattern on ring gear

 

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What he said

 

Did the driveshaft flange/yoke easily slide back onto the pinion on reassembly? And which method of retorquing the pinion nut did you use?
It looks a lot like something on the pinion shaft didn't completely sandwich together when reassembled and is letting the pinion gear be sucked back into the carrier.

 

After I replaced the seal I took it for a test drive. Nothing to fast but i did feel some vibration. When I rechecked I noticed that the drive shaft was not completely snugged up to the flange. there was a small gap between the drive shaft and the flange. I torqued down the bolts and closed the gap. I wondered if the vibration from not being completely seated in the flange caused the damag? Before I took the nut off to replace the seal I counted the threads. When i was done with the seal I put the nut back on and made sure I had the same number of threads showing. Before I replaced with new oil I cleaned out the gears and housing with brake fluid. When I was done I had my wife drive it while I sat in the back with my ear to the bed listening for any noise or vibration. So far no noise or vibration. Been driving 40 hwy miles every day since. No problems so far.
Hopefully I dodged a bullet for now. Thanks for all the help.