Leaky rear diff

[pbnj22]

00 explorer 5.0 with 127k
I have not driven it a lot lately and after pulling it out of the garage I noticed the rear diff was leaking at first it appears to be a bad gasket because it is all wet on the bottom of the diff in a half moon shape so the bottom and both sides of the diff but after looking more it is also all wet by the back portion of the drive shaft so is there another spot it could be leaking from? I would think that if it was splash from the gasket leak that it would be wet behind the original leak and not in front with the wind of driving forward and what not
Also how do I check the fluid level? Is there a built on top that I couldn't see?
Or do I need to take off all 8 or so bolts and drain it change gasket and put it back?

 

[delexploder]

Pinion seal

 

[pbnj22]

That does not sound like fun replacing... Might have to pay a shop... Especially sine I don't have the tool to measure the inch pounds of the nut and re tighten it to that...

 

[delexploder]

Yea if you dont have a strong impact gun you'll play hell getting that nut off, the seal itself is very easy.

 

[pbnj22]

i have a decent impact, not a great one.. but im more worried about measuring how tight its on there and then putting it back on that same tightness. I read somewhere else on here that it is crucial for that. i think ill just get a few shop opinions on it and a few estimates

 

[rizzjc]

Getting that nut back on just right is tough. At least, I screwed it up, and eventually had a lot of backlash. Wound up putting in a junk yard axle, and then eventually had mine rebuilt by a local driveline shop. When I had tried to just get a shop to set the preload on it right, they wanted to charge me for a complete rebuild.

 

[imp]

i have a decent impact, not a great one.. but im more worried about measuring how tight its on there and then putting it back on that same tightness. I read somewhere else on here that it is crucial for that. i think ill just get a few shop opinions on it and a few estimates

The degree of tightening of the nut is not the important point: the amount of preload it places on the two bearings is of utmost importance. Too little, the gear teeth wiggle around under load, become scored, and can fail. Too much preload, and the pinion bearings overheat, and fail prematurely. The happy medium is accomplished by placing a very sturdy, but collapsible spacer called a "crush washer" between the two bearings. It requires considerable tightness exerted by the nut to squeeze it down until finally ALL the clearance between the bearings is taken up, and then additional tightening, just a bit, places preload on the bearings. The crush washer should always be replaced with a new one whenever the nut is loosened, for whatever reason. imp

 

[rizzjc]

Umm, but isn't that crush washer on the inside?

 

[imp]

Umm, but isn't that crush washer on the inside?

Remove nut, and washer, if there is one, then remove the U-joint flange, then pry out the oil seal, then remove the oil slinger washer, if there is one, then the hard part: pull out the inner cone & roller assembly of the front bearing (facing front of truck). Usually, they are a sliding-fit on the pinion shaft, once the bearing is slid outward, you will see the crush washer behind it. It will slide out easily.

So, yes, it's "inside", right between the two bearings. But then, isn't everything "inside"? imp

 

[pbnj22]

The degree of tightening of the nut is not the important point: the amount of preload it places on the two bearings is of utmost importance. Too little, the gear teeth wiggle around under load, become scored, and can fail. Too much preload, and the pinion bearings overheat, and fail prematurely. The happy medium is accomplished by placing a very sturdy, but collapsible spacer called a "crush washer" between the two bearings. It requires considerable tightness exerted by the nut to squeeze it down until finally ALL the clearance between the bearings is taken up, and then additional tightening, just a bit, places preload on the bearings. The crush washer should always be replaced with a new one whenever the nut is loosened, for whatever reason. imp

Jesus.. I don't know if I even trust a shop to do this let alone myself

 

[rizzjc]

Remove nut, and washer, if there is one, then remove the U-joint flange, then pry out the oil seal, then remove the oil slinger washer, if there is one, then the hard part: pull out the inner cone & roller assembly of the front bearing (facing front of truck). Usually, they are a sliding-fit on the pinion shaft, once the bearing is slid outward, you will see the crush washer behind it. It will slide out easily.

So, yes, it's "inside", right between the two bearings. But then, isn't everything "inside"? imp

Well, I've replace the seal before, and never knew, or realized, that anything could come off from the outside other than the nut, and seal.

 

[Flash]

That does not sound like fun replacing... Might have to pay a shop... Especially sine I don't have the tool to measure the inch pounds of the nut and re tighten it to that...

Buy a torque wrench from Harbor Freight, once you've got one you'll always use it.
They're especially good for doing the lug nuts because of the half metre long handle.

 

[delexploder]

If you can hold the flange with either a proper spanner wrench or what we use is a giant pipe wrench and if you can get the nut off, just count the threads showing or measure them before removing the nut and return it to the same spot, if you are not doing a full rebuild this will be fine, oh by the way I have spent most my adult life working for one of the best mechanics on the east coast, he is well known for rears mostly 9s but we have done tons of tin plates ( 8.8) and motors, point is if a customer has a leaky pinion seal this is how we do it and never had a problem,

 

[pbnj22]

got a quote from a ford dealer at 220. Think I am going to jump on it because i dont want to wait anymore and lose any more fluid and cause bigger problems. unfortunately its a little harder to check and top off rear diff fluid than engine oil

 

[delexploder]

Wow is that just to do the seal?

 

[pbnj22]

Wow is that just to do the seal?

yeah. is that a lot? that is a ford dealer so i figured that would be on the high end and i can call a few shops tomorrow and find someone a little more reasonably priced... want it done right though

 

[imp]

yeah. is that a lot? that is a ford dealer so i figured that would be on the high end and i can call a few shops tomorrow and find someone a little more reasonably priced... want it done right though

Ask the Dealer's Service Manager if that high price is due to properly setting the pinion bearing preload, i.e., do they replace the crush washer? imp