A rear end question for any 4106 experts out there....

[bwze]

I'm in the process of changing out my radius rod and stabilizer bar bushings and decided since I was in the neighborhood that I'd go ahead and service the rear end lube. So, I pull the plugs and start to drain the oil. First thing I notice is that the amount of oil I was expecting to find and what's in my drain pain don't seem to add up. Next, I find what's pictured below (notice how the two pieces seem to fit together) in the bottom of the hog head. After an examination, I feel that what I have here is a partially failed or completely failed spider pinion thrust washer (also pictured below.....X in the exploded view). Now I know that the mechanic side of me wants to tear it apart and fix it, but the logical side says......"should I be worried?" I mean, this bus is 46 years old, was running low gear lube to start with and I don't plan to take any cross country trips anytime soon. I'm thinking, give her a good cleaning out with some Varsol, button her back up, fill her to the plug with fresh 85W150 and let her rip. Given all this, what say ye ole knowledgeable 4106 (and other bus) owners.....

[pipopak]

Loose/broken parts inside a differential never are good news...

[bwze]

Understood.........but how long has it been this way..........could've been many years.

On the other hand, could've been last weekend.

Either way, what are the ramifications of not fixing it and letting it go.......

[artvonne]

  Its not going to get better, and in fact, could destroy itself rapidly beyond any possible repair within a very short time. It might go another 1000 miles, but I wouldnt bet on it. So the question really comes down to where you want to fix it at. Where you are now, or somewhere in the middle of nowhere, trying to call out on your cell phone in a no service area for a wrecker?

[luvrbus]

Before you let these guys talk you into pulling the differential  borrow or buy a Borescope and take a look HF sales one for less than 100 bucks you may need a little more light for theirs, those parts could have been there for years from a previous repair you never know

good luck

[bwze]

Good point luvrbus ....I've got access to a borescope from work. I may borrow it and give her a look.

[TedsBUSted]

Hmmmm

I'm not sure what that is, but I don't believe it's X or S.
Both X and S would be trapped within the differential case and would have a tough time swimming out while so much intact.

Is the mystery part hard like a bearing or shim or soft like an oil slinger or seal housing?
How big is it?
I wonder if it came in from the wheel end?

Ted

[bwze]

Soft, and about 2 1/2" end to end.

I see your point about making it past the case, but I did find a couple of other pieces that were smashed a good bit thinner than the others..............?....maybe a pass through the gear mesh?

Agreed, can't disregard the ends of the axles.

Oh yeah, and it has a curved profile. Just like the picture of the thrust washer.

[.030over]

"Soft, and about 2 1/2" end to end" is definitely not a spider gear thrust washer. They are hard steel washers that keep the gears from wearing the case. How soft are we talking? Like rubber?

[bwze]

No, soft as in not bearing race or gear consistency. Soft as in mild steel possibly?

If I can remember, I'll take a piece with me to work tomorrow and see what the hardness measures.

[.030over]

I got you. You could be right on the washer. Looks like a bevel or lip on the OD. I'm no expert on these but there is very little inside the smaller diffs that I do, that is not pretty hard. I can say for sure ... it's better where it is now than still in there.

[Barn Owl]

I wouldn't be much help, so I will have to wait for you to educate us after you get yours. I have heard that the rear ends are one of the major items that are not impossible, but yet a challenge, to find. What ever you do don't chance messing it up. Good luck.

[artvonne]

What ever you do don't chance messing it up. Good luck.

  That was my thinking. While I agree its possibly left over junk, or it could of come from the wheel ends, it still needs to be found out before you head for Alaska.

  One of these days im going to buy a gastro or proctoscope off eBay. There have been several times where the dang thing would have more than paid for itself in one use. You could look all over inside that diff with one of those.

[bwze]

I'll try to remember to let you guys know what I find and what I decide to do.

[DMoedave]

i am not even close to any kind of expert, but if you can jack and block her up and spin the tires and check for any bearing up and down movement on the tires and any clunks when turning back and forth etc it might help you make a decision. I found large chunks of metal on my first differential oil change! It was still going10 years later!