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.....
(https://lh4.googleusercontent.com/_HnhcDIddtiA/TYvIfCvAWTI/AAAAAAAAA88/6iVPwc7IHaU/s912/DSC05861.JPG)
(https://lh5.googleusercontent.com/_HnhcDIddtiA/TYvIgliPOKI/AAAAAAAAA9A/kQMm8wZC-8c/s912/DSC05862.JPG)
Loose/broken parts inside a differential never are good news...
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.......
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?
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
Good point luvrbus ....I've got access to a borescope from work. I may borrow it and give her a look.
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
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.
"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?
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.
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.
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.
Quote from: Barn Owl on March 24, 2011, 08:08:36 PM
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.
I'll try to remember to let you guys know what I find and what I decide to do.
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!
I talked with my local heavy equipment mechanic this morning, who I trust emphatically, and he said, and I quote..."Run it!". With the tire sizes the same, but considering small differences in the tire OD, there will be minimal rotational movement of the pinions about the spider. Only while turning the bus will they rotate more than normal since this is an open differential. Also, with the gear lube low and evidence to support only one washer being damaged, it is more likely that a flush and refill will do it a world of good. With that being said and the fact that pulling and rebuilding will be a major PITA, I'm opting to go that route and recheck it at a later date.
Oh yeah, the material is soft. Very soft. So soft that it doesn't register on a Rockwell hardness tester. It could have been, and most likely was, originally case hardened or nitrided, but it ain't no more. I'm asssuming that the lack of a proper level of lubricant has led to overheating thus removing the level of hardness bestowed upon it. Also, my borescope is not available.....so I'll pass on that also. Thanks for the suggestions thus far though....
I'm certainly no expert but had a similar situation. When I took off the oil pan to seal it up better I found a small piece of metal that looked like it might be a gear tooth. So I went to the local DD dealer with piece in hand.They had an 8/71 apart and he showed me where it probably came from. The inevitable question was "would it hurt. how long till it failed etc" and the expected answers "could fail in a mile or last forever". So I took the trans off and it was a tooth off one of the cam gears. Not expensive as I got the gears off a wreck for $25 bucks each.BUT, the problem is every time you drive it you will wonder when it will let go. Or every strange noise will drive you crazy. However, if you can scope it that might put your mind at ease.
Good luck
Fred
My next project is to replace my differential oil. Hope I do not find any mystery parts! What weight and how much for the 4106?
Thanks
TM
I used Mobil 85W140.....
Billy,
Any idea on how much it takes??
Thanks
TM
Mine took around 2 1/2 gallons.
Awesome Thanks!!! What is the best way to purchase that much gear oil? Perhaps in bulk or by the gallon???
TM
some places sell 2 gallon plastic gear oil containers, such as the farm store. i normally buy 5 gallon cans for my luber, but in your case i would prob buy 2 two galloners... cause u dont use it all the time.