View Full Version : Holy Diff Carnage Batman!
fargo59
03-24-2009, 07:43 PM
so i finally get around to tearing down Jaak's old diff to replace the very noisy pinion bearing, and while im removing the rear pinion bearing i see this:
http://farm4.static.flickr.com/3624/3382949279_f0e7562dc3_b.jpg
http://farm4.static.flickr.com/3454/3382938531_961cf9f395_b.jpg
every tooth except for 3 are radially fractured. has anyone seen this kind of stress before in the 215 housings? i sure haven't.
Hemi31
03-24-2009, 07:44 PM
OOOF....that was about to be very ugly!Ever seen Jaak drive?;)
imahemi
03-24-2009, 07:44 PM
wow chris
Sharp Charge
03-24-2009, 07:44 PM
that can't be healthy.
fargo59
03-24-2009, 07:48 PM
OOOF....that was about to be very ugly!Ever seen Jaak drive?;)
seen? i went for a couple drives with him last week. :thumbs_u:
just wondering if anyone has seen it before. maybe an engineering opinion other than "shock load"
bigjim
03-24-2009, 07:53 PM
WOW, Thats some tough material to have NOT shattered when it originally happened!
Token
03-24-2009, 07:56 PM
That does look really nasty.... I know it's of no help, but I've got to agree with Erik on this one.
maybe an engineering opinion other than "shock load"
Welp, don't know bout that.
But shattering teeth on Jaak's rear end.......
MAN!, there has got to be a joke in there someplace!!!. :boohoo:
sugar-tj
03-24-2009, 08:19 PM
Welp, don't know bout that.
But shattering teeth on Jaak's rear end.......
MAN!, there has got to be a joke in there someplace!!!. :boohoo:
maybe, but, i'm not goin there....:bahdumcha:
PowerWagon896
03-24-2009, 08:22 PM
Welp, don't know bout that.
But shattering teeth on Jaak's rear end.......
MAN!, there has got to be a joke in there someplace!!!. :boohoo:
But shattering teeth on Jaak's rear end.......
Must be a real "harda$$".:banana:
fargo59
03-24-2009, 10:26 PM
yep, there's cam making rear end jokes.... :P
PaCharger
03-24-2009, 10:36 PM
Hmmmmm. Not on a 210mm. :)
Posted via LXFMobile
GasGunR
03-24-2009, 10:43 PM
Those teeth had to be flexing somewhat in order to do that... If it was an impact, you'd think you see a failure before all the teeth were cracked like that.
fargo59
03-24-2009, 10:44 PM
no, its not oh holy diff destroyer, :not_worth:not_worth:not_worth:not_worth
does this give you new hope with that 215 you just installed?
given that very few other people have had a 215 failure, i would say that they hold up quite well. this is an "off" case i believe.
PaCharger
03-24-2009, 10:55 PM
Chris - I have two on my workbench. 1 I put 100 miles on while it was failing - the other was spontaneous crush.
So.....the question is - were there bits and pieces grinding like a coffee maker for a while on jaaks ride? I know the answer....
Posted via LXFMobile
tank8289
03-25-2009, 01:52 AM
Those teeth had to be flexing somewhat in order to do that... If it was an impact, you'd think you see a failure before all the teeth were cracked like that.
I agree that the teeth definately had to be flexing in order to crack like that. I think that could be easily fixed by hardness treatments if we encounter more of these problems. But as of right now flex is probably the best thing if theyre not strong enough, flex is better than break!
Trojan
03-25-2009, 02:02 AM
Way to go jaak! Thats pretty crazy!
dudeiwin86
03-25-2009, 02:08 AM
all i see is a grenade with the pin pulled and the time is ticking away.
good thing you got that sucker out of tehre ;)
Super T
03-25-2009, 08:51 AM
side note, where did you find a new pinion bearing?
Posted via LXFMobile
fargo59
03-25-2009, 09:28 AM
i havent. even the mercedes part numbers on the case dont correlate to any relevant mercedes cars that my local dealer could find. i was going to assume an E63 or something along that line. i just wanted to tear it down to see how bad it was. since there is a new diff assembly in jaak's car, this looks like a good contendor for 3.23's or if anyone wants to sell some 3.06 ring and pinions to me...
this one will probably go in my car when im done. i just want to have it done to my specs when all is said and done.
hemiwagn
03-25-2009, 09:44 AM
oh boy
now I have to wonder how mine is.
I certainly have had lots of spin/grab cycles with the high strength axles, especially when I was learning how to do burnouts... I wonder if the diff was/is the next weak link or not....
seanol
03-25-2009, 09:50 AM
Could a tight backlash cause this? If you have the ring gear down low on the root of the pinion that could put added stress on the root of the teeth?
It looks like all the cracks are coming from the root and on the drive side.
If it was a hardness issue I think you would have lost a tooth or wiped a face. It seems that this is the type of failure mode you would see with a tight gear mesh and overload.
Just my .02,
Sean
fargo59
03-25-2009, 10:32 AM
i dont think so. as i said, a pinion bearing was going on it too. could have been deflecting the pinion and stressing the teeth. usually a tight backlash will knife edge the teeth on the pinion.
KGBPro
03-25-2009, 10:42 AM
i have a question.....
what the heck would cause this?
seanol
03-25-2009, 10:53 AM
Fargo,
My experience is with industrial gearboxes but I have found that when the gear clearance is too tight the contact patch moves down towards the root and starts to undercut the root of the drive gear.
Is it different on a rear differential?
How did the ring gear look?
Was the lube burnt?
Thanks for the tip on knife edging.
Sean
Trojan
03-25-2009, 11:15 AM
Fargo,When I bought the axle seals for my Challenger at MBZ the guy told me a C30 class. Not sure if he was right or wrong but the seals fit and are on my Challenger now.
fargo59
03-25-2009, 11:23 AM
thanks for the tip chris. i've been having one heck of a time with the local dealer. you'd think it would be easier, but as soon as you mention "dodge magnum" they usually delete the email, or hang up. LMAO.
nhdave
03-25-2009, 11:59 AM
oh boy
now I have to wonder how mine is.
You and me both now that I have a midrange sounding hum at 85mph..
Wow, that jaak guy is an animal!!!!
Now on the street, I wonder if street tires would give enough traction to be the cause of that. On the strip, even before my last hard runs last year, I was hearing the bad pinion bearing. So the question on my mind... Did the bad pinion bearing cause a deflection in the yoke which altered the loading on the pinion, causing the stress under high load?
As for the track, I would stage, load the drivetrain a bit to take out any slack, let the engine drop to idle (about 50 rpm over stock idle the way I had it at the track) and then flash the torque converter to try and bring up the rpm in to the power band as much as possible and get a good launch.
Have my 60 ft times been better than everyone else's? No... So unless others start pulling apart their diffs and finding the same thing, I would tend to believe these stress cracks are a result of high loading with a bad bearing, not from how I drive the crap out of the car.... But who really knows?
Good thing I changed it though.... I wonder how long the replacement's going to last?
Now speaking of fluid, It did get changed out at Hemiwagn's last year. I seem to remember the fluid looking worse that I would have expected at that mileage, so this diff's been on it's way out for quite some time. It's not just a sudden one shot incident.
I'm looking forward to seeing it, and the bearings, first hand Chris. Thanks for posting this, and I'm sorry there isn't more good parts in there, I was hopeful you could have just dropped in new bearings and have a good diff!
You and me both now that I have a midrange sounding hum at 85mph..
Hmmm.... Sounds familiar.
At first I thought it sounded like a bad wheel bearing, but it didn't change with lateral forces (cornering) so I started thinking inboard. The service manual gives some good advice on troubleshooting and I could tell which pinion bearing it was, by the SM's guidance. However I'd like to confirm that with an actual look.
Just as well I didn't run around getting bearings, considering the damage... :tinfoilhat:
fargo59
03-25-2009, 01:00 PM
no worries Jaak. there are still many things i can do with this case. with richmond making 3.23 gears for the 215 housing, im sure someone will be selling their 3.06 ring and pinions.
stevesrt8
03-26-2009, 02:31 PM
I have seen similar damage in an old ten bolt GM rear end in a drag car.
We decided it was the result of deflection of the bad bearing.
Kudos to the jaakster!
ilovetrains
03-26-2009, 04:56 PM
Since the cracks are radial and virtually uniform throughout the piece, that looks like a casting failure to me. Impact would have affected a few teeth, not the whole gear.
I did not stay at a Holiday Inn Express last night - but I have blown up a few rear (and front) ends in my off road adventures.
CoburnRacing
03-26-2009, 05:23 PM
That is a nice conversation piece. Just leave it on the coffey table.
RobAGD
03-26-2009, 05:32 PM
Fargo - the newer modle year AMG E55s have the 215 and the older model E55 has the 210mm
C30 also works
-R
That is a nice conversation piece. Just leave it on the coffey table.
Yeah, I'd like it back from Chris unless he's particularly attached to it... :)
fnkychkn
03-26-2009, 09:22 PM
wow! those are some nasty cracks.
i've seen plenty of worn pinion bearings where the gear was loose in the housing but never seen one crack like that. of course, jaak wasn't driving them.
the only 215 i've had apart looked like this: http://lxforums.com/board/showthread.php?t=119331
And if only I had caught on earlier, I could have had it replaced under warranty. LOL!
GasGunR
03-27-2009, 11:58 AM
Fnky's thread above had a post, (11), in it that bearings were available from RennTech.
It was posted by Lou1355.
Fnky's thread above had a post, (11), in it that bearings were available from RennTech.
It was posted by Lou1355.
Yeah, and they've been unresponsive to Chris (Fargo)
fargo59
03-30-2009, 06:42 PM
yep. they havent liked me too much. im just going to buy a whole lot of coffee for the local MB dealer and see where it gets me.
Hey Jaak, i had planned on leaving you a new conversation piece (the pinion) but i forgot it at home on friday.
Cool, Chris, thanks.... Considering what the replacement diff cost me it would be cool to have it.
Got the pinion from Chris and had a look at it today. EVERY TOOTH is cracked at the root.
And the cracks follow the root as well, so it's quite bad. I'm very lucky I didn't have it come apart.
This one, you can see, is ready to let loose.
http://i41.photobucket.com/albums/e266/srt8jaak/Pinion/jaakpinion006.jpg
http://i41.photobucket.com/albums/e266/srt8jaak/Pinion/jaakpinion005.jpg
http://i41.photobucket.com/albums/e266/srt8jaak/Pinion/jaakpinion003.jpg
Nightshade
04-05-2009, 10:46 PM
should almost send that the chrysler engineering and ask them WTF..
should almost send that the chrysler engineering and ask them WTF..
Yeah, doesn't everyone put DR's and 1,000 HP halfshafts on their SRTs?
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