My Rear End has a Crack In It

[68neverlate]

Sorry guys... couldn't resist!        

Although this may be normal for most of us, I don't think it's all that healthy for my car!     

So, to the subject... my rear-end really does have a crack in it!  I bought my '68 Charger about a year ago, long distance, so I had a shop look the car over before buying.  They noted a small leak from the rear-end, but didn't give any reason as to why.  I was finally able to invetigate this last night (I had the wheel off to do a little brake work) and I noticed that there was a crack at the bottom of the pot (about 2" long) that someone had attempted to fix with a weld.  I confirmed that that's where my leak was coming from.  I'm dissapointed that the shop didn't say anything about the crack in their inspection report... maybe they were too "embarrassed" to include.       

I'm a little green under the gills when it comes to rear end and axle, so I was hoping that you experts on the subject could provide a little guidance (keep it clean guys!).  Am I pooched or is the rear-end repairable?  Is it ever advisable to weld a crack in your rear end....  , or is there a better way to deal with this?  Won't a weld eventually just crack again under the stress?  Do I have to replace the whole rear axle? 

Whatever you guys can advise would be appreciated.

Cheers,     

 

[b5blue]

I'm not touching this one......

[68neverlate]

Yeah... can't blame you!  I just reread my initial post... it is pretty bad, isn't it.         

OK, all innuendo aside... I am interested to hear what you guys think is the best way to resolve this CAR issue...       

[John_Kunkel]

I noticed that there was a crack at the bottom of the pot (about 2" long)

What is a "pot"?

[68neverlate]

I noticed that there was a crack at the bottom of the pot (about 2" long)

What is a "pot"?

Sorry John... wasn't sure how best to describe it.  Is it the diff housing (holds the gears)??     

[68neverlate]

I just tried searching the site for threads containing similar issues and was unable to come up with anything.  Has anyone ever seen or heard of a cracked 8 3/4" rearend before?   

I'm in Codyland and 8 3/4" rearends are not exactly falling over the autowreckers fences up here, so I'd like to know if it's possible to repair the one I have or if I have to start looking for a replacement. 

Appreciate whatever help anyone could give... 

Cheers,          

[flyinlow]

Is the carrier weldable ? probably.  Is it worth it ? depends.

Is it the gear you want? suregrip? are the last three numbers 742 or 489 on the carrier? quiet?  If not, I would be shopping for a new or good used carrier. (sometimes called a pumpkin,pig or I guess a pot in Canada)   

[68neverlate]

Thanks for the lingo lesson flyinlow... I think I discusted John right out of this thread with my ignorance!           And nice jab on the Canadian reference!!      

So, back to the issue... yeah, all excellent questions!  Right now, from what I can determine, I think I have 3.55s on an open diff.  I counted the number of revolutions on the driveshaft with one full turn of the tire and it went around 1.75 times.  That's what leads me to believe it's open.  From my understanding of the threads on determining gear ratios, one turn of the tire on a sure grip would have turned the driveshaft at least 2.75 times.  On an open, you need to turn the tire 2 times around to get your ratio (2 full turns on the tire @ 1.75 turns on the driveshaft = 3.55). 

If that's right, I don't mind that combination.  I'm not racing the car nor am I tromping on it around town.  Besides, if I did want to change it up, I'm guessing I'd be paying more for shipping to get the parts here than I would the cost of the parts themselves. 

So I guess I have a rear end to remove...     

[flyinlow]

If you post some pictures , maybe some of the welders can give you their opinion. I think you need to use a nickle alloy rod  and know more about welding than I do.

Good luck.

[68neverlate]

Thanks for the advise... took some pictures this afternoon.  Just need to upload from the camera and post.  I finished my brake work and re-checked the gear ratio and the carrier.  It looks like I'm closer to 3.25 turns on the driveshaft... so probably 3.23s.  The carrier is a 742.  For what I'm going to be doing with the car, I'd be happy with that set up.  Not a sound coming from the back at all... its dead quiet. 

The crack is a bit longer than I first thought... looks to be the whole underside of the pumpkin (how's that for terminology!).       Visual soon... I haven't posted any pictures on the site yet so not sure if I'll run into any issues.  Hope welding is still an option... 

Cheers,   

[68neverlate]

OK, I finally got the photo uploaded so we'll give this a try.  Any welding experts out there able to provide an opinion about whether this is repairable or not and if so, how best to tackle??   

[68RED4SPEED]

Do you mean this one in the housing, they are supposed to be like that from fabrication, does it leek in the weld or from the gasket area? If its the weld thats leaking there should be no problem to reweld it.

[68neverlate]

Wow... I would have never guessed that would have been made like that.  A whole lot of ignorance on my part... I learned something today.  I just assumed it was a crack...               

So, no, I'm not sure that the leak isn't coming from the seal... is what I mistook for a crack at the bottom of the pumpkin an actual fabrication weld or is it just an external seam from a cast?  If it's a weld, has anyone ever seen this leak before or am I pretty much looking at a seal issue (diff to housing)?   

The drips were forming at the bottom of this protrusion... but it is also the lowest point on the rear end too, so leak could really be coming from anywhere.

[Troy]

I had one leaking around a stud (seal went bad) and it would drip from the center like that because, as you noted, it's the lowest point. I would guess that yours is the same - but I suppose it could crack the housing.

Troy