My Freekin Leakin rear Diff.... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ChevyDude · 06-15-2005, 09:27 AM

You guys might remember that my K-10 exploded it's rear end and I had it re-built with a new Eaton Posi and 3.73 Motive Blue Line gears. I thought all was well back there but lately have been noticing a small drip when approaching the truck. My day off was yesterday so I stopped by NAPA and bought a new rear cover gasket, gear oil and posi additive. Removed the cover, cleaned it up, installed the new gasket, and re-installed cover. Tighten all the bolts and filled pumpkin. 10 min. later,,,,Freekin drips!!!! I climb underneath and fine on the back side a small crack about 1/2" long where the leak is coming from. CRAP!!!!! I dabbed a bit of Permatex gasket sealer in the crack and as of this morning no leaks, just not sure how long the Permatex is going to hold up. Question is, should I wire wheel the area and JB Weld (permanant steel glue) the crack, or should I clean it up and touch a MIG to the crack?

Any suggestions would be great.

Alex

**Yukon Jack** · 06-15-2005, 09:40 AM

Where is the crack located? On the back side of the differential?

Syco67 · 06-15-2005, 09:40 AM

Is the crack on the cover or the housing. If it's just the cover, JB weld or Mig, whichever you prefer should be sufficient, or if there is a drivetrain shop near you, see if they have any old covers laying around, I have gotten a couple for free. If it's the housing, I'm not sure what to tell you.

ChevyDude · 06-15-2005, 10:03 AM

The crack is in the housing. On the front side of it towards the cab. It is at about the fill plug level but on the other side of the fill plug. This must of happened when the original gears and posi unit exploded. What to do???

blazerparts · 06-15-2005, 10:12 AM

Maybe get a skid plate for the diff. Then occasionally when at Wal Mart parking lot, squeegie the accumulated drips out.

ChevyDude · 06-15-2005, 10:31 AM

Quote:

Originally Posted by blazerparts

Maybe get a skid plate for the diff. Then occasionally when at Wal Mart parking lot, squeegie the accumulated drips out.

Well I hope you were making a joke

, I can handle that, but really I would like to know of a viable way to fix this.

I'm thinking I could drain the pumpkin and spark a Mig to the small crack and fix it for good. Anyone else have any thoughts?

blazerparts · 06-15-2005, 10:34 AM

Can you weld a cast material?

ChevyDude · 06-15-2005, 10:50 AM

Not sure??? Maybe JB weld glue is the way to go. The Permatex is still holding but probably won't last. Just seems like a shame to have to buy a whole new housing for such a small crack. I dunno???

**68 Stepside** · 06-15-2005, 12:14 PM

Welding cast is no easy feat. Even when you do a good job welding cast, I've seen it crack right next to the area that's been welded. Lincoln Electric has a nice page, all about welding cast. Here's the link: http://www.lincolnelectric.com/knowl...ronpreheat.asp

Personally, I would try the jb weld. As long as you get the surface throughly cleaned, you should have no problem with it. Good luck

fastwillie 696969 · 06-15-2005, 12:15 PM

yes you can weld cast iron but its cost alot your best bet it to do a jb weld fix and paint over it

71Dragtruck · 06-15-2005, 12:36 PM

To fix cast you either have to brase it ( not as strong ), or pre-heat it and DC weld it with nyerod, a nickel rod used for cast. The weld will be ugly it flows like crap, and you have to pound the weld down before it cools and cracks ( cast will shrink as it cools faster than the weld ). It has been done with regular rod and pre heat, not sure on that though.

ChevyDude · 06-15-2005, 12:59 PM

JB WELD is gonna be the ticket. I once fixed and 14' aluminum boat with pin holes in a hundred places with JB Weld. Worked great.

70c10 · 06-15-2005, 01:05 PM

Alex, maybe you should take it back to the shop that did the work and ask them how they would fix it. I guess they didn't notice it while having it apart. Maybe they will cut you a break and do it a little cheaper than normal if it's not that big of a deal.

71Dragtruck · 06-15-2005, 01:07 PM

Keep a close eye on it, it would be a shame if it cracked all the way and took out your new gears.

chickenwing · 06-15-2005, 02:47 PM

My first worry is if the crack will get worse. No experiance with diffs but Im pretty sure I'd be mad that the shop did not verify the housing was rebuildable. They knew you blew it up. Maybe the shop will swap it to another housing for you for the price of the housing.

Any one that can comment on how hard/easy it is to spot cracks prior to rebuild? Are you supposed to look for cracks? Common ya gotta check, right?

muddbugg72 · 06-15-2005, 05:42 PM

i have heard of drilling a small hole at each end of the crack to keep it from running then jb weld. i have a front diff doing the same thing and when i get ready to install it thats what im going to try. l

chickenwing · 06-15-2005, 05:56 PM

I've been trained to do that for sheetmetal...

cduster · 06-15-2005, 09:10 PM

My suggestion was going to be to stop drill with about a 1/8th inch drill on both ends of the crack, grind a v-notch over the crack, wipe it down with a good cleaner/degreaser (even use some ether, it will work good) then J-B Weld and paint. This has worked for me before.

Dan

ChevyDude · 06-17-2005, 10:01 AM

Well, The Permatex has stopped the leak. However, I am going to wire wheel the area clean and drill small "stop" or "control" holes at each end of the 1/2" crack. JB weld will fill and seal it. That's the best I can figure. Thanks Guys, You all rock!!!

06-15-2005, 09:27 AM	#1
ChevyDude Senior Member Join Date: Jun 2003 Location: Westminster, CO Posts: 3,071	My Freekin Leakin rear Diff.... You guys might remember that my K-10 exploded it's rear end and I had it re-built with a new Eaton Posi and 3.73 Motive Blue Line gears. I thought all was well back there but lately have been noticing a small drip when approaching the truck. My day off was yesterday so I stopped by NAPA and bought a new rear cover gasket, gear oil and posi additive. Removed the cover, cleaned it up, installed the new gasket, and re-installed cover. Tighten all the bolts and filled pumpkin. 10 min. later,,,,Freekin drips!!!! I climb underneath and fine on the back side a small crack about 1/2" long where the leak is coming from. CRAP!!!!! I dabbed a bit of Permatex gasket sealer in the crack and as of this morning no leaks, just not sure how long the Permatex is going to hold up. Question is, should I wire wheel the area and JB Weld (permanant steel glue) the crack, or should I clean it up and touch a MIG to the crack? Any suggestions would be great. Alex __________________ Alex 1971 Lil' Red 350 SBC 700R4 Last edited by ChevyDude; 06-15-2005 at 09:59 AM.

06-15-2005, 09:40 AM	#2
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,684	Where is the crack located? On the back side of the differential? __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14

06-15-2005, 09:40 AM	#3
Syco67 Registered User Join Date: Jan 2004 Location: Boise Posts: 64	Is the crack on the cover or the housing. If it's just the cover, JB weld or Mig, whichever you prefer should be sufficient, or if there is a drivetrain shop near you, see if they have any old covers laying around, I have gotten a couple for free. If it's the housing, I'm not sure what to tell you. __________________ If at first you don't succed, break something!

06-15-2005, 10:03 AM	#4
ChevyDude Senior Member Join Date: Jun 2003 Location: Westminster, CO Posts: 3,071	The crack is in the housing. On the front side of it towards the cab. It is at about the fill plug level but on the other side of the fill plug. This must of happened when the original gears and posi unit exploded. What to do??? __________________ Alex 1971 Lil' Red 350 SBC 700R4

06-15-2005, 10:12 AM	#5
blazerparts No,I DON'T have Tourett's Join Date: Mar 2005 Location: Reno, NV Posts: 556	Maybe get a skid plate for the diff. Then occasionally when at Wal Mart parking lot, squeegie the accumulated drips out. __________________ '72 K5 CST 350/350 Daily Driver '69 GMC3500 Camper Special CST Flatbed 396/400 Upgraded to show truck '69 GMC 2500 L6292, 3spd beater

06-15-2005, 10:34 AM	#7
blazerparts No,I DON'T have Tourett's Join Date: Mar 2005 Location: Reno, NV Posts: 556	Can you weld a cast material? __________________ '72 K5 CST 350/350 Daily Driver '69 GMC3500 Camper Special CST Flatbed 396/400 Upgraded to show truck '69 GMC 2500 L6292, 3spd beater

06-15-2005, 10:50 AM	#8
ChevyDude Senior Member Join Date: Jun 2003 Location: Westminster, CO Posts: 3,071	Not sure??? Maybe JB weld glue is the way to go. The Permatex is still holding but probably won't last. Just seems like a shame to have to buy a whole new housing for such a small crack. I dunno??? __________________ Alex 1971 Lil' Red 350 SBC 700R4

06-15-2005, 12:14 PM	#9
68 Stepside huh? Join Date: May 2000 Location: Washington, Illinois Posts: 5,692	Welding cast is no easy feat. Even when you do a good job welding cast, I've seen it crack right next to the area that's been welded. Lincoln Electric has a nice page, all about welding cast. Here's the link: http://www.lincolnelectric.com/knowl...ronpreheat.asp Personally, I would try the jb weld. As long as you get the surface throughly cleaned, you should have no problem with it. Good luck __________________ Someday when I'm lonely, Wishing you weren't so far away, Then I will remember Things we said today. RIP El Jay

06-15-2005, 12:15 PM	#10
fastwillie 696969 ~Rest In Peace~ Join Date: May 2005 Location: CALIFORNIA NOR CAL Posts: 9,707	yes you can weld cast iron but its cost alot your best bet it to do a jb weld fix and paint over it __________________ is it fast ? it has a lighting bolt donut? B___H please, I can remove 90% of your so called "beauty" with a kleenex

06-15-2005, 12:36 PM	#11
71Dragtruck Registered User Join Date: Jun 2004 Location: Saskatchewan, Canada Posts: 1,368	To fix cast you either have to brase it ( not as strong ), or pre-heat it and DC weld it with nyerod, a nickel rod used for cast. The weld will be ugly it flows like crap, and you have to pound the weld down before it cools and cracks ( cast will shrink as it cools faster than the weld ). It has been done with regular rod and pre heat, not sure on that though. Last edited by 71Dragtruck; 06-15-2005 at 12:37 PM.

06-15-2005, 12:59 PM	#12
ChevyDude Senior Member Join Date: Jun 2003 Location: Westminster, CO Posts: 3,071	JB WELD is gonna be the ticket. I once fixed and 14' aluminum boat with pin holes in a hundred places with JB Weld. Worked great. __________________ Alex 1971 Lil' Red 350 SBC 700R4

06-15-2005, 01:05 PM	#13
70c10 67-72 Addict! Join Date: Feb 2002 Location: The TAX State! Posts: 7,857	Alex, maybe you should take it back to the shop that did the work and ask them how they would fix it. I guess they didn't notice it while having it apart. Maybe they will cut you a break and do it a little cheaper than normal if it's not that big of a deal. __________________ Jim 1970 C/10 Fleetside w/Ghost Flames Lowered 4.5" front and 4" rear (Raked) 355/350 Turbo w/shift kit 10" Redneck Performance Verter w/2500 stall Hooker Super Comps part#2808-1 Performer RPM Air-Gap 12 Bolt w/3:73 gears- Eaton Posi Comp Cams XE262 with 1.6 Crane Energizers, Road Demon 625 and Brodix IK 180 heads

06-15-2005, 01:07 PM	#14
71Dragtruck Registered User Join Date: Jun 2004 Location: Saskatchewan, Canada Posts: 1,368	Keep a close eye on it, it would be a shame if it cracked all the way and took out your new gears.

06-15-2005, 02:47 PM	#15
chickenwing Lovin' Life in Miss.! Join Date: Mar 2004 Location: Puckett, Mississippi Posts: 1,937	My first worry is if the crack will get worse. No experiance with diffs but Im pretty sure I'd be mad that the shop did not verify the housing was rebuildable. They knew you blew it up. Maybe the shop will swap it to another housing for you for the price of the housing. Any one that can comment on how hard/easy it is to spot cracks prior to rebuild? Are you supposed to look for cracks? Common ya gotta check, right? __________________ The truck... you hear that? No really, you did hear that?!!!

06-15-2005, 05:42 PM	#16
muddbugg72 Registered User Join Date: Sep 2003 Location: port allen louisiana Posts: 207	i have heard of drilling a small hole at each end of the crack to keep it from running then jb weld. i have a front diff doing the same thing and when i get ready to install it thats what im going to try. l



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06-15-2005, 05:56 PM	#17
chickenwing Lovin' Life in Miss.! Join Date: Mar 2004 Location: Puckett, Mississippi Posts: 1,937	I've been trained to do that for sheetmetal... __________________ The truck... you hear that? No really, you did hear that?!!!

06-15-2005, 09:10 PM	#18
cduster Registered User Join Date: Oct 2002 Location: S.W. Michigan Posts: 403	My suggestion was going to be to stop drill with about a 1/8th inch drill on both ends of the crack, grind a v-notch over the crack, wipe it down with a good cleaner/degreaser (even use some ether, it will work good) then J-B Weld and paint. This has worked for me before. Dan __________________ Good Judgment comes from experience. Most experience comes from bad judgment.

06-17-2005, 10:01 AM	#19
ChevyDude Senior Member Join Date: Jun 2003 Location: Westminster, CO Posts: 3,071	Well, The Permatex has stopped the leak. However, I am going to wire wheel the area clean and drill small "stop" or "control" holes at each end of the 1/2" crack. JB weld will fill and seal it. That's the best I can figure. Thanks Guys, You all rock!!! __________________ Alex 1971 Lil' Red 350 SBC 700R4

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