Bad rear end leak - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Isaiah92260 · 08-29-2019, 08:41 PM

Hey fellas, I have a 1961 with a really bad rear differential leak.

I noticed that it has always leaked but when I drained it out to do a oil change. It started leaking really bad from where the drive shaft meet the differential, and I also believe the rear cover seal is also leaking.

It’s that normal after being such an old truck? What seals do I have to replace? Thank you

65 GMC · 08-29-2019, 10:19 PM

Quote:

Originally Posted by Isaiah92260

Hey fellas, I have a 1961 with a really bad rear differential leak.

I noticed that it has always leaked but when I drained it out to do a oil change. It started leaking really bad from where the drive shaft meet the differential, and I also believe the rear cover seal is also leaking.

It’s that normal after being such an old truck? What seals do I have to replace? Thank you

I just did the pinion seal, both axle seals and rear cover gasket on my 65 C10. Sounds like yours needs the same. I know the 65 doesn't have the same axle as a 61 but I would think it be a similar job.

Isaiah92260 · 08-31-2019, 12:05 PM

Quote:

Originally Posted by 65 GMC

I just did the pinion seal, both axle seals and rear cover gasket on my 65 C10. Sounds like yours needs the same. I know the 65 doesn't have the same axle as a 61 but I would think it be a similar job.

Oh okay, I believe they might be similar.
Was it a difficult job to complete? I’m trying to do research on how I could properly take out that seal

**Getter-Done** · 08-31-2019, 02:13 PM

Here's a video
https://www.youtube.com/watch?v=gWogUZ4lttU

.

**Clyde65** · 08-31-2019, 07:10 PM

61 will have an HO32/33 rear end, 63-66 have 12 bolts

Isaiah92260 · 09-01-2019, 05:43 PM

Quote:

Originally Posted by Getter-Done

Here's a video
https://www.youtube.com/watch?v=gWogUZ4lttU

.

Thank you it looks fairly simple! I’m going to get down to it soon after I find some quilty parts

Isaiah92260 · 09-01-2019, 05:46 PM

Has anyone happen to have installed and used the 3.38 ring and pinion gears from Classic parts.com?
I found that they have the rear end upgrade and I’m wondering if it makes much of an improvement?
I already have an issue with maxing our at 50 55ish mph and I figure I might as well change out there gearing since I need to do the seal as well

**Captainfab** · 09-01-2019, 11:46 PM

Setting up differential gears is not an easy or simple job. Going from 3.90 to 3.38 is not a huge jump but it should be a noticeable rpm drop.

Brad54 · 09-03-2019, 12:28 AM

I'd band-aid this one: replace the seals to get by, then start looking for a different rear end and replace it.
The optional rear for a '60-'62 was the Dana 44, which was the standard rear in leaf-sprung GMC trucks of the era.
If you find a GMC, you can have a shop cut the mounting pads off the HO in your Chevy and move them to the GMC Dana 44. It's not a big job for any competent restoration, fabricator or welding shop.
OR, you can start the hunt for an original coil-sprung Dana 44 from a '60-'62 Chevy truck. I have an original in my '61 Suburban, and I've found a second as a spare.
The Dana 44 is the longest-production rear end in history, and a version of it is still used in Jeeps and Ford SUVs.
This is important, because Posi units are readily available, as are gear sets from 2.70 to 6.00.
I have 3.42 Posi in my Suburban, with a 4spd OD manual trans, and it's awesome.

Isaiah92260 · 09-05-2019, 08:02 PM

Thank you guys for your input. Captain I’ve reading that your right there is a lot of work involved for the update gear, especially lying under the truck without a lift lol

Isaiah92260 · 09-07-2019, 05:22 PM

I got the job done. I was really easy using the right tools like a gasket remover. I still have to clean up the rear end. I also noticed that the rear pumpkin is leaking somewhere I think around one of the bolts or it could be the cover gasket itself but the leak is far less and slower compared the the pinion seal.
Thanks guys for your help

08-29-2019, 08:41 PM	#1
Isaiah92260 Registered User Join Date: Jul 2015 Location: Whittier, CA Posts: 851	Bad rear end leak Hey fellas, I have a 1961 with a really bad rear differential leak. I noticed that it has always leaked but when I drained it out to do a oil change. It started leaking really bad from where the drive shaft meet the differential, and I also believe the rear cover seal is also leaking. It’s that normal after being such an old truck? What seals do I have to replace? Thank you

08-31-2019, 02:13 PM	#4
Getter-Done Senior Member Join Date: Dec 2009 Location: TN. Posts: 7,701	Re: Bad rear end leak Here's a video https://www.youtube.com/watch?v=gWogUZ4lttU . __________________ ________________________________________________________________________________________ ____________________________________________ 84 Chevy K-20 63 Impala (my high school car) http://67-72chevytrucks.com/vboard/s...Crew Cab Build

08-31-2019, 07:10 PM	#5
Clyde65 1965 Chevy C10, 2005 4.8L/4l60 Join Date: Aug 2004 Location: DFW Texas Posts: 8,539	Re: Bad rear end leak 61 will have an HO32/33 rear end, 63-66 have 12 bolts __________________ Clyde65 Rebuild of Clyde http://67-72chevytrucks.com/vboard/s...84#post8338184 69 Aristocrat Lo Liner build http://67-72chevytrucks.com/vboard/s...84#post7561684 *support our troops!*

09-01-2019, 05:46 PM	#7
Isaiah92260 Registered User Join Date: Jul 2015 Location: Whittier, CA Posts: 851	Re: Bad rear end leak Has anyone happen to have installed and used the 3.38 ring and pinion gears from Classic parts.com? I found that they have the rear end upgrade and I’m wondering if it makes much of an improvement? I already have an issue with maxing our at 50 55ish mph and I figure I might as well change out there gearing since I need to do the seal as well

09-01-2019, 11:46 PM	#8
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,246	Re: Bad rear end leak Setting up differential gears is not an easy or simple job. Going from 3.90 to 3.38 is not a huge jump but it should be a noticeable rpm drop. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

09-03-2019, 12:28 AM	#9
Brad54 Registered User Join Date: Aug 2006 Location: Athens, Georgia Posts: 1,456	Re: Bad rear end leak I'd band-aid this one: replace the seals to get by, then start looking for a different rear end and replace it. The optional rear for a '60-'62 was the Dana 44, which was the standard rear in leaf-sprung GMC trucks of the era. If you find a GMC, you can have a shop cut the mounting pads off the HO in your Chevy and move them to the GMC Dana 44. It's not a big job for any competent restoration, fabricator or welding shop. OR, you can start the hunt for an original coil-sprung Dana 44 from a '60-'62 Chevy truck. I have an original in my '61 Suburban, and I've found a second as a spare. The Dana 44 is the longest-production rear end in history, and a version of it is still used in Jeeps and Ford SUVs. This is important, because Posi units are readily available, as are gear sets from 2.70 to 6.00. I have 3.42 Posi in my Suburban, with a 4spd OD manual trans, and it's awesome. __________________ '61 Suburban daily driver: off the road due to 180-pound 8-pt buck! '62 K-10 long-step project '61 C30 Camper, aka "Valdez" There's no cool like Old School Last edited by Brad54; 09-09-2019 at 12:35 PM.

09-05-2019, 08:02 PM	#10
Isaiah92260 Registered User Join Date: Jul 2015 Location: Whittier, CA Posts: 851	Re: Bad rear end leak Thank you guys for your input. Captain I’ve reading that your right there is a lot of work involved for the update gear, especially lying under the truck without a lift lol

09-07-2019, 05:22 PM	#11
Isaiah92260 Registered User Join Date: Jul 2015 Location: Whittier, CA Posts: 851	Re: Bad rear end leak I got the job done. I was really easy using the right tools like a gasket remover. I still have to clean up the rear end. I also noticed that the rear pumpkin is leaking somewhere I think around one of the bolts or it could be the cover gasket itself but the leak is far less and slower compared the the pinion seal. Thanks guys for your help Attached Images



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