10 Bolt Eaton Problem - The 1947 - Present Chevrolet & GMC Truck Message Board Network

71400lb · 07-13-2004, 08:53 AM

...I posted this to the wrong board earlier(Suburban Board), sorry.

I have a 1971 Cheyenne 3/4 Ton, originally came with a 350/350. I believe the big ten bolt is the Eaton that everyone has trouble identifying. Looking underneath, from the back of the truck, you see the round pumpkin...the ten bolts are all equally spaced from eachother except at 9 o'clock and at 3 o'clock where two bolts are only like an inch apart instead of three inches.

Okay, so if I indeed have this Eaton, my problem is that the pumpkin is leaking. It leaks about one tear drop per day. Is this crucial, or can I wait a while to fix it?

Where can I find a gasket for this rear end? Should I use cork, rubber, combination of cork and sealant?

Also, the guy I bought it from swears it's a 3.73 gear in the back, but from reading posts on this board, that can't be stock, it would've been an aftermarket swap right?

Sorry so long,
Thanks
Rick

1971 Chevy Cheyenne 3/4 Ton Long bed
400/400 4 bbl quadrajet
3 spd on column
3.73 open diff
dual exhausts
towing package

**JIMs70GMC** · 07-13-2004, 09:02 AM

No gasket that I know of. Mine leaks a little also. use some rtv. As far as I know the tallest gears were 4.10s w/ 3.90s available aftermarket. Typically the gears were either 4.10 or 4.56s.

It is the corperate axle refered to as the eaton or RPO # H052 or H072.

Fred T · 07-13-2004, 10:45 AM

Don't know just exactly what's leaking from your description. Rear cover, pumpkin to housing or the pinion seal? The gaskets and seal are available from a local parts store. They do need the HO52 id to get the right gaskets. Usually the pinion seal is what leaks, it's just aft of the u-joint. Requires removal of the trunnion to replace, and if the shaft of the trunion hs a groove in it you also need a redi-sleeve.

On the 3/4 ton auto trucks, the 4.10 gear was stock. 3.73s were available as an option on the Blazer, I've been told.

Robert1970C20rstbukt · 07-13-2004, 03:04 PM

I had the same problem with mine, except that it's a corporate rear, not an eaton. My Dad bought some cork/rubber gasket material from autozone and cut it out and I put the rear cover on and filled it with grease and it hasn't leaked for about a week now.

**COBALT** · 07-13-2004, 05:56 PM

HO52/72 corporate axles are for 3/4 ton and 1 ton respectfully, and they are a pain in the butt to find parts for. They have an Eaton carrier, so that's why people call them Eaton Axles, which isn't technically correct.

Here's what I found out from Randy's Ring & Pinion when I asked about gaskets. Don't bother. They'll warp and leak even if you're lucky enough to find one. Use Silicone II Window/Door sealer (the black stuff). It's at Home Depot, Lowes, or any other home store in the blue white and gold tube. Works great, and stays relatively elastic so it will last for a long time.

Vince M · 07-13-2004, 09:36 PM

I got a gasket at AutoZone for mine and told them it was the HO72. No problems with the gasket at all.
One thing that is different on the Eaton is that the cover bolts go through the case and are exposed to oil below the oil level. When reinstalling the cover bolts use a Permatex non hardening gasket sealer on the threads. This will seal them. The axle bolts are the same. They are also exposed to oil as the holes go through the case. Same thing,seal them with the gasket sealer.
The best sealer I have used if you can't find a gasket is Permatex Ultra Black. Somebody above mentioned the gear ratios and thay are correct. No 3.73's are available for the Eaton.

The corporate 14 bolt solves much of the above problems. The bolts are blind holes all around so no leaks. The ratios for the 14 bolt are much wider and more available (read cheaper).

Oh yeah..forgot to mention that the bolts that hold the third member in are also exposed to oil. You might want to pull them out one at a time and seal them also.

Robert1970C20rstbukt · 07-13-2004, 10:22 PM

When I put the rear cover on mine I used yellow 3M weatherstrip/gasket adhesive and that stuff works great.

1969 GMC · 07-13-2004, 11:06 PM

On the H052 that I bought, the original diff cover gasket is still there and working great. No leaks except from the axle breather. When I popped the cover off to check if there was indeed a No-Spin inside, there was still a bunch of fresh looking gear oil and a nice rustfree gearset.

07-13-2004, 08:53 AM	#1
71400lb 71400lb Join Date: Jun 2004 Location: Charlotte NC Posts: 74	10 Bolt Eaton Problem ...I posted this to the wrong board earlier(Suburban Board), sorry. I have a 1971 Cheyenne 3/4 Ton, originally came with a 350/350. I believe the big ten bolt is the Eaton that everyone has trouble identifying. Looking underneath, from the back of the truck, you see the round pumpkin...the ten bolts are all equally spaced from eachother except at 9 o'clock and at 3 o'clock where two bolts are only like an inch apart instead of three inches. Okay, so if I indeed have this Eaton, my problem is that the pumpkin is leaking. It leaks about one tear drop per day. Is this crucial, or can I wait a while to fix it? Where can I find a gasket for this rear end? Should I use cork, rubber, combination of cork and sealant? Also, the guy I bought it from swears it's a 3.73 gear in the back, but from reading posts on this board, that can't be stock, it would've been an aftermarket swap right? Sorry so long, Thanks Rick 1971 Chevy Cheyenne 3/4 Ton Long bed 400/400 4 bbl quadrajet 3 spd on column 3.73 open diff dual exhausts towing package

07-13-2004, 09:02 AM	#2
JIMs70GMC user # 2756 Join Date: Jun 2001 Location: Chesapeake, Virginia Posts: 4,612	No gasket that I know of. Mine leaks a little also. use some rtv. As far as I know the tallest gears were 4.10s w/ 3.90s available aftermarket. Typically the gears were either 4.10 or 4.56s. It is the corperate axle refered to as the eaton or RPO # H052 or H072. __________________ 1970 K25, 8' stepside bed 350/465/205 44 up front, 60 in the rear 4.10s rolling on 33" Dunlop MTs 1986 K5, 350/465/208 Dana 60/14 bolt from a cucv 36" Super Swampers TSL/SX 1983 K20 w/ CUCV axles, 350/700R4/208 sitting on 37" Goodyears 1986 M1031 6.2 diesel, TH400/NP205 locker in the rear and a LS in the front, all stock for now..... 1986 K30, 350/400/205 dana 60 and 14 bolt. I kept the drivetrain. Body/bad and chassis are gone. 1981 K30, 350/465/205 dana 60 and dually 14 bolt. Has a G80, and a flat bed. Going to replace the flat bed. 1985 K20, 350/400/208 10 bolt and SF 14 bolt. I wonder where I can find some 1 tons. Hmmmmm

07-13-2004, 10:45 AM	#3
Fred T Cantankerous Geezer Join Date: Aug 2002 Location: Bel Aire, KS Posts: 6,264	Don't know just exactly what's leaking from your description. Rear cover, pumpkin to housing or the pinion seal? The gaskets and seal are available from a local parts store. They do need the HO52 id to get the right gaskets. Usually the pinion seal is what leaks, it's just aft of the u-joint. Requires removal of the trunnion to replace, and if the shaft of the trunion hs a groove in it you also need a redi-sleeve. On the 3/4 ton auto trucks, the 4.10 gear was stock. 3.73s were available as an option on the Blazer, I've been told. __________________ Fred There is no such thing as too much cam...just not enough engine.

07-13-2004, 03:04 PM	#4
Robert1970C20rstbukt Registered User Join Date: Jun 2004 Location: Beeville, Texas Posts: 1,943	I had the same problem with mine, except that it's a corporate rear, not an eaton. My Dad bought some cork/rubber gasket material from autozone and cut it out and I put the rear cover on and filled it with grease and it hasn't leaked for about a week now. __________________ RJD 1984 Chevrolet C30 welding truck 454/SM465 1977 GMC C15 pickup 350/TH350 1970 Chevrolet C20 pickup 350/TH400 1970 Chevrolet K20 Suburban 454/TH350 1969 GMC 8500 478M V6/5 spd winch truck

07-13-2004, 05:56 PM	#5
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	HO52/72 corporate axles are for 3/4 ton and 1 ton respectfully, and they are a pain in the butt to find parts for. They have an Eaton carrier, so that's why people call them Eaton Axles, which isn't technically correct. Here's what I found out from Randy's Ring & Pinion when I asked about gaskets. Don't bother. They'll warp and leak even if you're lucky enough to find one. Use Silicone II Window/Door sealer (the black stuff). It's at Home Depot, Lowes, or any other home store in the blue white and gold tube. Works great, and stays relatively elastic so it will last for a long time. __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.

07-13-2004, 09:36 PM	#6
Vince M Senior Member Join Date: Apr 2000 Location: Orlando, FL Posts: 1,076	I got a gasket at AutoZone for mine and told them it was the HO72. No problems with the gasket at all. One thing that is different on the Eaton is that the cover bolts go through the case and are exposed to oil below the oil level. When reinstalling the cover bolts use a Permatex non hardening gasket sealer on the threads. This will seal them. The axle bolts are the same. They are also exposed to oil as the holes go through the case. Same thing,seal them with the gasket sealer. The best sealer I have used if you can't find a gasket is Permatex Ultra Black. Somebody above mentioned the gear ratios and thay are correct. No 3.73's are available for the Eaton. The corporate 14 bolt solves much of the above problems. The bolts are blind holes all around so no leaks. The ratios for the 14 bolt are much wider and more available (read cheaper). Oh yeah..forgot to mention that the bolts that hold the third member in are also exposed to oil. You might want to pull them out one at a time and seal them also. __________________ ............................................................ 68 Chevy CST SWB w/LS1, carb & 700r4. Golden Anniversary clone with a few improvements.

07-13-2004, 10:22 PM	#7
Robert1970C20rstbukt Registered User Join Date: Jun 2004 Location: Beeville, Texas Posts: 1,943	When I put the rear cover on mine I used yellow 3M weatherstrip/gasket adhesive and that stuff works great. __________________ RJD 1984 Chevrolet C30 welding truck 454/SM465 1977 GMC C15 pickup 350/TH350 1970 Chevrolet C20 pickup 350/TH400 1970 Chevrolet K20 Suburban 454/TH350 1969 GMC 8500 478M V6/5 spd winch truck

07-13-2004, 11:06 PM	#8
1969 GMC Registered User Join Date: Feb 2003 Location: The Rubber City Posts: 5,498	On the H052 that I bought, the original diff cover gasket is still there and working great. No leaks except from the axle breather. When I popped the cover off to check if there was indeed a No-Spin inside, there was still a bunch of fresh looking gear oil and a nice rustfree gearset. __________________ 1969 GMC K2500 1996 Honda Accord 2007 Kawasaki KLR 650



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