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Author Topic: rearmain seal  (Read 1960 times)


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  • Posts: 14
rearmain seal
« on: January 15, 2012, 07:02:40 PM »
I think I need to have my rear main seal replaced. I bought it used with 52,000 miles on it last summer. I only took one trip. leaking massive oil. Seems kind of low miles to need a rear main seal replaced. Is this common, any thoughts/


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  • Posts: 589
Re: rearmain seal
« Reply #1 on: January 15, 2012, 07:10:03 PM »
it would be nice if you told us what kind of engine, etc.
2002 Fleetwood Fiesta 31H, 2001 F53 Ford chassis
2002 Toyota Tacoma Xtra Cab 2wd
2 cats:
Rusty-11 year old red mackerel tabby with white, male, 24#,  leash trained.
Penny-10 year old black and white DLH, 15#, female.
Home---Ocala, FL
Avatar: '58 VW bus, 350hp 327 Chevy, TH400 & '57 Pontiac rear end.


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  • Posts: 14
Re: rearmain seal
« Reply #2 on: January 15, 2012, 07:26:12 PM »
chevy 454


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  • Posts: 267
Re: rearmain seal
« Reply #3 on: January 15, 2012, 08:33:08 PM »
Make sure there is not something else causing the leak. I thought I had a bad rear seal once because my engine was leaking massive amounts of oil.  Turned out to be a cracked diaphragm in the oil pressure gauge sendign unit.  Crawl under there and see if you can pinpoint where the leak is.  You might luck out.
1992 24' Fleetwood Class "C" Jamboree Rallye
Ford E350 Chassis
Toad - 1969 Volkswagen Baja Bug
San Marcos, CA


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  • Posts: 2030
Re: rearmain seal
« Reply #4 on: January 15, 2012, 08:39:17 PM »
First thing you need to do is confirm where it is leaking from. Could be the rear main or it could be the oil pan, rear rocker covers, block plug, etc, etc. Get a dye kit from a parts store and verify the leak.
Donít know what year your 454 is but if it is a rear main they used 2 piece seals until the 90ís then a one piece. One needs the pan pulled, the other needs the trans pulled. If you do have to replace there are many things you need to follow specifically such as cleaning and install methods or you will learn on your 2nd or 3rd try. If the seal area is damaged you can get a special extended seal from the parts store to put the sealing area in another position. If the rear is bad I would also check PCV or whatever your engine is using to vent the crankcase. Usually the front main goes first is this case but again, you need to clean everything and verify exactly what is leaking. Iím going from memory on this but there is plenty of info on replacing seals etc. depending on what you find. Good luck and welcome to the forum.
2009 Tiffin Allegro Bus 43 QRP
Powerglide Chassis, 425 Cummins, Allison 6 Speed
2010 CRV - Blackhawk 2 - Air Force One
2002 Heritage Classic
Washington State


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  • Posts: 596
Re: rearmain seal
« Reply #5 on: January 15, 2012, 08:45:10 PM »
Look on the top back of the motor to make sure it is not the oil Pressure sending unit leaking down. Had that happen couple of times.
Terry & Kathy Weller
Direct Sales Jewelry
It goes where you are.


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  • Posts: 114
Re: rearmain seal
« Reply #6 on: January 18, 2012, 11:40:21 PM »
When I was in the business, we found that most "rear main seal " leaks disappeared when the valve cover gaskets were replaced,.  Just a thought . . . . . ........