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Rear Main Seal

This is a discussion on Rear Main Seal within the Technical / Maintenance forums, part of the General Discussion category; I have a 97 Suburban with a 350. I am convinced the rear main seal is leaking since I am ...

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    Rear Main Seal


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    I have a 97 Suburban with a 350. I am convinced the rear main seal is leaking since I am getting oil down the transmission bell housing.

    My "always lacking essential info repair" manual says that this seal can be replaced without pulling the tranny. It says to remove the brace rods, bell housing and oil pan.....then you can get to the seal.

    Is this correct..can you replace without pulling the tranny?

    Any tricks to make this easy?

    Craig

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    Can I help you? ksukats57's Avatar
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    Re: Rear Main Seal

    I would like to know this too. My mechanic thinks it the back of the intake where it meets the block, i say rear main


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    Registered User Barc's Avatar
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    Re: Rear Main Seal

    if oil is coming off the top of the outside of the bellhousing, it's not the rear main. It probably would be the intake, or the pressure sending unit. Is the oil coming out from the back of the oil pan and spreading all over your tranny pan? That would be your rear main. If it's coming out the front of the pan and covering the oil pan it's the front seal.

    Oh and you do have to pull the tranny to replace the rear main.
    Last edited by Barc; 04-01-2008 at 05:41 PM.
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    Re: Rear Main Seal





    whats it look like


    2006 Tahoe Z71

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    Registered User 96SLT350's Avatar
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    Re: Rear Main Seal

    I would say check the back of your manifold to make sure there isnt any oil leaking near the distrubutor and if its clean. Go ahead wit hthe rear main seal. get a 2 piece, makes it easier the next time you replace!

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    Re: Rear Main Seal

    its hard to see back there


    2006 Tahoe Z71

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    Re: Rear Main Seal

    The drip on your flywheel cover looks like tranny fluid.
    I don't think that's engine oil.
    If it was engine oil on the pan, if it wasen't coming from above that wouldn't be a rear main either. It would be the pan gasket or the u seal at the back of the pan. Rear mains usually leak really bad.

    But if you have a 2 piece you can take the last main cap off, and "push/roll them out and in"
    If you do have a 2 piece you should set the ends horizontal or somewhere close so the split isn't the same as the cap.

    See what color the drops are. If it is red at all like it looks in the pic's it's not the engine.


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    Re: Rear Main Seal

    Its oil. I know that. My tranny fluid is like new, red and sweet. I am positive its oil too cause the drops are brown and match whats on the dipstick when bled onto a paper towel.


    2006 Tahoe Z71

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    Registered User 96SLT350's Avatar
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    Re: Rear Main Seal

    Looks as if it is motor oil to me. I notice that your oil pan has oil resudue around the bolts. but mostly looks as though its comming from the flywheel side.. have a look at where the starter foes in... looks like oil splashed up there off the flexplate and dried up a bit.... and i bet you it could very well be a rear main seal. but you should still take a clean rag and reach down as far as you can behind your motor and see if there is any fresh sludge near the top of the trans and the manifold. If so. your manifold needs new gaskets/ Ac delco black RTV sealant on both ends.

    OH! check your Valve covers to make sure they are tight and not leaking.
    Last edited by 96SLT350; 04-01-2008 at 06:21 PM.

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    Re: Rear Main Seal

    Then as long as you don't have any oil above the oil pan, do the oil pan gasket.
    If you have a 2 piece rear main I would do that while you have the pan down, if you don't then it's up to you. I would take the flywheel cover off and see if it's the rear main or the u seal at the back of the pan.


    03 Silverado ECSB, Dmax, Allison, 3.73 G80
    96 Silverado ECSB, 350, 4L60E, 3.73's Powertrax Locker
    05 Cavalier
    74 Corvette Stingray, 350, 4 speed
    49 F-1, flathead 6, 4 speed, 2wd, unknown rear end. Old rust bucket.

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    Re: Rear Main Seal

    k im goin out now so ill b back in a sec


    2006 Tahoe Z71

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    Re: Rear Main Seal

    I honestly thought they quit using 2 piece rear mains in the 80's.
    But my Chilton's only shows a 2 piece, so while you have it apart have at it.


    03 Silverado ECSB, Dmax, Allison, 3.73 G80
    96 Silverado ECSB, 350, 4L60E, 3.73's Powertrax Locker
    05 Cavalier
    74 Corvette Stingray, 350, 4 speed
    49 F-1, flathead 6, 4 speed, 2wd, unknown rear end. Old rust bucket.

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    Re: Rear Main Seal

    can any 383 crankshaft work in one of these motors?

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    Re: Rear Main Seal

    Quote Originally Posted by kcb37
    I honestly thought they quit using 2 piece rear mains in the 80's.
    But my Chilton's only shows a 2 piece, so while you have it apart have at it.
    correct, 1986 was the transition year
    Last edited by dave89iroc; 04-01-2008 at 06:34 PM.
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    Re: Rear Main Seal

    My 88-98 Chiltons shows that it has a split rear main.
    My bad, didn't look hard enough. The 4.8 and 6.2 are split.
    The 4.3, 5.0, 5.7, and 6.5 are one piece rear mains.

    Take off your flywheel cover and look to see where it is leaking for sure, cause your tranny has to at least be moved back.


    03 Silverado ECSB, Dmax, Allison, 3.73 G80
    96 Silverado ECSB, 350, 4L60E, 3.73's Powertrax Locker
    05 Cavalier
    74 Corvette Stingray, 350, 4 speed
    49 F-1, flathead 6, 4 speed, 2wd, unknown rear end. Old rust bucket.

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    Registered User Barc's Avatar
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    Re: Rear Main Seal

    I have a 97 350 in the garage, it's a 2pc. I can't see the pics here at work.
    '79 K5
    35" BFG's
    lift
    rattle can black

    '86 Silverado C10 RCLB
    peeling paint
    and dents courtesy
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    Re: Rear Main Seal

    I just put a tranny in my truck. You will have to move the tranny back several inches. loosen the torque converter. Remove the flywheel then you will have access. I would consider this a several hour job. Something that would take a whole day to do.

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    Re: Rear Main Seal

    I am curious now, cause I want to know what does and doesn't have a 2 piece. I hope I have one. They are easy once you have the pan down. A 1 piece kinda sucks.


    03 Silverado ECSB, Dmax, Allison, 3.73 G80
    96 Silverado ECSB, 350, 4L60E, 3.73's Powertrax Locker
    05 Cavalier
    74 Corvette Stingray, 350, 4 speed
    49 F-1, flathead 6, 4 speed, 2wd, unknown rear end. Old rust bucket.

  19. #19
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    Re: Rear Main Seal

    just took a peek. its coming from the intake mani cause the top of the bellhousing is moist from oil and a rag shoved up kinda under the dizzy rendered a lot of gunk on the rag. some wet. so a rear main is ruled out and i dont think the VC's are leaking


    2006 Tahoe Z71

  20. #20
    Registered User 96SLT350's Avatar
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    Re: Rear Main Seal

    1.5 hours labour with basic hand tools and gaskets / ac delco sealant


    make sure to allow the intake manifold sealant cure for 12- 18 hours before starting up

 

 
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