Author Topic: How to tell? 1 or 2 pc rear main seal?  (Read 45230 times)

Offline Senck243

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How to tell? 1 or 2 pc rear main seal?
« Reply #15 on: December 02, 2012, 05:22:59 PM »
It is definitely a two piece seal


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Offline thirsty

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Re: How to tell? 1 or 2 pc rear main seal?
« Reply #16 on: December 02, 2012, 05:48:57 PM »
How did you determine that it is a two piece for sure?
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Offline VileZambonie

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Re: How to tell? 1 or 2 pc rear main seal?
« Reply #17 on: December 02, 2012, 08:13:50 PM »
There's some conflicting info here:

Small chevy 350 blocks will have a drivers side dipstick up to 1980. 1980 was when all of the small blocks went to passenger side dipstick. You will find one piece rear main seals were phased in in 1986. So it's true one piece rear main seal blocks will have a passenger side dipstick however so will two piece blocks so don't use that as a guide. You can tell by looking at the flexplate. If it's a counterweighted 350 it will be a one piece. The oil pans are different as well 55-79, 80-85, 86-99 and there are variances within those years too.
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Offline thirsty

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Re: How to tell? 1 or 2 pc rear main seal?
« Reply #18 on: December 02, 2012, 08:18:58 PM »
There's some conflicting info here:
Was I right on the size of the flange on the crankshaft or is that conflicting also Vile?
Real trucks are built, not bought Build thread

Give me a long enough lever and a place to stand, and I shall move the earth or break this bolt...Whatever, just hold my beer!

Offline VileZambonie

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Re: How to tell? 1 or 2 pc rear main seal?
« Reply #19 on: December 02, 2012, 10:04:40 PM »
The two piece has a counterweight on the end of the crankshaft, the one piece does not and is a perfect circle.

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,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10