Author Topic: Main seal leak on 440 (1968 date code) replacement?  (Read 2182 times)

Offline DocMel

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Main seal leak on 440 (1968 date code) replacement?
« on: September 25, 2015 - 02:58:56 PM »
Gents. 

I have narrowed down an oil leak:  Its my main seal on my 440, manual tranny.   Bummer is I have only about 1000 miles on the newly rebuilt engine, but it is what it is....... I'd say I had about a half teaspoon in the inside bottom of my flywheel inspection cover after driving about 200 miles

I have changed out main seals on Chevys, Fords, but never on a 440  (The engine is date coded 1968 year if that makes a dif).   

Can the main seal be changed out by just removing oil pan?

Any hints, advice is appreciated




Offline cudabob496

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Re: Main seal leak on 440 (1968 date code) replacement?
« Reply #1 on: September 25, 2015 - 04:11:49 PM »
Ive seen a few discusions that say yes.
I've had the same leak for 15 years.
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline dfrazz

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Re: Main seal leak on 440 (1968 date code) replacement?
« Reply #2 on: September 25, 2015 - 05:57:09 PM »
I just did this a couple of weeks ago.  I have a 727 but I believe it is the same once you pull the pan you can access it. 

Offline cudabob496

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Re: Main seal leak on 440 (1968 date code) replacement?
« Reply #3 on: September 25, 2015 - 08:21:06 PM »
I just did this a couple of weeks ago.  I have a 727 but I believe it is the same once you pull the pan you can access it.

how easy was it? what product did you use? got a proceedure?
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline dfrazz

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Re: Main seal leak on 440 (1968 date code) replacement?
« Reply #4 on: September 25, 2015 - 08:54:16 PM »
how easy was it? what product did you use? got a proceedure?

I got my seal from Dave at Roseville, he has a good one that is not the cheap pipe cleaner.  Pretty straight forward - pull the pan and the seal, clean up all the old RTV, I used the black when I stalled the new seal, and then goop the crap out of the bottom when you put it back together.  The only tricky part is keeping the side parts up in while you are installing the bottom piece.  Just takes time and patience.

I added a windage tray since I had the pan off too.  Got that from Dave too.

Offline cudabob496

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Re: Main seal leak on 440 (1968 date code) replacement?
« Reply #5 on: September 26, 2015 - 01:45:50 AM »
I have a windage tray, will I have to pull that too?
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline dfrazz

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Re: Main seal leak on 440 (1968 date code) replacement?
« Reply #6 on: September 26, 2015 - 09:54:08 AM »
I have a windage tray, will I have to pull that too?

Yes, that will have to come out with the pan.

Offline cudabob496

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Re: Main seal leak on 440 (1968 date code) replacement?
« Reply #7 on: September 26, 2015 - 01:18:41 PM »
thanks
72 Cuda, owned 25 years. 496, with ported Stage VI heads, .625 in solid roller, 254/258 at .050, 3500 stall, 3.91 rear. 850 Holley DP, Reverse manual valve body.

1999 Trans Am, LS1, heads, cam, headers, stall, etc! Love to surprise the rice rockets with this one. They seem so confident, then it's "what the heck just happened?"

2011 Kawasaki Z1000

Offline Racer57

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Re: Main seal leak on 440 (1968 date code) replacement?
« Reply #8 on: September 26, 2015 - 10:50:40 PM »
My 383 rear main was leaking and I finally fixed it.  Read this thread........
http://www.cuda-challenger.com/cc/index.php?topic=107015.msg1050735#msg1050735

Offline DocMel

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Re: Main seal leak on 440 (1968 date code) replacement?
« Reply #9 on: September 27, 2015 - 10:11:04 AM »
Ill be going w/the Fast Fish seal.  Instructions look straight forward.  Ill get it in the next couple of weeks and will post installation, pics and results