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Trans. Pan Gasket Question #3085974
10/14/22 01:18 PM
10/14/22 01:18 PM
Joined: Jan 2003
Posts: 5,587
Detroit area
6PAX Offline OP
master
6PAX  Offline OP
master

Joined: Jan 2003
Posts: 5,587
Detroit area
I just put the pan back on my 727 using a new rubber gasket and also a thin coat of Ultra Black. I tightened the pan bolts to 150 in/lbs per the book and assumed all was good and started cleaning up. Went back to the trans. to pick up some tools and happen to look at the pan and the gasket was squirting out from the pan in two spots (both corners on passenger side). Is 150 in/lbs. too much for a rubber gasket? I know people are gonna say I should have used the Mopar hard gasket but the last time I used one of those it leaked too so I just used the rubber gasket since I already had it. I loosened all the bolts and the gasket receded back into place on it's own so should I just snug the bolts up till they are snug?

Re: Trans. Pan Gasket Question [Re: 6PAX] #3085987
10/14/22 01:48 PM
10/14/22 01:48 PM
Joined: Aug 2003
Posts: 43,007
Bend,OR USA
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Cab_Burge Offline
I Win
Cab_Burge  Offline
I Win
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Joined: Aug 2003
Posts: 43,007
Bend,OR USA
Have you check THAT pan for flatness? How about the bolt holes, are they flat or dimpled in? How about the bottom sealing ledge on the tranny? scope
Either one can and probably will make them seep or leak shruggy


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Trans. Pan Gasket Question [Re: Cab_Burge] #3085995
10/14/22 02:01 PM
10/14/22 02:01 PM
Joined: Jan 2004
Posts: 8,193
fredericksburg,va
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cudaman1969 Offline
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fredericksburg,va
When you say rubber is that the one that’s stiff with the ridges? I’ve started using that one with no sealer and it stays dry and tight. 150” pounds sounds tight.

Re: Trans. Pan Gasket Question [Re: 6PAX] #3086008
10/14/22 02:27 PM
10/14/22 02:27 PM
Joined: Mar 2011
Posts: 3,056
Michigan
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A727Tflite Offline
master
A727Tflite  Offline
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Joined: Mar 2011
Posts: 3,056
Michigan
Originally Posted by 6PAX
I just put the pan back on my 727 using a new rubber gasket and also a thin coat of Ultra Black. I tightened the pan bolts to 150 in/lbs per the book and assumed all was good and started cleaning up. Went back to the trans. to pick up some tools and happen to look at the pan and the gasket was squirting out from the pan in two spots (both corners on passenger side). Is 150 in/lbs. too much for a rubber gasket? I know people are gonna say I should have used the Mopar hard gasket but the last time I used one of those it leaked too so I just used the rubber gasket since I already had it. I loosened all the bolts and the gasket receded back into place on it's own so should I just snug the bolts up till they are snug?


The backbone Mopar gasket does not leak.

IF - you have an undamaged, flat pan flange, no damage to the case, etc. You can’t overtighten them either.

Adding silicone to a rubber gasket just lubes them up allowing them to squirt out. If your pan leaked with the Mopar gasket it’s going to leak with the others unless you slop a tube of RTV all over the place.

Re: Trans. Pan Gasket Question [Re: A727Tflite] #3086026
10/14/22 03:05 PM
10/14/22 03:05 PM
Joined: Dec 2005
Posts: 11,408
Fulton County, PA
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CMcAllister Offline
Mr. Helpful
CMcAllister  Offline
Mr. Helpful
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Joined: Dec 2005
Posts: 11,408
Fulton County, PA
Gasket or gasket maker. Not both. I prefer gasket. Specifically, the fiber style.Stamped steel pan has to be straight. 120 lbin. or so. No more than 150.

Last edited by CMcAllister; 10/14/22 03:12 PM.

If the results don't match the theory, change the theory.
Re: Trans. Pan Gasket Question [Re: 6PAX] #3086028
10/14/22 03:07 PM
10/14/22 03:07 PM
Joined: Jan 2010
Posts: 1,440
NW Chicago suburban area
Mopar Mitch Offline
pro stock
Mopar Mitch  Offline
pro stock

Joined: Jan 2010
Posts: 1,440
NW Chicago suburban area
Rule #1: Never install a rubber gasket with RTV silicone. Why? Because rubber is not compressible... it is deformable. So, IF you apply RTV silicone spread across a rubber gasket, its the same as spreading grease across it. the gasket will simply slide and want to split/deform very easily. You will never find a gasket manufacturer with directions to apply RTV silicone across a rubber gasket. Rubber gaskets are always best installed DRY without any wet chemical.

Rule #2: Check for flatness... both surfaces must be flat (stamped pans, etc tend to have distortion, especially at the bolt holes... replace or flatten as needed.

Rule #3: Clean all threadings... so to reduce and eliminate unwanted friction.

Rule #4: Tighten to manufacturer's specifications... avoid over-tightening.

Remember, again, that rubber is not compressible... its deformable and only by about about 30% of its thickness... squeezed any more than that and it'll split apart. (Cork-rubber, by comparison, can be compressed 50%... more forgiving to out-of-flatness and irregular surface imperfections.)

I 'm a former gasket engineer from a major leading company... and I wrote the instructions within their gasket sets.


Mopar Mitch "Road racers and autocrossers go in deeper and come out harder!"... and rain never stops us from having fun with our cars... in fact, it makes us better drivers! Check out MOPAR ACTION MAGAZINE, August 2006 issue for feature article and specs on my autocross T/A!
Re: Trans. Pan Gasket Question [Re: Mopar Mitch] #3086096
10/14/22 08:24 PM
10/14/22 08:24 PM
Joined: Mar 2006
Posts: 9,791
MI, usa
dvw Offline
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dvw  Offline
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Joined: Mar 2006
Posts: 9,791
MI, usa
Stock pan gets the factory style cork, dry. The 518 pan can use the reusable steel core rubber coated gasket, also dry.
Doug

Re: Trans. Pan Gasket Question [Re: 6PAX] #3086111
10/14/22 09:24 PM
10/14/22 09:24 PM
Joined: Dec 2016
Posts: 1,110
Usa
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A39Coronet Offline
super stock
A39Coronet  Offline
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Joined: Dec 2016
Posts: 1,110
Usa
Steel core moroso blue gaskets for valve covers and pan gaskets for me. No leaks and no gasket blowout. Need longer studs tho


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Re: Trans. Pan Gasket Question [Re: A39Coronet] #3086237
10/15/22 12:41 PM
10/15/22 12:41 PM
Joined: Jan 2003
Posts: 8,390
Highland, MI.
Sunroofcuda Offline
master
Sunroofcuda  Offline
master

Joined: Jan 2003
Posts: 8,390
Highland, MI.
Good stuff to know here - GREAT thread!


No Man With A Good Car Needs To Be Justified
Re: Trans. Pan Gasket Question [Re: Sunroofcuda] #3086286
10/15/22 02:48 PM
10/15/22 02:48 PM
Joined: Sep 2003
Posts: 19,239
north of coder
moparx Offline
"Butt Crack Bob"
moparx  Offline
"Butt Crack Bob"

Joined: Sep 2003
Posts: 19,239
north of coder
if you are using a cast aluminum pan, make sure your bolts are long enough to engage enough threads in the transmission case to prevent stripping the threads. [you know : "tighten them until they strip or break, then back them off 1/2 turn"! as i always say. biggrin]
or use studs, which i prefer when using a cast pan.
beer

Re: Trans. Pan Gasket Question [Re: moparx] #3086439
10/16/22 09:57 AM
10/16/22 09:57 AM
Joined: Jan 2003
Posts: 13,544
md
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mopars4ever Online content
I Live Here
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Joined: Jan 2003
Posts: 13,544
md
I just bought this gasket. Any feed back on this one? https://www.ebay.com/itm/115529800890







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