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Thread: What's best gasket/sealant to ensure a leak free transmission pan?

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    wh23g3g's Avatar
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    Default What's best gasket/sealant to ensure a leak free transmission pan?

    A couple weeks ago I had the neutral safety switch and extension housing seal replaced the 46RE in my 99 R/T. I thought that was it since I had the fluid and filter changed about a year ago. It's not my daily driver but I do drive it once or twice a week until it fully gets to operating temperature to keep everything working. It seems that every time I park it and once it gets around time to go for a ride I always see some small drip from the transmission somewhere. This time it appears to be a leak around the front edge of the pan gasket. I've had the plastic Mopar gasket on there but I had the shop change it last time so it may just be a rubber gasket from the Auto parts store now. I ran my fingers from under the NSS all the way around the pan flange and it was dry up until the front of the pan. You can see somehow it got a spot on the exhaust down pipes, not sure why the picture turns sideways. That's also where there is a drop on my garage floor. It's not a big puddle or even really a puddle. But after all I've had done it shouldn't be leaking at all. One time I bought a Mopar transmission gasket that I believe was the cork blend but now all I find is the plastic one. Which is better for sealing? I replaced the pan with the Dorman with the drain plug when I got the truck about 4 years ago now because the flange was bent on the original one. Is there a better leak free pan or better gasket that I should be using? I was always told RTV or sealant isn't usually used on transmission pans but is there any that might help?







    IMG_2680.jpg
    Last edited by wh23g3g; 07-29-2019 at 12:05 AM. Reason: picture turned around

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    BIGROB's Avatar
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    Might just need to tighten the bolts more. That gasket doesn't looked to be compressed much.

    Project Maverick. I feel the need, the need for speed

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    Saying the pan had the same shape integrity that you came in with, these need to be tightened to about 8 ft pounds only. You should need no other sealant.

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    Mark's Avatar
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    ATP Kit's have the best gasket by far.
    1999 R/C Solar yellow

  5. #5

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    Quote Originally Posted by Mark View Post
    ATP Kit's have the best gasket by far.
    I like their "third hand" gasket allowing you to put up some bolts into the pan for easier cinching and alignment.

  6. #6

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    There are 3 kinds of gaskets for this. Rubber, fiber and cork. I like the rubber type mainly because they are reusable. Cork has been used for ages and is an effective gasket. Fiber gaskets are usually the cheapest.
    Any one of these can provide a suitable seal. The material is not your problem. A shop can muckle a seal no matter where it is. If things like pans get banged around, dropped, over torqued, incorrectly torqued, you can garner a leak. I can almost guarantee one or more of these things occurred to your pan.

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    I've heard the Mopar or Moroso reusable gaskets are great. That's what I'm going to get.

    -Justin

  8. #8

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    Quote Originally Posted by xjsc16x View Post
    I've heard the Mopar or Moroso reusable gaskets are great. That's what I'm going to get.

    -Justin
    They are. Check into if this gasket needs to be torqued differently inch pound wise.

  9. #9

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    Just some added info. I believe the gasket you're looking to get is a composite rubber/steel affair. I don't like the all rubber ones for pan gaskets unless they're real good. The pure rubber ones tend to deflect and bulge out thus creating possible leaks.
    The Mopar rubber gasket is quite good as it also is a metal/rubber composite. Otherwise a cork gasket is my preference here if a rubber composite is not used.

  10. #10

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    Try Fel-Pro also. They have quality transmission gaskets.

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    wh23g3g's Avatar
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    I think the shop used a parts store brand rubber gasket last time because the Wix kit I brought wasn't right. Well I see now it's leaking at the corner. I cleaned the underside and you can see the fluid collecting in the corner and dripping right on top of the crossover exhaust pipe. I washed it a day ago, cleaned the garage floor and now it's caused another small puddle. I actually talked to the transmission shop around here and they said if you use RTV it will won't leak. I even asked another shop and they said the same. I know the Chrysler replacement gasket is the plastic one. Is the Moroso one part# 93110? I see it doesn't have the cut out between the two front bolt holes like all the other ones. Does that matter? I see Mopar Performance offers a cork one for the 727, Is that a better choice?. I think I remember the 727 and the 46RE have the same pan gasket right?

  12. #12

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    Quote Originally Posted by wh23g3g View Post
    I think the shop used a parts store brand rubber gasket last time because the Wix kit I brought wasn't right. Well I see now it's leaking at the corner. I cleaned the underside and you can see the fluid collecting in the corner and dripping right on top of the crossover exhaust pipe. I washed it a day ago, cleaned the garage floor and now it's caused another small puddle. I actually talked to the transmission shop around here and they said if you use RTV it will won't leak. I even asked another shop and they said the same. I know the Chrysler replacement gasket is the plastic one. Is the Moroso one part# 93110? I see it doesn't have the cut out between the two front bolt holes like all the other ones. Does that matter? I see Mopar Performance offers a cork one for the 727, Is that a better choice?. I think I remember the 727 and the 46RE have the same pan gasket right?
    Can't answer the Moroso question. I have a friend with a Camaro and he said his Moroso is holding up fine. I have the Mopar one on now and it's holding. I didn't use rtv but I did skim coat the pan with some grease to hold the gasket on.
    I do believe the bolt pattern is the same on the 727 with the pan being a bit shallower than the 46re.
    I feel the best gaskets are the composite structured ones such as the Mopar and the Moroso. I prefer cork over the pure rubber type if not the composite type.

    Just be sure a shop guy didn't pucker your bolt holes on the pan by gorilla torquing. . If they are, either get a new pan ( I like the ones that drain) or de pucker them with a socket of the correct size.You may have a couple pan bolts that are stripped as I did. If so, they'll just keep turning with no bite. Mopar gasket is slated for 150" lbs. of torque which is a bit over 12 ft lbs.

    Don't fret if you have some stripped. Just go to your local hardware store and buy the 5/16" automotive type bolt that is about a quarter inch longer than stock and has the bolt shoulder built in so no need for a washer. Chase the holes with a 5/16 tap simply to clean them up. Because there are some good threads left in the hole at their tops where the old bolts never got to, the longer bolt will grab enough remaining good thread to tighten to the 150 inch pounds.
    Last edited by arro222; 09-06-2019 at 06:39 PM.

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    slammedR/T's Avatar
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    just get a factory reusable transmission pan gasket, you're welcome.
    This signature has been deleted thanks to photobucket!

  14. #14

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    Quote Originally Posted by slammedR/T View Post
    just get a factory reusable transmission pan gasket, you're welcome.
    He means this one. https://www.cascadetransmissionparts...pangasket.aspx. Torque to 100 inch pounds at first and finish up at 150 inch pounds using cross bolt tighten method.
    It's the one I'm using and it is holding.

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    wh23g3g's Avatar
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    I had a cork one I bought from a Chrysler dealer when I first got the truck about 4-5 years ago ans I don't remember it giving any problems. Lost if when I had to have it for the governor pressure sensor changed. For some reason I can't that part number anywhere, I guess it might have been replaced with the plastic gasket but I think they've been using it for awhile. It was indeed a Mopar part. Thought maybe it was the Mopar Performance one, but it was a traditional cork not the fiber. So I just ordered the Mahle cork w metal carrier for a couple dollars on Rockauto. Went ahead and bought another filter too. It's been hard keeping this transmission sealed from leaks. Got the engine all sealed and the transmission has been leaking from somewhere almost the whole time I've had the truck.

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    Quote Originally Posted by xjsc16x View Post
    i've heard the mopar or moroso reusable gaskets are great. That's what i'm going to get.

    -justin
    this !!!
    11.27 @ 118.23
    2017 NM Mopar Challenge Series Champion

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