Would a billet aluminum transmission pan be worth getting?

Engine, Transmission & Driveline

What sort of transmission pan do you use?

  1. Original steel

    60.0%
  2. Replacement OEM steel

    0 vote(s)
    0.0%
  3. stamped steel with drainage plug

    8.0%
  4. deep, higher volume stamped steel

    16.0%
  5. MACHINED steel, standard or enhanced volume

    0 vote(s)
    0.0%
  6. cast aluminum

    8.0%
  7. billet aluminum

    8.0%
  8. FORGED aluminum

    0 vote(s)
    0.0%
  9. OTHER

    0 vote(s)
    0.0%
  1. Gerald Morris

    Gerald Morris Senior Member

    Messages:
    1,151
    Likes Received:
    258
    Joined:
    Mar 9, 2016
    Location:
    Tucson
    Greetings to All Wise Moparians here!

    After nigh 3 years of driving the best transmission I've ever owned, the familiar, putrid fly of a leaking transmission pan interface has polluted the ATF. This leak first drew attention this past spring, meriting then a pint of Type F as I prefer to run in my 727s. This sufficed for about 2 months, with the shortage of fluid causing the behavior I've come to know and loathe from driving leaky old automatic trannies for 42+ years. After replacing the second pint in early June, I've consistently had to top up over intervals from two to one weeks, as the record hot summer enabled the 2nd Law of Thermodynamics to spike the local entropic gradients in corresponding record breaking slopes!

    I can take pictures if necessary of the stalagmite like drip deposits formed around or near some of the pan mounting bolts, clearly showing how ATF has seeped around the bolts, through the holes, leaving flexible polymer traces behind. The young sexagenarian who installed my after market, stamped steel pan with its commendable drain plug used copious quantities of black RTV in addition to whatever gasket he chose for the purpose. Before this spring, his work had no discernible flaw at all.

    Which brings me to consider which course to pursue to remedy a potentially expensive problem before it becomes such. I've already purchased a good Moroso (Perm-align 93110) silicone-rubber and steel sandwich re-usable gasket to free me from the necessity of waiting 24 hours after bolting the pan on before adding fluid and driving. This gasket appears to have numerous virtues making it well worth its price IFF it suffices to stop ATF leaking.

    I pray it will, and that the following paragraphs become pure academic grist for the brain-mills.

    IF the Moroso Perm-align fails to satisfactorily arrest leaking at the pan-transmission body interface as now equipped with that stamped steel pan, would it be worth my while and money to purchase a high grade aluminum pan which won't be apt to expand or contract at rates different from the aluminum transmission body of the Torqueflite 8?

    I ponder this little mechanics/thermodynamics problem after having survived driving every day of the hottest summer I have been so accursed to live through in my near 6 decades incarnate, particularly with those RTV/ATF stalagmites hanging from my transmission pan still vivid in my occipital lobes. The seal has incontrovertibly failed after having served well the previous two summers, the first being one of grueling city driving over much of a 6 hour shift in heat only marginally less than this years'. WHY?

    I will get a decent IR thermometer with which to read temperatures on the transmission and the radiator in particular, as well as the rest of the engine for good measure. An inordinate hot spot or a few dozen might account for such peculiarity, and if so, then the cure for such might stop the leaking.... or NOT.

    I suspect NOT.

    Having read some postings on this Forum, I see some satisfaction with the high grade aluminum pans. This inclines me toward making such an investment for my own needs, but ONLY after a REASONABLE exploration of other probable causes of renewed leaking at this interface after 3 summers. As always, I humbly seek the wisdom of each of you my Senior Moparians and others in this matter.
     
  2. oldkimmer

    oldkimmer Member

    Messages:
    140
    Likes Received:
    17
    Joined:
    Oct 30, 2019
    Location:
    Kindersley Saskatchewan Canada
    Have u checked the dipstick tube o ring and the manual shaft seals? They run down on to the pan and makes it appear to be leaking. Alum pans are great. They have a nice flat rail for the gasket to seal. Kim
     
  3. Gerald Morris

    Gerald Morris Senior Member

    Messages:
    1,151
    Likes Received:
    258
    Joined:
    Mar 9, 2016
    Location:
    Tucson
    I looked at the dipstick tube. NO stalagmites of ATF and RTV hanging from around it. Its oozing/dripping from that pan interface. I looked at the neutral safety switch also. I'll check the shifting linkage also with rigor in a few weeks. I('m not crawling back under that car until the summer breaks for good around here, unless there is some real emergency.

    I'm strongly inclined to get a GOOD aluminum pan at this point. I want this transmission to work for several decades to come, and with care, it will. This one really is the best driving tranny I've ever had in 43 years.
     
  4. FURYGT

    FURYGT Senior Member

    Messages:
    2,798
    Likes Received:
    1215
    Joined:
    Mar 11, 2017
    Location:
    Iron Station, NC
    A cast aluminum pan with fins or some other type of heat reducing quality can be beneficial in keeping a good seal & reducing fluid temperature. An extra capacity pan can also be beneficial but I understand that with some of the deep pans that you need or should also drop down the filter, however this is not an area that I have a lot of expertise in.
     
  5. 3175375

    3175375 Senior Member FCBO Gold Member

    Messages:
    1,148
    Likes Received:
    1111
    Joined:
    May 16, 2018
    Location:
    Centerville, South Dakota
    I think that @FURYGT is spot on.
    Different Thermal expansion / contraction rates of the steel pan and aluminum case may be causing the leak.
     
    • Agree Agree x 1
  6. CBODY67

    CBODY67 Old Man with a Hat

    Messages:
    5,354
    Likes Received:
    1224
    Joined:
    Mar 27, 2011
    To be sure, an aluminum pan of any type will have a machined surface for the gasket area, which should be a better deal. BUT, I also suspect that "the drip", especially around the attaching bolts, might be MORE from the wicking action of the fluid THROUGH the gasket itself. Especially if it's a rubber-cork gasket, which is known for such things, especially in the older valve cover gaskets (according to my machine shop operative).

    How that subject came up. Our Mopar club was having a little show at an area McDonalds back in the later 1980s. Back when valve cover gaskets seemed to always "leak". A friend was cussing the brand of oil he was using (a name brand) as he'd been having trouble getting his valve covers to seal properly. I'd been using the same brand of oil with no problems in that area. My friend then mentioned that he went to a more generic brand and the leaks stopped.

    He recounted how he'd put new gaskets on, flattened the gasket surfaces around the bolt holes, which was normal practice back then. To no improvement.

    When I mentioned that to my machine shop operative, he laughed and said it was the type of gasket, most probably. That once the oil started wicking through the dried-out cork, the only option was to replace the gasket with enough tightness to compress the cork, even with the then-newer rubber-cork types.

    Suddenly, all of the issues which I'd seen with valve cover gasket seals were explained. How that once that original engine paint on the valve covers/block aged and cracked after "a time", then valve cover leaks happened. Such that even with a good, careful install, they needed replacement every so many years/miles. So some just let them seep, usually, but if the seeps "hit the ground", then they'd get some new gaskets, cycle repeat.

    My machine shop operative asked what brand of oil my friend was using. I told him. Then the brand of oil which didn't leak. He laughed. What you WANT is the oil which causes the seeps, as it's light enough to be into places where the other oil doesn't get. Smaller molecules, a bit lighter viscosity, etc.

    My personal insurance against valve cover sseps is to put a thin coat of hi-heat black silicone sealer on the gasket, ANY gasket for that matter, a day or so before it's installed. This seals the gasket from any wicking action which might happen later on. PLUS it makes the gasket clean-off much quicker and easier! Remembering how hard it was to get the dried yellow gasket-retainer adhesive off of steel valve cover gaskets, in times past!! And, being the color it is, it's "in the shadows". This method has worked well for me over the past decades and has eliminated valve cover gasket changes as a part of my vehicles' general maintenance operations. Including on some Brand-X engines generally known for such things. Just smear a thin layer on with the finger of your choice. I always did it without finger protection, your option. It's easy to remove from the skin, usually. The high-heat black is generally a bit more viscous than the normal black, so that is preferred.

    If you desire a transmission pan other than the stock stamped steel version, your judgment call on that. For general principles, I'm wondering if it might be best to get a new trans pan anyway? In which case an aluminum pan should have the best/flattest sealing surface. Plus get a pan wiht an installed drain plug, just so it'll have one.

    Either way, I highly recommend coating the gasket as I have outlined for best results. At the very least, it makes clean-up/clean-off much easier should the gasket need to be removed for any reason.

    Just my experiences,
    CBODY67
     
    • Thanks! Thanks! x 1
  7. twostick

    twostick Senior Member

    Messages:
    2,221
    Likes Received:
    971
    Joined:
    Dec 13, 2012
    Location:
    Beautiful Downtown Roebuck Ont.
    Set your pan flange down on a flat surface. If it sits square with no gaps, reinstall it with a good gasket and replace the dipstick tube Oring with a correct one. If the one currently in there is not flat on the OD, that's your leak. If it is a correct flat one, chances are it's cooked brittle and needs a new one.

    A pint in 2 months is a very small leak and can easily weep around that oring and wick along the pan gasket.

    If I know the pan rail isn't bent and all the bolts are tight with a good gasket, 97% chance it's the tube, 3% selector shaft seal.

    Kevin
     
    • Agree Agree x 1
  8. BIGBARNEYCARS

    BIGBARNEYCARS Senior Member FCBO Gold Member

    Messages:
    4,036
    Likes Received:
    2644
    Joined:
    Dec 10, 2012
    Location:
    SHADOW OF MOTHER'S PROVING GROUNDZ
    I went nutz with an aluminum transmission pan but it didn't leak lol. I think I bought it from Summit, can't remember. The initial issue waz that it started life as a deep pan. I COULD NOT FIND A SHALLOW ALUMINUM PAN AND THAT DEEP PAN MOUNTED WAS LOWER THEN THE CENTER LINK, NOT GOOD FOR A STREET CAR! I took it to my Machinist and had him "carve out" 1 1/2"s horizontally from the middle of that pan. Then took it to a guy I know that made a very good living repairing aluminum boats and had him reattach upper and lower halves running the weld 360* inside and outside then one last trip back to the machinist for a last run to make curtain the top edge was still flat from all the wending(and it needed that 2nd machining last step) The gasket I use on everything I own comes from "REAL GASKET" in Tennessee, and if you want the best gasket on the planet, Pull them up on your computer and research them. It's about 1/8" thick and solid silicone. company has made the owners comfortably wealthy supplying the airplane industry with their gaskets. That iz high praise and well deserved. If you go that route follow their recommendations on mounting it "dry" and for torquing to 16 inch pounds. On yeah, They make basically the same gasket for the RB rocker covers too, Jer
     
    • Thanks! Thanks! x 1
  9. CBODY67

    CBODY67 Old Man with a Hat

    Messages:
    5,354
    Likes Received:
    1224
    Joined:
    Mar 27, 2011
    Reckon they were the source for the solid, orange silicone valve cover OEM Chrysler 440 valve cover gaskets for some police applications in the 1980s?

    Just curious,
    CBODY67
     
  10. 413

    413 Well-Known Member

    Messages:
    680
    Likes Received:
    229
    Joined:
    Jan 28, 2019
    Location:
    NW USA
    To answer the question, no a billet trans pan is not worth getting. Not to stop leaks anyway.

    There is no problem with a steel pan and aluminum transmission. The car manufactures made millions of them. They made it through warranty and beyond without leaking. The steel and aluminum doesn’t cause a leak in itself. There are many places a 727 can leak above the pan. The fluid always runs down hill and appears on the bolt heads. ATF is thin and runs down when hot and you won’t really notice the leak point.

    You have 7 common leak,points on a 66 and up torqueflight:
    two cooling lines and fittings
    shift seal
    neutral safety switch
    2nd gear band adjuster
    low band pivot shaft
    dipstick tube

    Last thing when it seeps fluid don’t overtighen the bolts and warp the pan. It needs a new gasket. Just like valve covers.

    A leak free trans does not come to the person who spends the most money or gets all the “trick of the day” parts.
     
    Last edited: Aug 30, 2020
    • Like Like x 2
    • Agree Agree x 2
  11. CBODY67

    CBODY67 Old Man with a Hat

    Messages:
    5,354
    Likes Received:
    1224
    Joined:
    Mar 27, 2011
    One thing about the dipstick tube o-ring . . . be SURE to get an o-ring that is "oil rated". They all look the same, but those not designed for oil sealing will usually leak after about 2 weeks of normal vehicld use, from my experiences at the dealership.

    One day, a tech came in wanting a new o-ring for a THM350. Seems he'd replaced it two weeks prior and now it was leaking again. I found a GM number for it, which we had in stock, which he also gladly took. End of problem. He noted that one of the other guys had been giving him o-rings from our generic assortment of o-rings.

    In this case, although not specifically mentioned, I suspect the OP had used spray brake cleaner to determine the leak/seep was below the parked fluid level in the trans, but that fluid level could also include leaks/seeps from a few of the items listed above.

    From my experiences,
    CBODY67
     
  12. Gerald Morris

    Gerald Morris Senior Member

    Messages:
    1,151
    Likes Received:
    258
    Joined:
    Mar 9, 2016
    Location:
    Tucson

    I suspect wicking as a major possible factor here. My current stamped steel pan has a nice drain plug, with several magnets deployed around it to catch any steel. (I pray this remains minimal of course, but whatever there is, I want it CAUGHT!) This has occurred to me, especially SEEING the way the fluid oozes out. I'm NOT enamored of spending $ on a new pan for the hell of it, but if that's what's needed, then its the cheapest and best course.

    I suppose the best course to pursue with this matter will be to replace the old gasket, carefully removing all the black RTV stuck to it. Since the silicone-rubber and steel sandwich gasket from Moroso purports to be non-porous and contra-indicates using RTV in their instructions, I will commence following them.

    IFF this arrests leaking, JOY!

    If otherwise, I will likely opt for a cast aluminum pan, with drain plug if possible, or a billet aluminum pan if casting precludes putting a drain plug in. (It shouldn't but we will see what's on the store shelves...) This will eliminate any bi-metallic expansion discrepancy.

    If leaking remains after this, I will overcoat the gasket, voiding the warranty on such, but at this point, I want my transmission sealed more than anything.

    I noted your approach in earlier threads, so this likelihood has been anticipated, but I already bought the gasket so.....

    As always, THANKS for the good thoughts/advice.

    Gerald
     
    • Thanks! Thanks! x 1
  13. Gerald Morris

    Gerald Morris Senior Member

    Messages:
    1,151
    Likes Received:
    258
    Joined:
    Mar 9, 2016
    Location:
    Tucson
    If I replace the dipstick tube O-ring, be sure, I WILL get one rated to stop hot mineral oil! The NSS also might warrant attention, but after seeing the pan, I figure First Things First.
     
    • Thanks! Thanks! x 1
  14. Gerald Morris

    Gerald Morris Senior Member

    Messages:
    1,151
    Likes Received:
    258
    Joined:
    Mar 9, 2016
    Location:
    Tucson
    Truer words have not been written! Having replaced gaskets on sundry automatic transmissions over the decades, I retain all the leak points mentioned in mind. I also never overtighten pan bolts, or any others, especially in old cast aluminum. I have ONE bolt hole which might need tapping for the next larger size (3/8"x16 I think) which I deem preferable to a heli-coil insert down in those relatively thin walls. First, I will need to inspect the work of the shop I hired to build this tranny 3 yrs ago.

    For leak-chasing, I plan to wash the surface with carbon-tetrachloride or whichever modern, "green-safe-etc..." brake cleaning fluid comes most readily obtainable. I can park Mathilda for 24 hrs after such a wash, then see what shows. The neutral safety switch is most suspect, given its age. If I see any red there, I plan to replace that.

    The monsoon showers FINALLY have broken the inversion layer over this big caldera valley containing Tucson, DEO GRATIAS! Maybe, by Equinox, it will cool down enough here to make for PLEASANT temperatures for wrenching! I'm NOT overjoyed with dropping a couple Ben Franklins on an aluminum pan for aesthetic reasons, and admit the coefficient of linear thermal expansion for aluminum at 1.6 x 10^-6 is close to steel at 1.2x10^-6, but as has been observed, it takes little gap for those mineral oil molecules to get through!

    As always, I appreciate your thoughts on this matter!
     
    Last edited: Aug 30, 2020
  15. BIGBARNEYCARS

    BIGBARNEYCARS Senior Member FCBO Gold Member

    Messages:
    4,036
    Likes Received:
    2644
    Joined:
    Dec 10, 2012
    Location:
    SHADOW OF MOTHER'S PROVING GROUNDZ
    Could be, not sure. The gaskets I'm talking about are some where between off red and ? but man do they do the job.
     
    • Thanks! Thanks! x 1
  16. 413

    413 Well-Known Member

    Messages:
    680
    Likes Received:
    229
    Joined:
    Jan 28, 2019
    Location:
    NW USA
    Here are photos of the leak points. This is in a van so easy to photo this. I Cleaned it up real good so I can see where the leak is. You can’t tell what is leaking when it’s all greasy and dirty. I used Castrol super clean at the car wash. This one has a bad shift seal.

    First photo shows the shift linkage, there is a seal in the case. Then you can see the 2nd gear band adjuster nut and shaft and the front cooling line.

    Just because your neutral safety switch is old does not mean it is leaking. They have a nice seal ring that seldom fails. Just keep the dirt out when replacing it.

    The red arrow is pointing to the low band shaft, it has an o ring on it. If it leaks clean it good and cover the end with “the right stuff”

    3 pan gaskets, I like the cork rubber combo the best. The brown one is fine also . The black rubber one is a mot very good IMO. I don’t use them, seems too hard to compress and seal anything. This applies to valve cover gaskets also.

    4C5BA102-CB66-46FF-82B0-42961B586D6E.png

    F8AED007-1B4E-41B4-A4B2-1E089F703202.png

    38F87640-EC21-4B32-A606-306CD17E4C27.jpeg

    BE1B849B-68D1-4453-9A91-5E5C4620723F.png
     
    Last edited: Aug 30, 2020
    • Thanks! Thanks! x 1
  17. Big Terry

    Big Terry New Member

    Messages:
    16
    Likes Received:
    5
    Joined:
    Aug 23, 2020
    Location:
    Central Ohio
    This is one of the most overlooked items when rebuilding,probably 75 % of the hard to find leaks,I've been there.

    38f87640-ec21-4b32-a606-306cd17e4c27-jpeg.jpg
     
    • Like Like x 1
    • Thanks! Thanks! x 1
    • Agree Agree x 1
  18. HWYCRZR

    HWYCRZR Senior Member FCBO Gold Member

    Messages:
    2,819
    Likes Received:
    3604
    Joined:
    May 13, 2015
    Location:
    Fargo, ND
    Real Tennessee Gaskets. Orange silicone. Last pan gasket you will buy. Follow the directions and don’t over torque.
    Pound your pan flange straight on a block like mentioned above. They are re- usable when you change your filter. Fixed my seeping and dripping around my pan.
    3362D6C3-8430-4EC6-8877-EEE3AEB380F6.jpeg 46DD39F9-F83D-48CF-9679-CB19AA930529.jpeg
     
    • Thanks! Thanks! x 1
  19. CanCritter

    CanCritter Senior Member

    Messages:
    4,774
    Likes Received:
    4132
    Joined:
    Apr 9, 2014
    Location:
    alberta
    l avoid anything alum that includes fluids....my alum tranny pan in my 91 weeps...have had other issues wth alum...if cast l avoid....billet shouldn't be as porus as cast lm thinkin
     
  20. BIGBARNEYCARS

    BIGBARNEYCARS Senior Member FCBO Gold Member

    Messages:
    4,036
    Likes Received:
    2644
    Joined:
    Dec 10, 2012
    Location:
    SHADOW OF MOTHER'S PROVING GROUNDZ
    YUP, Thatz the one I'm talkin' about. Some where between red and ? ... BTW HWYCRZR, Iz the Dirt Track in Fargo still in business? Had a very enjoyable evening in the standz there in ? '77 I think. Found out about the track when I was down for the weekend in Moorhead with an Over Dimensional load and couldn't deliver in Winnipeg 'til Monday. Jer