Ecomike; I highly respect the knowledge base you have as a; "materials science-chemical engineer", but remain, in defense.., unconvinced as per epoxies, and their bonding properties within, not necessarily between epoxy, and another material, such as aluminum, but within the glue it's self. I attempted a layman short handed offering that epoxy is not the end-be-all as per a water proof material, as it is not.
I really don't think that your transmission part with epoxy holding it together with aluminum, or whatever, is totally compromised from maintaining adherence, but I tend to also side with those that have had bad results from any kind of water mix within their transmissions, for whatever time periods. None of these detriments are something statistically known by me, either in the lab, or the garage, or from back yard shady tree mechanics such as many of us.
My usual thinking revolves around epoxy, and wood. However when shown that other members here have had some experiences with automatic transmission bands/epoxy/metal having a "deterioration" failure rate.., of some sort, I too hesitate thinking all is good, including the additional problem of aluminum corrosion, blah, blah, but rather agree that a complete tear-down might show you which way to proceed, or to perhaps just replace with a known clean well functioning tranny.
My take is based only on empirical results of using epoxy in a water environment, i.e., real world applications of said. Too.., I agree with all others that have the opinions that only negative results are the result of submerging your questionable part(s) in water solutions; salty, fresh, contaminated, etc., that all remind me as to the various consequences of et al, either in the short, or long term.
My layman research into epoxy is only determined by my specific inquiries into applying polyester resin, or epoxy resin to plywood. Either can be shown to allow water from fresh water, or seawater to 'leak' through into a plywood boat hull. Epoxy is a superior glue, but still does not provide a leak-proof ply-boat hull. Not from any impact, (which hastens leaks due to shattering through the epoxy/glass, or poly/glass layers), but from a more mechanical micro-infiltration that exists between the molecular chains within either glues. Water under pressure, such as the displacement of the hull in water exerts, will find it's way through either poly, or epoxy glues.
For example as per ply-boat hulls; Merely 'painting' only a simple one layer of a clear mixed coat of epoxy onto the skin of a blue water live-aboard cruising ply-boat hull is doable, (not talking a canoe here), but not smart, i.e., less strength without glass.., and if said is to stay in the water, i.e., not trailered to dry out then water infiltration will be a major problem. "Dry Out" is of concern here. For strength epoxy is applied to hull, and then when tacky, layers of glass, i.e., woven/roving, mat, and tape, are laid up, and then saturated with more epoxy, again glass, and again epoxy, etc., until such layered build up is a satisfactory thickness for end use. The addition of a 'gel-coat', possibly over other preceding layered barrier coatings, and too.., other additional layered barrier coatings all together attempt to impede water infiltration through either type glues. Someday there might be another superior type glue that will be truely waterproof.., but I've seen none, know of none, nor has anyone around the marine community around my parts. So.., we are always looking for the next best secondary barrier coat over epoxy needed to prevent water from seeping through that initial epoxy barrier coat. Wax seems to be the best old school barrier coat over either poly, or epoxy coats. (also cheaper than four hundred dollar per gallon super-duper stuff on the market today).
In our local fishing industry, hulls made of plywood often have an inch, or two thickness of glass, and poly-resin. (lighter hulls of plastic/foam cores=less thickness). I consider thin poly-glue/glass layers to be inferior as water easily passes through over a shorter time period, and rots the wood substrate below, and separation results. Yes an inch, or two provides much strength, but part of that reasoning of such uber thickness is to keep the water out on a longer time-line, i.e., providing a longer longevity of the craft's usefulness, (even if in those places/areas where the poly/glass separates from the plywood, read existing as the wood remains as only a rotted "hull-form" at this point). This problem of water infiltration is such so that hard working fishing boats using poly glue are best dry-docked for better than 3/4 of a year in order to 'dry-out' the boat hulls. (way less time for epoxy sailboats). Most likely even less time in Texas as for here in Alaska these mega $ boat hulls with glass saturated with water end up freezing for many months which mechanically further destroy the bonds of the glue, and the glass, thusly mechanically allowing for more fissures to result, and thusly more future water infiltration to be more easily resultant unless pre-fishing season repairs/coatings are applied prior to launch, like another gel coat. Unlike the poly boats, epoxied Sailboats are often just waxed before launch.
Epoxy on the other hand is a superior glue but still fails the water infiltration test over a longer time than poly's shorter time period. The very best protection I've ever found of keeping water out from infiltrating epoxy is best done by waxing the epoxied hull with hard floor wax. Surfers do too, but for another reason, lol). Wax will fill in those micro-fissures that exist in epoxy glue, (and poly). Without that final layered barrier of wax.., water of any type will thusly infiltrate through the epoxy, through the glass, and finally the 'wet' wood allows mold, and other bugs to live, and rot out the boat form, (even though epoxy will not separate from the wood, unlike poly).
Remember this too.., marine grade plywoods, (although not as primo as in time past), are just layers of veneer glued together with epoxy. If epoxy was water proof, then water would not penetrate through a layer of wood, epoxy, wood, epoxy, and so-forth. It does, and that empirical result, in costly repairs evidence, seems to offer a different result from that which is established in a lab, or black-board somewhere determining the differences of a product whether hydrophopic, or to a lessor aspect of this discussion; hydrophilic compounds.
Although I was correct in saying that water is a universal solvent, it is correctly pointed out by you that this universal solvent is not applicable to the detriment of epoxy, nor applicable, perhaps, to the issue at hand, i.e., wondering if the metal/glue/plastic/nylon/bands, etc., are problematic with the introduction of water into your transmission causing separation of said parts. My major point, again as a layman's understanding, is that water, a solvent never-the-less, will get mechanically through epoxy, and not for reasons of whether epoxy is attractive to water, or not. It does not matter, i.e., water will travel through epoxy. I'd like to see images from an Electron Micro-Scope showing such.., but that's a near impossible device for me to stand in line for, i.e., costly, and due to subsequent time I have not, and the required scholarly White Papers leading to such use, etc.
My hope is that you will follow through with your possible tear-down-inspections/replacements, etc., so as we might find out what your real world experiences are with that flooded transmission. However, I somehow feel a flush might just be adequate, but others here have pointed out more skeptical opinions that cause me to be somewhat on the fence regards this issue of yours, (and others, whether from salt, or fresh water, and other in-solution contaminates, etc).
I hope this clarification of mine goes some way in my wonderment of; the big IF your tranny epoxied part will be compromised, or not.
Best wishes on your flooded project.
