OK, time to update ... what would you say the worst possible scenario could be? If you guessed replace the transmission you're right. The fluid was contaminated with engine coolant. How is that possible? Take a look at the attachment. This cooler failed internally and mixed the fluids. How it works and where it is located are unknown to me as the coach is 50 miles away at Stewart & Stevenson's Allison repair center in Commerce City, CO and all my manuals are in it. Also take a look at the other attachment which is a Service Information Letter from Allison. This memo states that contamination from water or glycol >0.2% is detrimental to the reliability and durability of the internal components and should not be used. In my case the wiring was affected therefore sending erroneous signals (fluid temp 275 degrees). All the internal components detailed in the SIL are beyond salvaging. Now the fix ... rebuild the transmission as outlined in the SIL or buy a rebuilt Allison Certified replacement? Cheaper (that's a laugh) to swap with a rebuilt unit. Looking at about $10,500 for the unit with about a $4,000 core credit. And in the Allison SIL doc is a quote from Beaver for the cooling unit at $957. If I get away with $8,000 I will consider it very lucky (ha!).
Mike at Beaver Parts pulled some strings yesterday and said the supplier can build one in 1-2 days, miracle! These are not off-the-shelf units so each one is built from scratch. They will not drop ship to S&S so Beaver is going to overnight to Commerce City. The transmission is coming out of Minnesota ground freight and should be there mid-week, another miracle in my book. Then time to put back together and test puts the coach back in my hands 10/9 BEST case.
What to take away from all this ... the transmission fluid looked absolutely clean when I looked at it at the first repair shop and the fluid was not tested there. So, if your coach is an older unit, next time you check the transmission fluid HAVE IT TESTED FOR CONTAMINATES! 0.2% is a very small amount. What is that old adage ... an ounce of something is worth something else that won't cost you thousands of dollars? I learned an expensive lesson here. Maybe this has been discussed here before, I didn't look. But if you know someone that is in my boat you may want to share this tale.
I'll update again once this is behind me.
Save travels!