For those with Allison MD3060-6 dipstick plug leaks.
This is a double post.
So, I am making this thread in case anyone else has this same leaking Allison six speed issue in the future. This is a fairly simple DIY repair.
My 1996 Diesel Winnebago has the Allison MD3060-6 6 speed transmission and those have two holes for dipsticks from the factory so they can be used in a variety of applications, one is used and the other is filled with a plug. This allows OEM's to use either hole for the dipstick.
From what I understand the units prior to 1997 like mine use an older style rubber "welch plug" with a bolt head on top and a swell-nut down in the hole to retain trans fluid. Sounds simple, tighten the nut and the plug swells....until everything spins and you cannot get it to swell, or seal.
As an aside I should mention that these transmissions do not have a traditional "Pan" like many others, and when the transmissions sit for any length of time the torque converter lets the oil drain back into the trans and that can easily push it's way out of that plug, and even geyser out when you remove it, so be prepared for that.
From what I understand the plugs were improved after 97. I do not know what they were replaced with, however the part number for the seal that I gave the counter was superseded already with a newer part number.
Mine has been leaking, last fall I removed it after the coach had sat for a while I had a gallon of fluid soak my driveway, but I did get the existing plug with the bolt head on top to snug down a bit and that helped for a while, but it was not a durable repair.
So, I googled around a bit and found the newest replacement
and picked one up today. It is two different part numbers.
The plug is #29530328 Retail $19.60
The current seal is #29546229 $4.53
The counter tech told me to insert the rubber seal into the trans body, then insert the hard plastic plug.
Here is a photo for reference. The plug has prongs that retract when pushing past the seal. I am going to install mine later this week before I depart for vacation, my plan is to remove the plug immediately after shutting off the engine to avoid "Drain back" from the converter. If it makes a mess again I will share.
I hope this helps someone, it would have helped me a bit to know what could be done and how simple it is. If your pre-97 seal plug is leaking it can be removed with a small wrench fairly easily, and possibly with no tools at all if you can just lift your current plug out as the new plug is a tool-less installation.