I am changing the filters and fluid on my trans. I removed the drain plug at the rear of the sump, the drain plug at front of the sump (marked "main" on the pan casting), and the filters. The Allison materials say it should be 19 quarts to refill. After two days of draining, I have well less than 8 quarts including spillage and filter suck-uppage. Stick showed full recently, and there were no signs of leaks or seepage.
Am I missing something?
oldMattB
Matt, I am sure you will find this Allison publication of great interest.
http://www.allisontransmission.com/servlet/DownloadFile?Dir=publications/pubs&FileToGet=MT4015EN.pdf (http://www.allisontransmission.com/servlet/DownloadFile?Dir=publications/pubs&FileToGet=MT4015EN.pdf)
Enjoy
Dave M
Interesting. My MD3060 always drains almost exactly 19 quarts. The drain plug is a square drive in the front driver's side of the transmission just as shown on page 51 of Dave's link.
I always drain hot, but as low a viscosity as ATF is, even if drained cold, it shouldn't make a material difference. 8 and 19 is a HUGE difference.
I would button it back up to keep dirt out and call Allison on Monday and get their input: Allison help line 800 252 5283.
Any particulates or indication of something that could be impeding fluid flow?
Brett
Square drive? Hmmmm.... Waiting for document to download.
oldMattB
Yes, 3/8" rachet/extension removes the drain plug if I remember correctly.
I have not removed the main drain plug apparently. I have a mechanic's guide from 1994ish that showed the "extra" bolt next to the main filter as a drain (LU pressure tap). I am now sure that it meant the drain for the filter and not the sump.
All makes sense now. I will investigate it further tomorrow - almost time to go sing!
oldMattB
Oh, THAT plug...
It is as Wolfe describes it. I will add that it has a very short head and is in a recess, so it is hard to see without being under it.
I will print the guide for later reference.
oldMattB
Glad you found it. Suspect you got your full 19 quarts out.
You will want to verify that the bolts you removed did not release anything held into the base of the transmission. Past my pay grade, but you may want to take a photo showing the bolts you removed and swing by an Allison dealer to confirm before you start it.
Brett
I have heard stories of things in Allison transmissions being released by removal of external bolts. Both bolts were hollow, had seals on them, and I have confirmed by the cool document above that they are pressure test ports.
oldMattB
We'll try to get this posted to the Files Library shortly. The file size (12 MB) means Steve will have to try and crunch down the document in Acrobat if possible, or break it into several files.
Michelle