Thanks Driver for the addition info. I hope dinkie0720 finds this info before he buys 5 gal of transynd.
To drain the Allison 1000 MH you just remove the plug. I will not call it a DRAIN PLUG because no graduate Mechanical Engineer, Design, or Mechanic from the school of busted knuckles would place the plug above the bottom of the pan
,thus leaving all the nasty to lay in the bottom of pan to mix with the fresh fluid
.
I would like to see the DFMEA for the Allison Engineering design review and who sign off on it. GM Powertrain Engineering must have been eating donuts and missed fact you must remove the pan to remove all the Nasty stuff. I guess that's why Ford Truck is #1.
On all the vehicles I have owned with Auto trans and did the trans flush I had to drop the pan, then would wipe all the clutch, metal, sludge and debris that had settled on the bottom.
My next flush in 2016 I will drop the pan and clean it .
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2009 Safari Simba 34SBD, WH W22 GM 8.1L 6k Sterling tow bar, US Gear Unified Tow brake,98 Blazer 4wd, Remco Prop shaft, Alaska Tested