AllisonTransmssion Oil Change

[Dragonten]

I believe my 53MY has M20 transmissions. I am looking for advice on how to change the oil and filter. I see the drain hose out the bottom do folks pump it out? Does the filter just get cleaned or replaced? How easy is it to remove & obtain?

Thanks

[SKYCHENEY]

Drain/pump out the oil. If you have the OEM canister filter, remove the canister and replace the filter inside of it. Or, get spin-on adapters and switch to spin-on filters for easier change next time. Napa has the filters either way.

[Pascal]

And don’t forget level needs to be checked with the engine running in neutral.

It’s been a while but I recall the screen needs to be cleaned, it s held by 3 bolts and can easily be damaged resulting in low pressure and no shifting.

[Dragonten]

So the screen needs changing or cleaning? Does anyone have the part number? Any idea roughly how much oil they hold? Do you pump it out the dip stick holder or use the hose at bottom? I take it uses straight 40 wt. I have oil change pumps but for some reason they are not attached to the transmissions.

Thanks,

[Captain Ralph]

Not all factory oil change pumps went to the clutches. Never figured that SNAFU out.

Use the same CF2 oil as in your main engine.

When you pump out the warm oil, Let it sit over night, then pump out again. Lots more oil will come out.
We also did this for main engine services. Amazing what you can get out the next morning.

[Pls]

So the screen needs changing or cleaning? Does anyone have the part number? Any idea roughly how much oil they hold? Do you pump it out the dip stick holder or use the hose at bottom? I take it uses straight 40 wt. I have oil change pumps but for some reason they are not attached to the transmissions.Thanks, The screen just gets cleaned. You will need a new gasket for the assembly. Diesel Pro Power has a good website to order parts like that. Do a good job cleaning the surfaces and installing the new gasket or you may have an air leak. Oil capacity is about 2.5 gallons, use the same 40 wt oil as your engines. Either the dip stick holder or the hose on the bottom will drain the oil, the hose may get more out. The filter canister has its own drain plug. Make sure and replace the transmission filter canister seal, it will typically remain inside the housing when you remove the canister. When you fit the new seal, make sure it is flat inside the lip of the housing before reinstalling the canister with the new filter. Also, the canister bolt has to be pretty tight for a good seal and you may have to retighten after your first run. There is a seal between the filter canister bolt and the housing. I don’t routinely change this with each service, maybe every third or so, but others may have a different t view.