Decided to change the oil in the ZF. Can't budge the drain plug. Does it make a difference if the ZF is cold or hot?
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my answer is not ZF specific.
the threaded bore in the aluminum casing will expand when hot and thus "loosing" its grip on the plug. this would be more so if the plug is steel as it does not expand as much.
the reverse should be heeded when reinstalling.
would you mind educating me on this plug. is it a straight thread with a sealing face? if so, is it gasket or oring
the shop manual illustrations look like they may be tappered threads
the threaded bore in the aluminum casing will expand when hot and thus "loosing" its grip on the plug. this would be more so if the plug is steel as it does not expand as much.
the reverse should be heeded when reinstalling.
would you mind educating me on this plug. is it a straight thread with a sealing face? if so, is it gasket or oring
the shop manual illustrations look like they may be tappered threads
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The plug (105) I assume to be a tapered thread as there is no gasket. I am making the same assumption as you that the aluminum case will expand faster than the steel plug and it will loosen.
It is a tapered plug.
I replaced both the drain and fill plugs with straight thread/sealing washer plugs sourced from my Toyota truck. I did hand work the sealing areas on the case with a file to ensure a good surface there to seal against and have not had a drop since. It's a much better solution in my opinion.
Steve
Steve
I wished I had thought of that when my ZF was torn down.
use a little anti-sieze around the plug next time you have it out. It should not give you any problems later.
I have teflon taped the plug since I got it back from Butfoy's shop in 1990. He did the same. If Roy did it, then it's good enough for me. Change it every year when I flush to oil. Not a drip and never sticks.
Simple works best.
Simple works best.
NOW you tell me! 
Success!