[Milsurplus] Mod transformer

[Rick Brashear]

I have an old military modulation transformer and I'd like to ask the 
opinion of the group about it.  Following is all that is printed on it 
or all I can make out:

Family 14     Modulation Transformer
20K primary - 8K/7K/6K secondary
Spec 22? (can't make out the last number or letter)
Mil - T - 27
NL 80976 
Grade-1      Class-A
Freq Response 100 - 4.5KC  +/- 1dB
Peak Working Voltage 4800
Electronic Transf Co.

The transformer is oil filled and I can hear it sloshing around inside.  
The thing I am concerned about is when it's turned over I can hear the 
sound of something that sounds metallic rattling around inside.  It 
doesn't matter if I turn it from side to side or up and down or cross 
ways, it still rattles.  What could this be?  Is it a normal rattle?  
The continuity is good on all windings and there are no shorts to the 
case.  I have not run any power through it as I am concerned about the 
rattle.  Does anyone know anything about this transformer?  It weighs 
about 35 pounds, I'd say.

Thanks,
Rick/K5IZ