Help me with DW0521 3/8 chuck to 1/4 impact driver converter

[dewalt_user_101]

I'm a new owner of a DC825 18V cordless impact and I just picked up the DEWALT DW0521 Quick Connect Impact Driver Conversion Chuck for this new drill.  My problem is, when I tighten the drill bit inside the chuck, it still seems to spin and never really get totally tight.  I can hold the chuck with my hand and give the drill full power and it won't spin out of my hand.  If I try to use a 1" spade bit in wood, it also has hardly any power and will just stop and spin inside the chuck.  Not the bit, but the chuck itself seems to be spinning inside somehow and you can hear it clicking as if it were an impact or something.  I also noticed that if I take my had and push forward on the round part of the chuck while squeezing the trigger on the drill, it spins inside the chuck but does not make any impact noise...it just spins totally freely.  I don't know if I've done something wrong or not using this correctly or what.  It would seem to be a very simple attachment, but so far it's frustrating me.

Anyone have some insight into this DW0521 part?

Thanks

Oh and here's my new toy :-)

[tmccarty]

you can buy quick connect spade bits from Irwin. they are 1/4" shank. I have no insight into the conversion kit though.

[dewalt_user_101]

I have several bits that will fit directly into my new drill, but I have a lot of other bits with round shanks that I need to keep so that's what this converter was for. 

[JKoltner]

Have you tried smaller bits?  Holding a 1" spade bit is an awful lot to ask of a small keyless chuck!

Is there anything "special" about DeWalt's chuck that disables the impact action of the driver?  I ask in that I've used impact drivers with 1/4" hex shanked bits in a pinch to drive hole, but for anything bigger than about 1/4" the impact action is kinda annoying.