My kitchen aid mixer is leaking what seems to be a brown liq. maybe oil where the paddle inserts into the mixer.

Maureen it's probably not a good idea to put to put all that personal information here on a very public forum. Contact Kitchen Aid and ask them for contact information for the longest established authorised repairer in your locality.

Kitchen Aid is 100% correct. The cause of the problem is age and lack of regular use, the oils in the gearbox grease separate from the solids over time and the oil then leaks out at the planetary and sometimes where the 2 case halves join under the silver trim band.
If you are up for a small job knock the chrome trim ring around the planetary off and clean it out and wipe around the area it covers. It is called a drip ring for good reason, you may find it full of oil.
The grease Kitchen Aid used in their mixers is Food Grade and it's harmless.

Since you have not given a make...I'll take a stab in the dark and bet you have a kitchen aid...simply because you mentioned the dough hook. Kitchen aid has 14 models of stand mixers. You can match yours up and look at available accessories at www.kitchenaid.com

take off the chrome ring around the rotator. remove the screws that were hiding under it. pull off the rotator and replace the "O" ring on the shaft.

It can be. This may require replaing the plate that the shaft comes through, since there is now enough play to allow the grease that is in the nead to leak through. You can find the parts online, but be ware, it involves tapping out pins and undoing many screws. Manuals are available online at Kitchenaid.com

There are 2 possibilities, the attachments are worn out where they go on the shaft, simply replacing them could fix it, the other is the shaft is worn out inside the planetary ( where it spins), if it moves allot, 1/8 " or more from side to side, the housing is probably worn, and the planetary needs to be replaced, easy job, don't know cost, a new mixer may be in order.

A TV show "How it is made" was in the Kitchen Aid factory and they used a thick grease and no oil in the mixer. Does your unit get hot? Maybe its melting the grease (dark brown)..

The solution?...the oil leak is a very common problem with the kitchen aid mixer. If you don't use your mixer a lot the gasket dries out and the gear casing oil leaks. Doesn't that sound like a tasty ingredient to add to your cookies?? You'd think that a gasket wouldn't dry out so quickly...but it does. You'll spend about $125 to get it fixed at a shop. If you seach the net (consumeraffairs.com) you'll find hundreds of complaints just like yours....and mine. Kitchen Aid's response is basically tough luck, we got your money.

I went to Kitchen Aid'sKitchen Aid's web site and had an on line chat with a tect support person name Jessica. She told me that if the mixer is not used a small of oil will leak out. to fix the problem you must run the mixer for a few minutes every month or so. This seems to work.
Rick

I have this problem too -it is rather common if you search the web. There was a suggestion posted on this site about what to do. See http://www.fixya.com/support/t125253-mixer_leaking_oil I have also read about other people taking it to a Kitchen Aid repair place where they repacked the grease for about $45. I took mine apart and there is gobs of grease around the gears. Right now I am still trying to figure out what to do. I am going to have my father look at it to see what he thinks since he is good with motors. The Kitchen Aid web site says that the grease is FDA approved, so at least it's not going to kill you if a little gets in your food. Their suggestion is to take it out and run it for about 5 minutes at least once a week. They say it leaks if it is not used often enough. That logic doesn't make much sense to me, but you could try it. Mine seems to leak more when I run it because the grease heats up and liquifies more. I hope that helps. I'll let you know what happens with mine, once it's fixed. Lisa