Installing Kenwood DDX318, ran into a hiccup

Does anybody know if you are supposed to use the metal "sleeve" that the headunit comes in? It's the bracket that you have to bend the metal tabs to hold the headunit in place, according to the directions. There are no holes drilled on the sides for the side brackets to bolt to the headunit.

Am I supposed to punch holes in that sleeve where the screws go or what? Hope this makes sense, install was going well until I tried to figure this out.

Thanks in advance...

 

I didnt use the sleve when I installed mine. There was screw holes on the unit that the brackets fit perfectly too. Then i bolted it the the cab. Dont know about Kenwood but would think it would be the same. Check for screw holes on the new unit. Pictures also help.

 

Do not use the sleeve. Bolt the brackets directly to the chassis of the HU. The holes will line up perfectly, if they don't something is off. Keep things simple and you won't have any problems. If things start to seem complicated stop what you are doing and rethink the process, you will probably find that there was a simple solution to whatever issue you ran into.