looks like this?

http://www.amainhobbies.com/product_...ion-Brace-Tube

In the 811e manual, the part number named "Aluminum Transmission Brace Tube" , is listed under the category " Chassis / Guards Optional "

along with the aluminum chassis braces (fr/rr) and the hard anodized chassis.

However, I don't see it as part of the installation for the 811e. Maybe this is for the nitro version? I think maybe its used to help attach the rear chassis support somewhere, or used on the center diff housing someway ... not sure really.

there is a similar sized hole on the rear alum brace:
http://www.amainhobbies.com/product_...-Chassis-Brace

im sure the nitro manual would specify how its used/installed.