The 23-year-old, who is an England U-19, U-20 and Sevens international, joined the Aviva Premiership club in the summer of 2010 from Worcester Warriors.
Cox is vying with Andy Hazell and Akapusi Qera for the openside flanker berth at Kingsholm but can also play at No 8 or blindside flanker.
"They're two international flankers so I know exactly how well I have to perform in order to get a game," he said.
"But, fair play to Brushy and Hoggy, they're 100% honest with me. They tell me what I'm doing well, what I need to work on and when I'm likely to feature.
"They're straight down the line with me and a big part in how my game has developed since I came to Gloucester."
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.