These guys did a fantastic job, quality work, take there time with diagnostics, they work with you and keep you updated along the way. Couldn’t be happier with the price either with the extensive amount of work they did. 11/10 highly recommend.

I’m not one that likes taking my truck anywhere but I needed some stuff done that I didn’t have the time or space to do, and I’ve heard good things about Knox and they definitely lived up to it. Britt was super professional and went out of his way to answer any questions I have and also this is probably the only shop I’ve ever been to that hasn’t tried to screw me over on price. Will definitely use them again no doubt

Britt is an extremely thorough mechanic that takes care of his customers. He goes above and beyond to make sure you are getting what needs to be done all while being extremely affordable. He tells you exactly how it is and doesn’t try to throw you the salesman pitch just to take your money like most shops do. I’ve called him countless times over spur of the moment or last minute situations and he is always so welcoming to assist in anyway possible. I would give this shop 5 stars any day of the week!

Used my truck as their personal metal scrap bin to relocate. While they were moving used to move trailers while truck was not in running condition with out permission again.

Thorough diagnostics, expedited repairs at request, found issues other missed, and was very progessional. Highly recommend.

Awesome employees easy to deal with

Britt is a top notch mechanic! He is very professional, honest, and up front. If you ned anything done on your vehicles this is the shop to be at. Period. Give em a shout today! You will not be disappointed!

Honest stand up dude. I recommend his work 100%

Very busy but great service, tech stopped what he was doing to answer any questions that I had

I would highly recommend this place for all of your vehicle repairs and needs. They are great people and the quality of work is by far the best. Go by and see Britt! He will definitely take care of you!

Extremely knowledgeable and professional place to go. Had my truck running smooth and better then ever. Definitely willing to adapt and help customers. Will go there for any questions and future needs. Great service, makes you feel like you’re part of the family.

Owned by a husband and wife who are both veterans. Brit (the husband) absolutely knows his stuff hands down, his prices are fair, and he will bend over backwards and do whatever he can do help you out. If you are looking for a shop thats not going to try and rip you off and does quality work this is the one.

My 2014 6.6 had some knocking. It was coming from between the trans and the engine. Took it by a couple places, just to get lied to. They told me it was the engine and I needed to replace it. Said they could fix it for me too.(go figure) Went to Knox Performance Diesel & Offroad told him what was going on to see what he would say. Took a look at it and figured out that, I cracked the flex plate. The man was honest as the day is long. Gave me a great price. Had the job done alot faster than I thought, with great work. He took the time to show me and explain why I was hearing the knocking. Felt like family here! Really helped a fella out in a pinch. Will be coming back. Thanks again!

Britt did a fantastic job with my front end on my 2014 F350. He’s very knowledgeable and professional and did an entire look over on my suspension and corrected my issues. Highly recommended if you need any help with diesel truck or suspension.

Excellent customer service. On time and on budget. Great work from a great veteran owned business.

Had Britt look at a truck before I flew 1k miles to buy it from a dealer. Gave a detailed breakdown of everything that was good and bad about the truck. Knows his stuff and did a great job, went above and beyond anything I expected. Not sure of he does it for everyone one, but he didnt charge a thing for doing it. Bought the truck and was everything he said it was.

Took my truck in and had it back the next day with the problem fixed. Very good service at a great price. Will definitely be taking my Cummins there in the future.

I had been looking for a stock Chevy Duramax for a future build and the fact that it would be my first diesel I decided to call the local diesel performance shop around the area, I called Knox performance diesel and off-road( a family owned and operated business) and asked if I could bring the truck by; to which he said yes, and later that afternoon he ran various types of tests on the truck though it was an older model it still was in good shape, not only did Knox save me money by checking it out before I would commit to paying the seller but the customer service was great! I’m upset I’m not local because if I was I’d let these wonderful people build that Duramax for me. Knox and his wife are great people, I highly recommend their shop if someone’s looking to get maintenance done on their trucks or looking to build their truck.

I highly recommend this shop the ower is professional and easy to work with. He also knows his stuff and will diagnose your issue quickly and shoot straight on whats wrong with your truck.

By far the best diesel repair shop in the Bell County area, if you have any repair or performance needs. Look no further than Knox Performance Diesel and off-road!

Best diesel shop in Killeen! Locally owned small business, with the best service!

Awesome people, awesome shop. Highly recommend, I will definitely be using them again!

Upon meeting Mr Nox, he accessed thw situation. Told me what he thought! On time.Thanks alot !!

Professional, outstanding work. Awesome shop and great costumer service. Highly recommend this shop.

Great people to work with and quality of work is top notch and fair priced

Fixed my truck and didn’t break my wallet.

Finally a honest mechanic in Killeen !

High level of expertise and professionalism