Humvee DIY – How to Make a HMMWV Tunnel Cover?

Humvee DIY – How to Make a HMMWV Interior Tunnel Cover? Wait…. There is a tunnel in a Humvee? Most passenger cars and trucks have a small hump in the […]

Humvee DIY – How to Make a HMMWV Interior Tunnel Cover?

Wait…. There is a tunnel in a Humvee?

Most passenger cars and trucks have a small hump in the center of the floor for the driveline to pass under the body. A key design feature of the HMMWV is high ground clearance with a low overall center of gravity. To achieve this the body tub was lowered down around the driveline and the driveline was raised. This required that the driveline pass right through the body and passenger areas in the HMMWV. The “tunnel” is the big, raised, flat section between the seats in the HMMWV that encloses the driveline. The tunnel extends from the doghouse cover all the way back until it transitions into the truck bed.

the “tunnel”, looking from the rear forward. Picture taken between coats of LizardSkin.

How to Make a HMMWV Interior Tunnel Cover

Bob N posted this pic of his completed cover with green painted plywood


A few reasons for covering the center driveline tunnel in the HMMWV come to mind:

  • Provide a grippy surface so things placed on the tunnel don’t slide around
  • Impact protection for the aluminum tunnel
  • Sound and vibration reduction
  • To block and possibly reflect heat down instead of into the passenger compartment
  • Because the military did it 🙂
  • It looks cool

“I just finished my 3/4″ horse stall mat. Makes a huge difference in sound and heat.” -Michael

What you need to cover the center HMMWV driveline tunnel

The dimensions of the top of the tunnel in the Project Humvee Battlewagon are roughly 31″ wide by 53″ long. However, I have a non-standard mounting of the 4 man cargo divider. So, I recommend that you decide what coverage area is right for your needs, then cut the HMMWV tunnel cover to the appropriate dimensions. Some folks make a smaller section for the front where it is narrower to accommodate the shifters and between the legs on radio shelves, then a long rectangle shaped section aft of that.
How to Make a HMMWV Interior Tunnel Cover - horse stall mat

Michael B posted this pic of his tunnel covered with horse stall mat

There are three materials folks typically use to make a tunnel cover for their Humvee:

  • 1/2″ plywood – You can order smaller sections and piece together or get a bigger piece locally. If you are going for the military look, then you want wood and will need to paint it as described below.
  • Rubber mat: I like 1/2″ – 3/4″ horse stall mat – I prefer 3/4″, but it is heavier and more costly to ship. I also prefer this rubber mat vs wood. Horse stall mat also makes great floor mats that deaden sound and vibrations. Look for mat with little channels molded into the bottom if using for floor mat, as they will let water run out from underneath. Some folks also cut down rubber truck bed mats, which are thinner, but easier to ship.
  • Automotive carpet: I’m not going into this since the purpose and use of carpet isn’t really consistent  with THIS project.
  • For plywood:
    • Kilz primer (2 coats, both sides, of the type appropriate for the paint you select)
    • Paint (2 coats)
    • Optional: Reflectix insulation – put under board to reflect heat
    • If cutting the plywood to fit, you will need an appropriate saw. Some folks just square off the corners with a circular saw and call it a day. Others make elaborate cut-outs for the shifters and round the corners, requiring a drill, drill bits and a jigsaw. You might also want to relieve the edges a bit with a router.
  • Self tapping stainless steel screws to secure the plywood tunnel cover – 3/4″ truss or washer head screws for 1/2″ plywood, 1″ truss or washer head screws for 3/4″ plywood or horse stall mat and a drill driver.

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HMMWV stuff

More HMMWV articles can be found under the Humvee category menu above or by clicking HERE. You might also like the HMMWV section of our Amazon store where we have listed lots of replacement and upgrade parts for Humvees. We have also found a lot of HMMWV parts on eBay (link).


Please leave a comment if you have suggestions on other HMMWV upgrades should consider, or you have done upgrades that we can share on Gear Report.

The Project Humvee Battlewagon

Gear Report acquired a real HMMWV (High Mobility Multi Wheeled Vehicle) from the US Army for use as our official field and shooting range vehicle. We have already posted about some of our upgrade projects (Project Humvee Battlewagon article links) and have a lot of really cool projects on the way. Consider subscribing so you don’t miss any of the cool reviews as we post them.
Here is our Project Intro (link) and our list of HMMWV upgrade projects.

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Originally posted 2017-07-04 11:25:05. Republished by Blog Post Promoter

About Jeff

Jeff is the Editor in Chief of Gear Report and a National Shooting Sports Foundation Media member. He reports on the outdoor industry, reviews gear for camping, hiking, shooting, hunting, paddling, backpacking and other active pursuits. A USAF veteran, Jeff earned a MBA in Marketing and Health Services. He specializes in consultative selling and internet marketing. As the VP of BD & Marketing, Jeff provides sales and marketing leadership to MGECOM, Inc. and helps acquire new clients in need of solutions for online merchants in need of Affiliate Marketing program management. Jeff founded and manages Cress Sales & Marketing LLC, offering online sales and marketing consulting and services to online merchants and service providers.