Front Bumper Filler & Radiator Guard for Trimmed GX460 Bumpers

[mtnco]

Been working on this one for a while.

Late 2024, a friend and I trimmed our GX460 bumpers after some ground hits on the trails. Loved the clearance, but did not love the exposed A/C condenser and radiator, not to mention the unprotected engine intake and the fender liners flapping in the wind.

Spring 2025, I started measuring and trying to design something better. Built and tested a couple prototypes over the summer to make sure it didn't whistle or rattle and was easy to put on or take off, and now it's dialed.

I released it as a pre-order on my website with a pre-order discount and free shipping. Pre-order is available through end of January. Fits 2014+ GX460's.

It's made of 5052-H32 aluminum to keep it lightweight, since it’s partially supported by the bumper cover. It attaches to the lower lip and corners of the front bumper cover, the fender liners via adjustable brackets, and to the vehicle frame via a radiator guard. It's designed to attach to the stock crash bar too, though this isn’t required if, say, the crash bar is removed for a hidden winch mount.

The whole thing puts structure back in the bumper cover and keeps the fender liners out of the tires. EPDM bulb seals on the leading edges allow the cover to move a little without rattling or leaving large gaps. And, of course, the radiator is protected.

The before & after photo shows a late prototype; the updated radiator guard now mounts to the lower radiator support instead of the skid plates, making it more universal to fit most skids—including stock.

Hope you like it!

More details in the links below.

• Webpage: backPAC – Bumper Filler & Radiator Guard, GX460 2014-2023
• IG: Instagram – Bumper Filler & Radiator Guard, GX460 2014-2023

 

[r2m]

Looks awesome!
Question: will you provide some sort of template so one knows where to trim, not too high or too low?
Suggestion: Is it possible to make a steel "bull lip" as an additional plus add-on option (for more $$), that can be attached just under your plate, while using the same mounting points? This would at least give a little protection from small rocks, sticks and things. I'm thinking of maybe 3/4" to 1" steel tube running along the entire front lip.
Just spit wading here...

 

[jeremy j]

Love the improvements and would really like to purchase one but looks like you maximum cut line is lower than I cut mine. Is there no option for the people that already trimmed?

 

[mtnco]

Looks awesome!
Question: will you provide some sort of template so one knows where to trim, not too high or too low?
Suggestion: Is it possible to make a steel "bull lip" as an additional plus add-on option (for more $$), that can be attached just under your plate, while using the same mounting points? This would at least give a little protection from small rocks, sticks and things. I'm thinking of maybe 3/4" to 1" steel tube running along the entire front lip.
Just spit wading here...

Thanks!

Regarding the template, I have a basic diagram on the website but plan to include more details when I finish up the installation instructions.
Cut line is basically a flat plane from the center section.
Option 1:

Option 2: This is the cut line I chose for my GX.

Option 3:
Anywhere in between Options 1 or 2 (or lower).

I hadn't thought of making a "bull lip". I'll have to keep that in mind for the future. Probably not steel though.

 

[mtnco]

Love the improvements and would really like to purchase one but looks like you maximum cut line is lower than I cut mine. Is there no option for the people that already trimmed?

View attachment 4063277

I could see something being possible, but not as it's designed right now. Really needs that front lip of the plastic bumper cover to attach to. Also, it can't be mounted any higher due to the vent rib sitting partially under the stock crash bar, as shown below.

Just thinking out loud here: I'm estimating that your cut is about an inch higher than mine, meaning the filler plate could be designed to attach directly to crash bar without spacers (if the vent rib were removed).

I'm not sure how much support the front edge of the filler plate needs, but one option would be to create small attachment brackets that get screwed to bumper cover. The screw heads would be visible.

I'll ponder this some more to see if I can come up with a good solution.

 

[Ohio Nori]

This is great. Curious if this would work if the center valence were removed, but the sides were not cut?

 

[mtnco]

This is great. Curious if this would work if the center valence were removed, but the sides were not cut?

I believe it would.
The steel brackets that hang off the crash bar to support the lower part of the bumper cover would still need to be removed.
Thinking the lower parts of the fender liners would need to come off, too. Or be trimmed somewhat.

 

[Arailt]

Interesting. How does the air induction cut sound at highway speeds (80ish)? Looks like it could whistle

 

[mtnco]

Interesting. How does the air induction cut sound at highway speeds (80ish)? Looks like it could whistle

I was worried about this but I have had zero whistling, including a road trip from Denver to St. Louis and back where we occasionally hit 80 mph.
And going each direction on I-70 through eastern CO/western KS, we experienced crosswinds, headwinds, and tailwinds. All the winds.

 

[Cold Iron]

That is an elegant solution and really wish it was available a couple of years ago when I did mine. Going forward I expect a lot of GX's will start being purchased for off road use and modified. Many existing ones have the cut higher and I didn't care for the look cut up higher. Bet I looked at more than 100 pictures of cuts and finally found one that looked right to me, like it came from the factory that way. Found a picture of a second one and that convinced me where to cut it. Right where you did.

Using a stand alone radiator skid still allows debris like leaves, mud and small sticks, to come into the radiator. You can see a leaf plastered to my radiator here.

Bent some bar stock to make some braces to help support the front of the bumper cover. Running into a snow bank and backing out without support for it is a good way to rip it off.

Last summer someone finally came up with filler plates for the bottom of the wheel wells so I bought and installed them.

You addressed every single one of those issues without piecemealing it together. Well done!

 

[mtnco]

That is an elegant solution and really wish it was available a couple of years ago when I did mine. Going forward I expect a lot of GX's will start being purchased for off road use and modified. Many existing ones have the cut higher and I didn't care for the look cut up higher. Bet I looked at more than 100 pictures of cuts and finally found one that looked right to me, like it came from the factory that way. Found a picture of a second one and that convinced me where to cut it. Right where you did.

Using a stand alone radiator skid still allows debris like leaves, mud and small sticks, to come into the radiator. You can see a leaf plastered to my radiator here.

Bent some bar stock to make some braces to help support the front of the bumper cover. Running into a snow bank and backing out without support for it is a good way to rip it off.

Last summer someone finally came up with filler plates for the bottom of the wheel wells so I bought and installed them.

You addressed every single one of those issues without piecemealing it together. Well done!

Appreciate that—the goal was to simplify what people were already piecing together.

On the cut line, I actually took inspiration from yours, right down to the brackets.

 

[mtnco]

I installed the updated radiator guard today. Fits like a dream.
This design mounts to the lower radiator support, so it plays nice with different skid designs. Stock skid still pivots like it should, too.

 

[mtnco]

Love the improvements and would really like to purchase one but looks like you maximum cut line is lower than I cut mine. Is there no option for the people that already trimmed?

View attachment 4063277

I spent some time under the GX today and I'm confident I can design a version to fit your higher cut. I will have to make a few modifications to the design, including moving the ventilation slots from the filler plate down to the rad guard.

 

[17LC200]

Great products. I need the radiator guard at minimum. Any clue if this will work with the Victory Blitz bumper/winch?

 

[mtnco]

Great products. I need the radiator guard at minimum. Any clue if this will work with the Victory Blitz bumper/winch?

Most likely, but could you take a picture of that area so I can confirm? I can’t tell for sure looking at their website or install video.

Similar to this angle but closer:

 

[jeremy j]

I spent some time under the GX today and I'm confident I can design a version to fit your higher cut. I will have to make a few modifications to the design, including moving the ventilation slots from the filler plate down to the rad guard.

That would be amazing. I was looking at mine and comparing and see why you did it this way. I think an option for those of us that already cut higher could be great. If you need any pics or measurement, let me know. I will 100% buy one if it works for my truck. I have been putting off figuring out a solution for over a year now and I'm tired of looking at those zip ties.

 

[mtnco]

That would be amazing. I was looking at mine and comparing and see why you did it this way. I think an option for those of us that already cut higher could be great. If you need any pics or measurement, let me know. I will 100% buy one if it works for my truck. I have been putting off figuring out a solution for over a year now and I'm tired of looking at those zip ties.

If you could let me know what these two dimensions are on your bumper (crease to cut), that'll help me confirm things.

 

[jeremy j]

If you could let me know what these two dimensions are on your bumper (crease to cut), that'll help me confirm things.
View attachment 4068846

Front is 1"
Sides are .5"

 

[mtnco]

Front is 1"
Sides are .5"

I finally finished up the design for a higher bumper cut. I wasn’t sure what to do with the venting since my previous rib vent design wouldn’t fit.

That sent me down a rabbit hole of reviewing OEM designs and thinking through the pressure gradients around the radiator plenum and underbody. The short version is that the slots don’t meaningfully increase cooling and aren’t strictly necessary, but they help stabilize airflow through the radiator across different operating conditions. It’s not something I was able to model or test directly, but it’s enough to convince me they’re a net benefit.

Given that, I ended up going with a simple row of slots rather than deleting them altogether.

The entire front edge will be wrapped with the same EPDM bulb seal used on the other version and a strip of Buna-N foam between the filler and crash bar will keep things from rattling.

 

[Ohio Nori]

Decided to join the pre-order! Worst case scenario I end up trimming the sides, but with 33s and the unsupported wheel well liners I end up with occasional rub in reverse, even after pulling forward with zip ties and heat gun massaging.