"Rednexus" - 2007 GX470 Build Thread (2 Viewers)

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Dec 14, 2020
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I've been posting on here for a few months now, and decided to start a build thread. Some of these will be re-posts, others will be new material.

We've been a Subaru family for a long time now, which was fine when we had one kid. Once we had a second kid, and he got big enough that we could go on family camping and other outdoor trips, my wife's Outback just got too small. Last August we could barely fit everything in the Outback for a weekend of camping, even with a car top carrier. I also had an old beater '00 Forester that I had owned for over a decade, and off-roaded all the time (skidplates, AT tires, etc.). It was a great car, but way too small for anything over than two people, and limited off road with a 5-speed and no low range.

I started looking for a real 4x4 midsize SUV and learned about the GX470s. My other choice would have been an X-Terra Off Road 6MT, but they lack a 3rd row, lack a V8, and are plasticky Nissans, not a posh Lexus. I looked seriously for around 2 months and happened to find this '07 GX470, at 135k, around 180 miles from home. I contacted the owner within 20 minutes of it being posted on Cargurus and took off a day from work to get it later in the week. Ended up paying $10,700 in September of 2020, with it having a fresh timing belt/water pump/fluids, brand new tires, new rotors and pads on all 4 corners, new rear shocks, LED lights inside, brand new Depo headlights, and a Phoenix PX6 already installed. The bad was that it had been smoked in (and masked fairly well - now the smell is all but gone after some ozone treatments and a thorough clean), the underside has quite a bit of surface rust, the dash is cracked, it had whimpy tires, and the infamous exhaust manifold ticks.

Regarding the name, we live in the Ozarks in southeastern Missouri, and spend a lot of time outdoors. Most of it hiking, cycling, camping, and canoeing, but definitely some hunting and off-roading. On the maiden camping voyage with the Lexus it was christened the "Rednexus" as a few buddies and I enjoyed a campsite on a gravel bar along the Current River with an awesome campfire and a cooler of cheap beer.

Right before I purchased her:

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Taking my son on a off-roading trip along the Black River, after putting on a set of 265-70-17 Wildpeaks:
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Joined
Dec 14, 2020
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Missouri
Scored a set of bronze Vors VE37s for $500 shipped off eBay (mounted just once). Also installed Laminx yellow foglight covers. Other mods (not pictured) include a set of ARB skidplates, an aFe cold air intake, and plastidipping the grille and rear emblems. Regular maintenance included changing the diff, transfer case, and transmission fluid, replacing the starter (which took two days), and installing a SAIS bypass. All other fluids were still very fresh and the spark plugs also looked recent.

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Joined
Dec 14, 2020
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Missouri
Which leads us to today's project. Doug Thorley long tube headers (the short tubes are out-of-stock for several months) to fix the exhaust leak. Right now the GX sounds terrible at part throttle (until the intake starts to growl). I spent around 2 hours this evening pulling the OEM heat shields (almost every bolt broke off) and jacking up the motor. All other bolts/studs are soaking in PB Blaster overnight. Hopefully the long tubes are in by tomorrow evening.

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Joined
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Header replacement turned into a nightmare. All of the exhaust studs/nuts required a few hundred foot pounds to remove. This was no problem for most of them, but I ended up with one with a rounded nut on both sides, for the nuts that had a very difficult angle to remove (easy to round a nut applying ~200 ft lbs with a breaker bar through a string of wobble extensions and a U-joint). I've already tried bolt extractors and welding nuts on the studs (which kept breaking the bolts as there is only room to weld a 17mm nut to the stud, which is too small). I tried using an impact too, but the impact effect was greatly reduced through the string of extensions, and it really didn't work. I'll be cutting off these problem nuts flush with the manifold, pulling it, welding a big nut the the protruding stud, and trying to pull them out. If that fails I'm going to drive with with 7/8 studs on each side.....the DT headers have a 5/16" flange so I think they'd be OK missing a stud on both side.

If anyone else attempts this I found that pulling the sway bar, jacking up the motor on both sides, and removing the DS fender liner helps. Hopefully this ends with a succesfull completion.
 
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The end of Day 2 header update is below. This upgrade is not for the faint of heart. I've been wrenching for over 20 years, this has been the worst job, period. I've re-ringed Subaru EJ25s, done struts/brakes/etc on multiple vehicles, timing belts, adjusted valve lash, replaced cylinder heads, engine pulls and replacements, but nothing compares to this. Technically, it's easy (just bolts), but every bolt is in the worst possible place and they are easy to strip. The best option would be to find a shop that has done this before (which does not exist in my rural area) and pay them to do it. It's possible for a DIY, just hard and time consuming.

1. Removed the old headers by grinding off the rounded nuts very, very slowly with a Dremel grinding wheel and a flexible attachment. It took around 20 minutes per side (and just 1.5 grinding wheels total).
2. The studs easily came out after welding on a 7/8" I.D. nut. I found the trick is to use a nut much larger than the stud, so the weld can wrap around the stud and cover the top. They only took ~30 ft lbs to remove (probably because they had gotten red hot by welding).
3. Do buy Fel-Pro exhaust manifold gaskets. They are made in Japan and exactly the same as the OEM gaskets - must be from the same factory.
4. Don't buy Fel-Pro exhaust studs. The nuts are a M10x1.25 thread (like OEM) but a 5/8" SAE head! Never have I encountered a mixed metric/SAE nut before, what a crazy product. I have hardly any SAE tools and had to buy several sockets and wrenches to get things in.
5. It took around 90 min per side to tighten things up, and there ended up being 1 lower bolt per side that could not be tightened without removing the motor mounts from the block. I'm just going to run it as-is.
6. To-do list for tomorrow is to bolt the headers to the Y-pipe, install the rear O2 sensor spaces, re-install the sway bar, and take it for a spin.
 
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I cannot wait to hear it. Hopefully it'll be worth all this trouble.
I'll get another video of it running tomorrow and revving before I bolt up the Y-pipes. Either way it'll be better than the farm-truck like exhaust tick it had before!

In hindsight things would have been much easier if I had 1) ground down the hard-to-get studs to allow the use of a shallow socket, 2) used OEM Toyota replacement studs, and 3) pulled off the motor mounts on both sides. I could see how this job could cost $2K easily in labor for a shop to do it.
 
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I'll get another video of it running tomorrow and revving before I bolt up the Y-pipes. Either way it'll be better than the farm-truck like exhaust tick it had before!

In hindsight things would have been much easier if I had 1) ground down the hard-to-get studs to allow the use of a shallow socket, 2) used OEM Toyota replacement studs, and 3) pulled off the motor mounts on both sides. I could see how this job could cost $2K easily in labor for a shop to do it.

I'm anticipating the finished result more than anything. I want to compare it to what I did to our 470.
 
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Headers are DONE! Total install time was around 22 hours, with 4-5 hrs of that being parts and tool runs. In a perfect world this could probably be done in one day with care taken not to round any fasteners.

First impressions:

1. The ticking is GONE! Silky smooth and quiet at startup and none of that POS-like noise driving around town. Amazingly, there seem to be no other leaks in the system, but I'll re-torque next weekend as a precaution.
2. Big power gains from around 2500-4000 rpm. The GX will now put you back in the seat at a part throttle downshift. Definitely pulls a bit harder from 4000 rpm to redline, but the midrange gains are huge. Worthy upgrade just for the power.
3. Exhaust sound is about the same as before, but maybe 5% louder. No change in tone. @MrTorgue, I'd post a video but you'd just hear the cold air intake! The rest of the system behind the headers is still stock, but will get upgraded eventually.

Overall, solid upgrade. Had I been smarter it would have been easier, but live and learn!
 
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What intake are you running?
aFe Power. Has a great sound to it, the GX also seemed to pick up a small amount of power (but not much). Worth it for the sound and reusable air filter. Be advised it is kind of difficult to seal at the throttle body and I had vacuum leaks until I adjusted the couplings just right.
 
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aFe Power. Has a great sound to it, the GX also seemed to pick up a small amount of power (but not much). Worth it for the sound and reusable air filter. Be advised it is kind of difficult to seal at the throttle body and I had vacuum leaks until I adjusted the couplings just right.
I had that intake on my Charger project, they are great. Thinking about getting it for the GX’s.

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I had that intake on my Charger project, they are great. Thinking about getting it for the GX’s.

You'd like it for sure. aFe stuff is really high-quality. Love the growl when getting into the throttle (and my kids love it too). It's also nice that the GX makes almost no noise around town and when cruising, but really opens up under throttle. Adding the pre-filter sock to keep bugs/grass out of the filter is also the good idea (as that stuff seems impossible to remove once embedded in the filter pleats). Also, the filter box doesn't' quite line up with the inner fender (it's probably designed for a V8 T4R), so I added some adhesive-backed foam to provide a seal of sorts.
 
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You'd like it for sure. aFe stuff is really high-quality. Love the growl when getting into the throttle (and my kids love it too). It's also nice that the GX makes almost no noise around town and when cruising, but really opens up under throttle. Adding the pre-filter sock to keep bugs/grass out of the filter is also the good idea (as that stuff seems impossible to remove once embedded in the filter pleats). Also, the filter box doesn't' quite line up with the inner fender (it's probably designed for a V8 T4R), so I added some adhesive-backed foam to provide a seal of sorts.

Good stuff! I wonder if they make one for the 460?
 
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Today was rainy and dreary, so I spent some time in the shop. Unfortunately it rained all night and I had left the Rednexus in the driveway, so it dripped on me for the first couple of hours. Lots of mud from past trips also dripped down on the floor.

The first order of business was to slice off my running boards, which had done a good job of catching lots of mud from off roading trips.

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Next I made templates for my Apex Overland 5th gen T4R rock sliders and drilled extra holes in the framerails in both sides. I drilled around 6 holes per side and each side will have 12-14 M8X1.25 bolts holding the sliders on. The 120 and 150 platforms do share multiple bolt holes, the 120 just is missing a few, so it was easy to find and drill. I used a Milwaukee step bit and a 3/8" right angle air drill. It took awhile with my small compressor but at least the bit stayed cool. These will get threads with some rivnuts; I had ordered some but they used an oddball 17/32" hole diameter (impossible to find a drill bit for....), so I ordered another set that uses a 7/16" hole instead.
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Lastly, a photo of my mostly-installed SRQ Fabrication front recovery points, painted in Farmall Red tractor paint (which I'll never use again, the fumes are noxious and it takes forever to dry). I still need to put the sway bar back on (had removed it for the header install). Also, the one bolt hole on the side of the radiator support uses and oddball M12x1.00 ultra-fine thread, which is nearly impossible to find. I found some on eBay and they are begin shipped from China; it was literally the only place I could get them. Otherwise, these recovery points are very, very beefy, and were a bargain at $120 shipped.
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May sound crazy, but what if anyone wanting to do the DT headers just yanked out the motor? You could do a rear main seal at the same time. Lots of folks are scared to pull a motor, but if you've been turning wrenches for 20 years, you know it's really not that difficult. Mostly just prep work before the extraction.
 
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May sound crazy, but what if anyone wanting to do the DT headers just yanked out the motor? You could do a rear main seal at the same time. Lots of folks are scared to pull a motor, but if you've been turning wrenches for 20 years, you know it's really not that difficult. Mostly just prep work before the extraction.
It's certainly an option. I've pulled several motors (which only takes 3 hours in a Subaru) and have an engine hoist. I haven't researched how easy or hard it is in a GX but would consider it were I to ever do this again. It all comes down to how many accessories, wiring connectors, hoses, etc have to be removed and how hard they are to get to. Also, the bellhousing and torque converter bolts could be problematic.
 
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Wrenching weekend 2/3 continued on Sunday. Tasks completed included re-tightening header bolts (several of which were a bit loose), re-installing the front sway bar and tightening down the SRQ Fabrication recovery points, fabbing a better mounting solution for the ARB front skid (as the OEM mounting holes had stripped again), and adding a set of rock lights to replace the OEM running board lights. Next weekend will include installing the sliders, installing a new OEM Class IV trailer hitch (it currently has an aftermarket Curt Class III hitch), and undercoating the entire bottom of the GX with Woolwax Black on the chassis/suspension parts and Fluid Film everywhere else (including inside the frame).

These GX's really do look better with the running boards removed:
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Rock lights at dusk. Quite a bit brighter than stock, and not too bad for $43. I fabbed the brackets out of some 1" steel flat stock and bolted them to the running board mounting holes.They were wired into the running board harness using some heat shrink connectors, with the wiring zip-tied out the way. Hopefully these hold up.
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