Builds "Rednexus" - 2007 GX470 Build and Fabrication Thread (4 Viewers)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

how does the Hayden work with the CSF? Or are you not using the trans portion on the CSF?
Curious how the Hayden will help keep the trans from not heating up enough?
The setup works in the same way the OEM cooler setup does, with the trans fluid going into the radiator and then into the aux cooler before going back to the transmission. The only difference is that the radiator and the trans cooler should each have more cooling capacity, and the Hayden 679 has a low-temp bypass where fluid only goes through the top row of the cooler during cold temperatures (my rig would over-cool in the winter with the 678 - trans temps of like 120F - which are too low).

With my old setup (OEM radiator and a Hayden 678), my trans got hot-ish (around 225F) on some extended 4Lo climbs out in CO, and my engine got to around 205F. It was only ~50-60F outside during these climbs. If I had been in the desert with the AC on, I think the engine and trans might have gotten quite hot. I'm hoping this setup will work a bit better for slow-speed crawling like that.
 
Last edited:
Ok that makes total sense. Had I thought about it for 2 seconds, im sure I could have gotten there lol - already been a loooong week at work.

Wild the temps got that warm when it was cool out!
I drove it some this winter when it was around -5F and the trans shifted quite harshly! Probably not good on the transmission, and probably part of the reason the OEM coolers on these are under-sized (Toyota probably designed them to focused on cold-weather shifting and MPG as opposed to keeping things cool on mountain climbs).

If anyone wants my old 678 it's free for the cost of shipping and a few dollars to package it.
 
If anyone wants my old 678 it's free for the cost of shipping and a few dollars to package it.
If only I hadn't already ordered one and don't want to deal with the hassle of returning it...
 
So I've put 200 miles on the gears so far and have some more feedback:

- The rig rips. It revs quicker and puts you back in the seat harder. Overall the 2UZ feels much happier. It certainly had plenty of power before, but now it just feels even better :).
- It's definitely more buzzy on the highway. 75 mph is about 2,550 rpm. I think it was maybe 2,200 rpm or so with 3.73s. As a result, it rarely downshifts pulling hills (and our highways around here have lots of steep hills). Fuel economy doesn't seem to have taken a huge hit, but I'll need more data to confirm. I'm confident it will tow drastically better.
- The ECGS break-in recommendations are very, very conservative. I think it's a CYA in case they set one up too tight and it runs hot. I'm checking my diffs with a heat gun - normally the rear is 165-175F and the front is 140-150F. Today the rear got up to 183F after about 20 miles going 70-75 mph on the highway. My understanding is that these are "normal" temps for a rear axle. It's speculative, but my gears probably would have been just fine with almost no break-in period. But, I'll honor their break-in recommendations so they honor their warranty.
 
Last edited:
Moved the needle a bit more today.
20250613_174259.jpg

20250613_174311.jpg

^SDHQ billet battery terminals. These things are pricey but a work of art, and have much better positioning for attaching cable lugs than the OEM or military-style terminals. I think they'll also be great when I add a winch. I'm not 100% happy with the engine ground wire routing, but it will work.
20250613_174326.jpg

^Harrop elocker relay mounting. These are nice, sealed relays. The CAI airbox continues to be a great spot to mount things :).
20250613_174440.jpg

^Elocker switches in the custom Blue Dog Design Works panel I've had for some time. These are OTRATTW rocker switches and are actual Carling units. The Harrop switches are fugly and not labeled between front and rear.
20250613_174813.jpg

^And the new PX6! I've only had it in a box for 6 months. It was a simple R&R and everything worked perfectly upon startup - including wireless Android Auto. The OS in this is definitely improved and less buggy than my old PX6. But, I'm not having to re-download gigs and gigs of offline topo maps.
 
Moved the needle a bit more today.
View attachment 3928279
View attachment 3928278
^SDHQ billet battery terminals. These things are pricey but a work of art, and have much better positioning for attaching cable lugs than the OEM or military-style terminals. I think they'll also be great when I add a winch. I'm not 100% happy with the engine ground wire routing, but it will work.
View attachment 3928281
^Harrop elocker relay mounting. These are nice, sealed relays. The CAI airbox continues to be a great spot to mount things :).
View attachment 3928282
^Elocker switches in the custom Blue Dog Design Works panel I've had for some time. These are OTRATTW rocker switches and are actual Carling units. The Harrop switches are fugly and not labeled between front and rear.
View attachment 3928284
^And the new PX6! I've only had it in a box for 6 months. It was a simple R&R and everything worked perfectly upon startup - including wireless Android Auto. The OS in this is definitely improved and less buggy than my old PX6. But, I'm not having to re-download gigs and gigs of offline topo maps.
Their new album is fantastic!
 
Their new album is fantastic!
Figured there would be a few other fans on here :). To be honest, I hadn't listed to them much for the past 5-6 years or so (after being a big fan in the teens). The new album popped up on Spotify for me last month and has indeed been fantastic!
 
While I had the rig up on the lift I went ahead and replaced all of the rubber transmission and power steering fluid hoses (using Gates 3/8" hose and 90-degree stainless steel fittings - as OEM hoses are $100+ each for some of them). They looked OK, but we're getting ready to take the GX on a big road trip and I don't want to chance one failing. It was a bit of a PITA, so no pics.
20250621_113840.jpg

^Also installed some Ark fender liners. I previously had Yotaliners on the rig, and they were done by Year 2 (pretty dissapointed with the quality from a small shop like that - they might as well have been Amazon Chineseium liners). The Ark liners are super-strudy, thick rubber. We'll see how they hold up but they are way more robust than the Yotaliners or OEM liners when you hold them, and they fit great.
20250621_113900.jpg

^Sonoran Off Road Fabrication rear LCAs. I had a torn bushing in the OEM replacement LCAs, so I just went with these. They are 1/4" wall DOM with poly bushings, and are offset for more flex. Very nice quality as well and they fit great. I could have built some myself, but I would have needed to get a tubing notcher and spend a day getting them all cut out - so in this case, pre-made was the way to go.
20250621_124401.jpg

^Keeping the fridge cool in our camper while towing has been a challenge. Usually we run it on propane, but not infrequently it will stop working halfway through a road trip. So, we've lost full fridges of food before. We could run it on the 12V battery only, but the 50 amp-hour camper battery is borderline for a all-day pull. So, I ran a fused set of 10-ga wires from my underhood bus bar all the way to the back of the rig, and installed an Anderson connector. The camper side then has another Anderson connector (shown here) that goes straight to the camper's battery. I'm hoping we can run the fridge on 12V with most of the power coming from the alternator in the GX. While parked, it will have two AGM batteries to draw power from (both the rig and camper have their own Odyssey group 34 batteries, for 100 amp hours total). It it depletes both batteries while stopped for some reason, we have a Noco jump back in the rig at all times.
20250621_150133.jpg

^I went to remove the OEM trailer plug to fish the Anderson connector through, and it broke in half. Needless to say but no one had a GX-specific, plug-and-play new trailer plug in stock down here in the sticks. In order to get this fixed today, I ran down to the farm store and picked up a Hopkins plug for Ford/GM/Dodge trucks ($30), and spliced it into the OEM plug harness, so it will plug right into the GX body harness. I also had to modify the bracket to get this to fit - the paint is drying on it now, and I'll install it tomorrow.
 
Last edited:
20250622_164347.jpg

^First tow with the new setup! It is sooooo much better than it was before. The 4.56 gears made a big difference on acceleration, and I was able to tow with the cruise set on 65 mph (with 3.73s, even a tiny hill would have it downshifting into 3rd, so I ran it cruise-less). The Firestone bags (and Shocker hitch) feel more stable than our old WDH setup, probably due to more stiffness at the back of the rig. I think it will be possible to forget the camper is there with this setup (although I did order some 1/2" rear coil spacers to level it out a bit).
20250622_164406.jpg

^I built a Blackstone and table holder for the front of the camper (it's 16-ga 1" square tubing), and swapped the manual jack for a drill powered jack (mounted more rear-ward to allow the barn door to open more). The geometry on this was a PITA to figure out where it would hold everything, allow the camper to close/open, and be back far enough to allow the door of the GX to open. I am thinking this combined setup will save us 10 minutes each at setup and teardown (relative to storing this stuff inside the camper, and using a hand jack).
20250622_164401.jpg

^Shocker hitch. It's a 2/2-5/16" combo and allows for 4" of drop. I was skeptical on how it would do with a light trailer like this (it's rated for 12,000#), but it really does make a difference. I also ditched the annoying TrailManor safety cables for some safety chains (again, easier to deal with at setup/teardown than the coiled cables).
20250622_171359.jpg

^Last mod was welding a polished Amazon Chineseium tip on my 90-degree exhaust exit piece. I just run this when towing to keep the exhaust noise from bouncing off the front of the camper (it makes a big difference on the volume inside the rig).
 
Nice! How’s your daily driving mpgs been since the regear?
There is just around 550 miles on it so far, but I haven't really noticed a difference either way. Surprisingly interstate/highway MPG is about the same as before, but that's only been one trip. I expected the highway MPG to drop a bit as the 2UZ is spinning 2,700 RPM to pull 80 mph.
 
^Keeping the fridge cool in our camper while towing has been a challenge. Usually we run it on propane, but not infrequently it will stop working halfway through a road trip. So, we've lost full fridges of food before. We could run it on the 12V battery only, but the 50 amp-hour camper battery is borderline for a all-day pull. So, I ran a fused set of 10-ga wires from my underhood bus bar all the way to the back of the rig, and installed an Anderson connector. The camper side then has another Anderson connector (shown here) that goes straight to the camper's battery. I'm hoping we can run the fridge on 12V with most of the power coming from the alternator in the GX. While parked, it will have two AGM batteries to draw power from (both the rig and camper have their own Odyssey group 34 batteries, for 100 amp hours total). It it depletes both batteries while stopped for some reason, we have a Noco jump back in the rig at all times.

^I went to remove the OEM trailer plug to fish the Anderson connector through, and it broke in half. Needless to say but no one had a GX-specific, plug-and-play new trailer plug in stock down here in the sticks. In order to get this fixed today, I ran down to the farm store and picked up a Hopkins plug for Ford/GM/Dodge trucks ($30), and spliced it into the OEM plug harness, so it will plug right into the GX body harness. I also had to modify the bracket to get this to fit - the paint is drying on it now, and I'll install it tomorrow.
Nice to hear the towing was good!

I was actually thinking about doing something similar for 12v power to the trailer while towing. We have 2 group 24 batteries on the trailer right now. Our first pull next weekend will probably be about 2hrs and our bigger trip in a couple months will be probably closer to 3.5 hrs. Our fridge is only shore power or battery (no propane - which that slipped past me when we bought since we looked at so many models. Probably swap to a propane compatible whenever this one goes out).

I had to fandangle my 7-pin too when I got the Diode Dynamics rear hitch light.
 
The fridge still got pretty warm on my pull yesterday, so I pulled the panel off the fridge and it was only getting 10.5V DC! Probably a poor connection in the long camper wiring from the battery, to fuse panel, to the back of the fridge (the electrical system in the camper is not up to my quality preference in terms of connections :) ). So I ran a dedicated set of fused 10 ga wires from the camper battery to the fridge, and now it's getting full battery voltage at the fridge panel. We're going to run an test all day with the fridge of 12V and see how it does - temps are already going up a bit, unfortunately, so we may also a propane test.

EDIT: It's in the 90s out today and the fridge is holding steady at 35F on 12V DC! The 10-ga wiring seems to have fixed the problem, as I have a full 12.6V at the back of the fridge while it's running, relative to 12.9V at the battery (which is being charged via the camper's AC-DC charger). I'm thinking the GX should send ~13V DC to the camper battery while running via the Anderson connectors, so hopefully we have similar performance while towing.
 
Last edited:
The 10-ga wiring to the fridge seems to have totally solved the issue. We ran a test today with 1) the camper closed in 90F+ heat and in the sun, 2) the fridge on 12V DC with shore power disconnected, and 3) a gallon jug of water in the fridge that had been pre-cooled in our house fridge (to replicate some food in the fridge). We monitored fridge temps and battery voltage throughout the test, which are plotted below:
Picture1.png

Under these conditions the 50 amp-hour Odyssey AGM gives about a 4 hour runtime on the battery alone. With the GX hooked up (and not running), in theory there would be about an 8-hour runtime prior to both batteries being depleted. With the GX running and sending ~13.4 volts back to the camper, I'm confident the fridge would maintain 35F indefinitely. I did some calculations on the amp draw (based on the state of charge vs. time) and calculated the fridge was drawing around 8-12 amps DC during the test (which makes sense as the max amp draw is 15 DC per Dometic).

So @stupidchicken03 , I'd definitely suggest this mod (fused wires from your battery direct to the camper with a Anderson connector) if you are going to drive more than a few hours with the fridge on. 10 ga worked just fine for me and should be plenty large for ~12 amps DC max, even over such a long run. Your fridge is probably a bit bigger so you could go with 8 ga if you wanted. I also have a master disconnect switch on the camper battery box...the hot wires from the GX come into this so turning the disconnect "off" totally disconnects both the GX and the camper from the battery.
 
The 10-ga wiring to the fridge seems to have totally solved the issue. We ran a test today with 1) the camper closed in 90F+ heat and in the sun, 2) the fridge on 12V DC with shore power disconnected, and 3) a gallon jug of water in the fridge that had been pre-cooled in our house fridge (to replicate some food in the fridge). We monitored fridge temps and battery voltage throughout the test, which are plotted below:
View attachment 3935493
Under these conditions the 50 amp-hour Odyssey AGM gives about a 4 hour runtime on the battery alone. With the GX hooked up (and not running), in theory there would be about an 8-hour runtime prior to both batteries being depleted. With the GX running and sending ~13.4 volts back to the camper, I'm confident the fridge would maintain 35F indefinitely. I did some calculations on the amp draw (based on the state of charge vs. time) and calculated the fridge was drawing around 8-12 amps DC during the test (which makes sense as the max amp draw is 15 DC per Dometic).

So @stupidchicken03 , I'd definitely suggest this mod (fused wires from your battery direct to the camper with a Anderson connector) if you are going to drive more than a few hours with the fridge on. 10 ga worked just fine for me and should be plenty large for ~12 amps DC max, even over such a long run. Your fridge is probably a bit bigger so you could go with 8 ga if you wanted. I also have a master disconnect switch on the camper battery box...the hot wires from the GX come into this so turning the disconnect "off" totally disconnects both the GX and the camper from the battery.
Tests, data, and graphs!!! I love it!
 

Users who are viewing this thread

Back
Top Bottom