Builds "Rednexus" - 2007 GX470 Build and Fabrication Thread (2 Viewers)

[AmericanKing]

You got some great contents on this build. I appreciate the power steering rack job. I think I might try the same rack. I’m experiencing excessive steering wander at high speeds. Not safe it scared the out of me today when I hit a cross wind. Thought I was going to loose control. I’ve replaced outer tie rod, springs and struts front and rear sway bar links. That my only guess to my issue.

 

[Rednexus]

You got some great contents on this build. I appreciate the power steering rack job. I think I might try the same rack. I’m experiencing excessive steering wander at high speeds. Not safe it scared the out of me today when I hit a cross wind. Thought I was going to loose control. I’ve replaced outer tie rod, springs and struts front and rear sway bar links. That my only guess to my issue.

Thank you! It's been a fun journey/money pit over the past 18 months of GX ownership!

If you have someone sit in the seat and move the wheel back and forth with the GX stopped, the entire rack will also move back and forth if the bushings are shot. That is how I was able to diagnose mine - the rack had literally 1/2 to 3/4" of side-to-side play in it. Something inside the rack could also be messed up, which could cause that too.

 

[Rednexus]

Added onboard air today. I used a Smittybilt 2781. I fabricated the tray out of a 5-inch wide piece of 10-ga steel and the feet out of some scrap pieces of 1/8" steel, using a cardboard template. Unfortunately I did not have my flux core voltage/wire feed settings quite right and got a ton of splatter, but no one will see it anyway, so I didn't bother grinding it. It holds the compressor really well.

For the compressor I modified it quite a bit by removing the "handle", threading a M12x1.00 to 1/4" NPT adapter into the cylinder head, and then adding a 4-way NPT block with a pressure switch, safety valve, and QD connector. The actual tires get aired up using a 25' flex coil hose with a inflator and gauge (all 1/4" NPT as well). I wired the compressor directly to the battery using 10-ga wire and a 40-amp circuit breaker.

On a test run I inflated my 32" tire from 18 to 32 psi in 1 min 15 seconds, which is about twice as fast as my handheld compressor. I still have a small air leak where the adapter is threaded into the cylinder head, so I hope I can get a bit more out of it. The Smittybilt is a decent compressor for the money, but it is Chinese....if I was wheeling a lot I'd pony up for a ARB twin. This whole set up with the compressor, bracket, wiring, fittings, etc cost me around $300.

 

[NJGX470]

Added onboard air today. I used a Smittybilt 2781. I fabricated the tray out of a 5-inch wide piece of 10-ga steel and the feet out of some scrap pieces of 1/8" steel, using a cardboard template. Unfortunately I did not have my flux core voltage/wire feed settings quite right and got a ton of splatter, but no one will see it anyway, so I didn't bother grinding it. It holds the compressor really well.

For the compressor I modified it quite a bit by removing the "handle", threading a M12x1.00 to 1/4" NPT adapter into the cylinder head, and then adding a 4-way NPT block with a pressure switch, safety valve, and QD connector. The actual tires get aired up using a 25' flex coil hose with a inflator and gauge (all 1/4" NPT as well). I wired the compressor directly to the battery using 10-ga wire and a 40-amp circuit breaker.

On a test run I inflated my 32" tire from 18 to 32 psi in 1 min 15 seconds, which is about twice as fast as my handheld compressor. I still have a small air leak where the adapter is threaded into the cylinder head, so I hope I can get a bit more out of it. The Smittybilt is a decent compressor for the money, but it is Chinese....if I was wheeling a lot I'd pony up for a ARB twin. This whole set up with the compressor, bracket, wiring, fittings, etc cost me around $300.
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Good job on this. Doesn't look like a bad setup at all for $300. About a minute per tire for airing back up is not long at all.

 

[Rednexus]

Good job on this. Doesn't look like a bad setup at all for $300. About a minute per tire for airing back up is not long at all.

Thanks! It seems to be maxing out at 110 psi relative to the rated 150 psi so i think it might go faster after i fix the leak at the head. Getting some pneumatic thread sealant today.

 

[HomersCanyonero]

I see where you cut the handle and hose on the air compressor. My goal is to keep the air compressor stock, but use the Japan quick connect adaptors to convert to the industrial quick connects that everyone else uses.

This allows me to buy any of the aftermarket air hoses and gauges from arb, flexzilla, and others.

And maybe just add a bracket in the engine bay to store the air compressor, but not connect it to battery.

 

[Rednexus]

I was able to un-bolt the handle and remove the factory pipe from the head, then install the M12x1.00 to 1/4" NPT adapter from there. So the rest of my setup is all normal 1/4" NPT - I used a flex hose and tire inflator with a gauge from Harbor Freight. This was partially due to where I mounted it, so the hose would not interfere with the strut on the hood, but also allowed me to add in a pressure shut-off switch. If you mount it lower or somewhere else you can keep more of the factory compressor parts.

There are a couple of problems with this compressor, including that it gets HOT. This past weekend it got so hot that a small hole melted in my flex hose when I was blowing up an inflatable kayak. The QD was too hot to touch as well. I've modified the setup a bit to account for that and will post a picture in a few days. The other is the wiring - it actually has a wire nut connecting the battery leads to the compressor motor (inside the compressor, under the switch area). I wasn't comfortable with a wire nut in an area that might get wet so I removed it and replaced it with a 10 ga heat shrink butt splice.

If you do want to wire it to the battery, it's not particular difficult and is probably safer that using the provided cables, as you get a better connection and have less of a chance of shorting something out when hooking/unhooking. I added the 40-amp circuit breaker on the positive side, a few inches past the battery, just to keep my GX from burning down if there is an electrical issue between the battery and compressor.

 

[HomersCanyonero]

Thanks for the info. Most likely I won’t hardwire to battery.

I’m thinking a tray to store it in the engine bay, but DRANGED mentioned dust…I might just pack it back in the bag.

 

[Rednexus]

Photos of my tweaks (final maybe?) to the air setup are listed below. Due to the QD chuck getting super hot (probably 150F+), I switched the setup to a 1/4" NPT pipe nipple and a MUSA Goodyear air hose (rated to 190F). I then ran the hose to the PS inner fender and made a simple bracket to accept a 1/4" NPT bulkhead fitting and relocated the QD fitting to there. The bracket is attached with M6 bolts to two rivnuts I installed in the PS inner fender. The QD should stay cooler and keep from cooking any more nylon flex hoses.

 

[HomersCanyonero]

That looks very clean. Nice job fabbing your own brackets.

 

[Rednexus]

Just did a test air-up with all 4 tires, from 18 to 32 psi. 5 min, 11 sec, from the time I turned the compressor on until Tire 4 was filled. Overall this is WAY faster than my 20V cordless setup, which was usually 20+ minutes. At this rate, I'll need a total of 24 air-ups to recover the 6 or so hours I spent installing this system . It was always kind of annoying to have to pace around the outside of my GX at the end of the trail while airing up, especially when I had my family with me. The 20V system also had some other serious limitations, like having to make sure the battery was charged before leaving, and being limited to a single air-up event per battery charge (not ideal if hopping on and off of multiple trails per day, given several hours was required to charge the battery via the 110V outlet in the rear of the GX).

 

[Rednexus]

Good (albeit expensive) parts arrived today. It may be a few weeks until i can install these, but I'm really looking forward to a more responsive transmission that doesn't gear hunt.

 

[ArBrnSnpr]

Very cool!
Are you planning to do the install?
Post your impressions if you don't mind.

 

[Rednexus]

Very cool!
Are you planning to do the install?
Post your impressions if you don't mind.

Yes, I am going to DIY the install (it does not look too bad). I'll post some pics of the process and my thoughts on the improvements and if it's worth the nearly $2K price tag.

I'm currently thinking on where to mount the TC lockup switch - I'm thinking of removing the aux jack plug in the center console (which I never use), putting the DAC switch there, then putting the TC lockup switch where the DAC is now (the TC lockup switch appears to be exactly the same size as the OEM switches).

 

[kody472]

That's awesome! Let us know how it goes. I'd like to do something with mine to help with the shifting while pulling the camper as well. I've even debating on selling the GX for an LX, but I'd rather keep what I have (it's paid for and I have it pretty close to how I want it).

 

[Maxacceleration]

How about shifting manually? (not trying to persuade Rednexus not to do trans upgrades) Just like a manual transmission, you pick your gear.
An auto will always shift back & forth to a point. Or go to top gear with no load. Happens in any auto car/truck I have ever owned.
I shift my auto manually to hold a proper gear/rpm's for the given grade/load.
Sometimes I just have to back off and hold the gear it will pull, and give up on the mph I want to/hope to attain.
These are a lowish power V8, but to me, they have an amazing transmission overall.

 

[Rednexus]

How about shifting manually? (not trying to persuade Rednexus not to do trans upgrades) Just like a manual transmission, you pick your gear.
An auto will always shift back & forth to a point. Or go to top gear with no load. Happens in any auto car/truck I have ever owned.
I shift my auto manually to hold a proper gear/rpm's for the given grade/load.
Sometimes I just have to back off and hold the gear it will pull, and give up on the mph I want to/hope to attain.
These are a lowish power V8, but to me, they have an amazing transmission overall.

I shift it manually all the time, especially when towing. The A750F is certainly a bulletproof transmission, but the gear hunting (towing or not) is pretty annoying IMO. We have a lot of shorter steep hills here, and it's not uncommon for mine (when in D and unloaded) to go 5th/4th/5th/4th/5th on a single hill, with a few cycles of the TC locking and unlocking as well. The other issues these have is that the TC will not lock below 4th gear. So on a steep hill where I need 3rd gear when pulling our camper, the transmission gets a lot of heat. I can't see taking our camper into any real mountains due to that - when we took it out west last summer without a camper, it got up to 220F a couple of times in 3rd gear.

I also find the overall trans tuning, in regards to it holding a gear (it likes to shift into 2nd way too soon) and downshifting (it's laggy to downshift at part throttle) pretty annoying. From driving more modern automatics in other trucks and cars, the A750F seems overall pretty sluggish/unresponsive and with soft shifts.

Shifting manually can alleviate some of that, but it's still left with the soft shifts and inability to lock up below below 4th gear. I would generally prefer a better tuned auto that doesn't require manual shifting so often (at that point I'd rather drive an actual manual transmission - which I badly wish was a possibility in a GX ).

 

[Maxacceleration]

I'm following you Rednexus. I did not see the GX470 listed in Wholesale Automatics?
So you using the heavy duty valve body with the TC lock up for 1st gear lock up also?
It does look intriguing, and for myself, for the 295 tires with stock gearing I am running.
I would be curious on how hard the improved set up shifts for you. I'll stay tuned...

 

[Rednexus]

I'm following you Rednexus. I did not see the GX470 listed in Wholesale Automatics?
So you using the heavy duty valve body with the TC lock up for 1st gear lock up also?
It does look intriguing, and for myself, for the 295 tires with stock gearing I am running.
I would be curious on how hard the improved set up shifts for you. I'll stay tuned...

I purchased the kit from Cruiser Brothers (Home - CruiserBrothers - https://cruiserbrothers.com/), who is the only US distributor. It's not listed on their website but they had the kit in stock. I would presume the kit is the same as the Wholesale Automatics kit for a 120 Prado with the 4.0 and A750F. It is the Stage 1 Nomad valve body (for towing/off road), with the override lockup switch that allows lock up in any gear. You can get the switch without the valve body, but it will only lock up in 2-5th. I really just want the lockup for 2-5 when towing our camper up long grades, but I wanted the valve body anyway to firm up the shifts and overall responsiveness.

I might get this in next weekend, it not it will be later in June. After the install I'll report back and maybe post a video of the shifts. It seems that only a couple other forum members have actually installed these so far.

 

[aztoytec]

I purchased the kit from Cruiser Brothers (Home - CruiserBrothers - https://cruiserbrothers.com/), who is the only US distributor. It's not listed on their website but they had the kit in stock. I would presume the kit is the same as the Wholesale Automatics kit for a 120 Prado with the 4.0 and A750F. It is the Stage 1 Nomad valve body (for towing/off road), with the override lockup switch that allows lock up in any gear. You can get the switch without the valve body, but it will only lock up in 2-5th. I really just want the lockup for 2-5 when towing our camper up long grades, but I wanted the valve body anyway to firm up the shifts and overall responsiveness.

I might get this in next weekend, it not it will be later in June. After the install I'll report back and maybe post a video of the shifts. It seems that only a couple other forum members have actually installed these so far

Really curious how much this will help the trans temperature especially while towing.