My Issues - Roof Rack Noise, Bad Hood, Fuel Capacity, Rear Dif Lock, Cruise, Brake and Brake System Noises

[Jabber]

I've had my GX550 OT+ for a couple months. It has 5000 miles on it now and 3000 of that is on the highway. There are a few things that I saw that In My Opinion are real design issues. I read the forums and see that other have seen them too. The first 4 were not apparent on the test drive because if any dealer lets you test drive one of these its a short loop around the block at low speeds. They all became apparent to me as soon as I had some time on the highway. So I'll start with those;

1) Wind Noise in the Cabin - Its unbelievably bad with the OT+ with a roof rack. I had it on highway with limits of 75mph and drove 80-85mph. You have to yell to talk to someone inside the vehicle. The sort term fix - take the roof rack off. I did it myself and once it's off the change is huge. They need to redesign the leading edge of that rack. It's not right as it is and we shouldn't have to remove it to have a reasonably quiet cabin at highway speeds.

2) Hood Flex - At highway speeds the hood flexes and bends a lot. The faster you go and the winder it is, the more you will see. The combination of flexing and reflections shifting around from the hood because of the flexing can be pretty distracting. I took a Lexus mechanic out today to show him today. That hood is not reinforced properly. The center of the hood looks like it bows up an inch or more, but you can even see it to a lesser degree in the ridges on the sides of the hood.

3) Fuel Tank Capacity - On the highway at 75-85 mph I was getting 15.4 mph. Less driving around home. A full tank shows me a range of 274 miles. This is a low range, really low for a vehicle that is designed for off road. I feel like that made the tank for the more fuel efficient Toyota 4 and never considered if the tank would be sufficient for the Lexus 6. 274 isn't even that good for an electric car anymore, so I can't understand how this was missed.

4) Cruise Control Calibration - I've been driving highways with adaptive cruise control in my car since 2002. The Lexus system works pretty darn well and is fantastic if you drive on the highways. Even the traffic jam assist (which uses the same system in stop and go traffic) is really nice. Whatever speed I set it at however, the car settles (when the road is open and the car is uninhibited from running to the limit) at 1 mph lower than the speed I set. I've played with it at different speeds, accelreting above the set speed and having it settle back down to the setting, changing the speed using the +/- buttons on the steering wheel, changing the safety gap up/down. It doesn't matter, it settles back to 1 mph less than what I've set.

Ok, those are my highway design issues. The first 3 are design issues. The 4th I am assuming can be corrected with a callibration. There are a few other issues that I am having them look at. They are;

5) Rear Differential Lock doesn't engage - I have taken it off the road, but it was light use on some frozen farm land. I am taking out into the desert next month. I have tried everything in the car just to know how it works. I've read the manual too. The one thing that just never worked was the Rear Differential Lock. I flashes and beeps but never locks. I showed the Lexus mechanic and they are looking at it now.

6) Brake Noise - The brakes squeal, mostly in reverse and after sitting overnight. I think this is a known issue and may have a fix already.

7) Screech when shifting out of Drive to Park - I understand that this noise from the engine compartment is the brake system and when I dropped it off for my issues today, I was getting the feeling that they were telling me that its normal and occurs on all Lexus. It's not normal for any other high car I've owned. At first I was causing the noise by slighting turning the tires on the epoxy finished garage floors as I was putting into park. That's what is kind of sounds like. Then I was worried it was coming from the turbos as they were spooling down (which would be really bad). Is this really something I have to get used to hearing when I park the vehicle?

I still really love the vehicle and can wait to get it from the snow of Chicago to the desert of Pheonix. I am hoping some of my issues have solutions that Lexus will be offering. If anyone knows of fixes coming, I would love to hear about them so I can "help" the dealer get them for my GX OT+.

 

[incognito.gx]

Rear diff only locks in 4Low with the center diff already locked

 

[Jabber]

Rear diff only locks in 4Low with the center diff already locked

TY. I'll try that sequence when I get it back. Is that sequence described in the owners manual and I missed it?

 

[jupabalo98]

I just received my OT last week. And yes they fuel tank capacity is a nuisance. Mine doesn’t seem to be too loud on the hwy it’s definitely a lot quieter than my 21 IS350, and we don’t have the newest / best hwys in the country here in Florida. That squeal when going into park happened also on my 21 Is350 and it’s from the parking break. Still waiting to see if my GX gets the same fate (it only has 568miles on it ). I also have the same issue with the cruise control I think it has something to do with target speed set by the cruise control and the vehicle sensing that speed differently in the cruise control computer than the one that is displayed, I’ve seen it happen more when there’s very windy conditions. I’ll have to check on the read diff engaging on mine. I haven’t paid much attention to it since I haven’t had it for too long.

Hope you’re overall enjoying your GX !!

 

[Jabber]

I just received my OT last week. And yes they fuel tank capacity is a nuisance. Mine doesn’t seem to be too loud on the hwy it’s definitely a lot quieter than my 21 IS350, and we don’t have the newest / best hwys in the country here in Florida. That squeal when going into park happened also on my 21 Is350 and it’s from the parking break. Still waiting to see if my GX gets the same fate (it only has 568miles on it ). I also have the same issue with the cruise control I think it has something to do with target speed set by the cruise control and the vehicle sensing that speed differently in the cruise control computer than the one that is displayed, I’ve seen it happen more when there’s very windy conditions. I’ll have to check on the read diff engaging on mine. I haven’t paid much attention to it since I haven’t had it for too long.

Hope you’re overall enjoying your GX !!

Thanks for the reply. See the other response I got on the rear dif lock. I checked the manual and it's not clear, but I think you need to 1st put it in 4 Low, then lock the center differential, then lock the rear differential. I gotta get it back from service to give that a try but it does make sense.

 

[Bluegill]

The squeal when you put it in park in the parking brake automatically engaging. You can turn this off in the maze of on-screen vehicle settings. There is a parking brake button on the center console so you can manually set the parking brake. That being said, it is a good practice to always set the parking brake when you park. I would prefer a manual handle in the cabin to yank up but those times have passed.

 

[Jabber]

The squeal when you put it in park in the parking brake automatically engaging. You can turn this off in the maze of on-screen vehicle settings. There is a parking brake button on the center console so you can manually set the parking brake. That being said, it is a good practice to always set the parking brake when you park. I would prefer a manual handle in the cabin to yank up but those times have passed.

Thank you. Yea, the dealer was telling me it was the brake system. The parking break makes sense in the situation of shifting to park. They suggested it's "normal". I'd rather have it on so I guess i'll get used to it, but don't think it should be so noticeable.

 

[Bluegill]

I agree, the actuation of the parking brake is incredibly loud and annoying. You'd think the engineers would have installed the first one, actuated the solenoid or whatever the internal mechanism consists of, heard the squawk, and then said, "This won't do at all." But of course that's not really how it works so it made it into production. Just like the fluttering hood and brakes squealing in reverse.

 

[Jabber]

Exactly, Lexus is a luxury brand. The mechanics at the dealer say it's normal and the noise happens on all Lexus models with that parking brake system turned on. Lexus engineers must think it's okay, but none of the other luxury brands I've owned have had a similar issue (nor do I believe they would find it okay if they did).

 

[incognito.gx]

E-brakes make noise. Wtf ya’ll moaning about?

 

[happykamper]

First comment but have been reading/lurking on here, iH8mud, and various Reddit subs and as someone who has been on a waitlist for a 550 OT+ for the last 10 months I am becoming less and less enthused by the owner feedback I am seeing. These types of issues should not exist on what's supposed to be a luxury vehicle. I understand it has made a shift in focus to embrace it's off road capabilities but it's still supposed to be a Lexus, not a Ford or GM! Hopefully this is just first model year woes that will be corrected for 2025.

 

[Euler]

First comment but have been reading/lurking on here, iH8mud, and various Reddit subs and as someone who has been on a waitlist for a 550 OT+ for the last 10 months I am becoming less and less enthused by the owner feedback I am seeing. These types of issues should not exist on what's supposed to be a luxury vehicle. I understand it has made a shift in focus to embrace it's off road capabilities but it's still supposed to be a Lexus, not a Ford or GM! Hopefully this is just first model year woes that will be corrected for 2025.

You make a great point - this is supposed to be a Lexus. Have had a bunch of minor issues with my Lux + such as navigation screen with grey bar across top and not shifting from day to night mode in addition to dead key fobs. Not huge issues but this I supposed to be a luxury brand and a brand that champions quality manufacturing. Have had GS and previous GX and both had impeccable build quality. I am amazed how little concern Lexus has shown in addressing some of these quality issues and can assure you BMW Audi MB are taking note. It takes a long time to build a reputation and very little to ruin it. On the positive side - everyone who sees says it looks amazing - seems design was more important than build for 2024.

 

[Bluegill]

The parking brake or emergency brake noise is not an "issue" as in a "problem." It's just a bit odd and slightly annoying every time you shift into park, the truck make a very loud and sharp squawk noise.

 

[Jabber]

E-brakes make noise. Wtf ya’ll moaning about?

I was moaning about the moaning

 

[Bluegill]

I was squealing about the squawking.

Or maybe I was squawking about the squealing.

 

[rnr]

Not sure you can complain about wind noise on the highway with a legit roof rack. It just comes with the package. Had some old ones back in the day with a true wind deflector attached to the front, and they were quieter, but the new flat, square racks always make noise. If you have a sunroof, close the shade, will help some. Not sure why the parking brake goes on every time you put it in park . . . it’s not a manual. Might reprogram b/c that tends to wear out parts. On my ‘17 Land Cruiser, the fact the door locks lock each time in drive and unlock in Park wore them out after 3 years. My cruise control always has the car drive one MPH slower than it’s set as well. Of course, I’m going 85, so maybe it’s good. Most annoying thing is the fuel range on these. LCs always had bad range, and the GX is just as bad. Just uncalled for in a 2025 vehicle getting about 16.4 mpg. Getting less than 300 miles of range is redonkulous.

 

[Jabber]

I've had my GX550 OT+ for a couple months. It has 5000 miles on it now and 3000 of that is on the highway. There are a few things that I saw that In My Opinion are real design issues. I read the forums and see that other have seen them too. The first 4 were not apparent on the test drive because if any dealer lets you test drive one of these its a short loop around the block at low speeds. They all became apparent to me as soon as I had some time on the highway. So I'll start with those;

1) Wind Noise in the Cabin - Its unbelievably bad with the OT+ with a roof rack. I had it on highway with limits of 75mph and drove 80-85mph. You have to yell to talk to someone inside the vehicle. The sort term fix - take the roof rack off. I did it myself and once it's off the change is huge. They need to redesign the leading edge of that rack. It's not right as it is and we shouldn't have to remove it to have a reasonably quiet cabin at highway speeds.

2) Hood Flex - At highway speeds the hood flexes and bends a lot. The faster you go and the winder it is, the more you will see. The combination of flexing and reflections shifting around from the hood because of the flexing can be pretty distracting. I took a Lexus mechanic out today to show him today. That hood is not reinforced properly. The center of the hood looks like it bows up an inch or more, but you can even see it to a lesser degree in the ridges on the sides of the hood.

3) Fuel Tank Capacity - On the highway at 75-85 mph I was getting 15.4 mph. Less driving around home. A full tank shows me a range of 274 miles. This is a low range, really low for a vehicle that is designed for off road. I feel like that made the tank for the more fuel efficient Toyota 4 and never considered if the tank would be sufficient for the Lexus 6. 274 isn't even that good for an electric car anymore, so I can't understand how this was missed.

4) Cruise Control Calibration - I've been driving highways with adaptive cruise control in my car since 2002. The Lexus system works pretty darn well and is fantastic if you drive on the highways. Even the traffic jam assist (which uses the same system in stop and go traffic) is really nice. Whatever speed I set it at however, the car settles (when the road is open and the car is uninhibited from running to the limit) at 1 mph lower than the speed I set. I've played with it at different speeds, accelreting above the set speed and having it settle back down to the setting, changing the speed using the +/- buttons on the steering wheel, changing the safety gap up/down. It doesn't matter, it settles back to 1 mph less than what I've set.

Ok, those are my highway design issues. The first 3 are design issues. The 4th I am assuming can be corrected with a callibration. There are a few other issues that I am having them look at. They are;

5) Rear Differential Lock doesn't engage - I have taken it off the road, but it was light use on some frozen farm land. I am taking out into the desert next month. I have tried everything in the car just to know how it works. I've read the manual too. The one thing that just never worked was the Rear Differential Lock. I flashes and beeps but never locks. I showed the Lexus mechanic and they are looking at it now.

6) Brake Noise - The brakes squeal, mostly in reverse and after sitting overnight. I think this is a known issue and may have a fix already.

7) Screech when shifting out of Drive to Park - I understand that this noise from the engine compartment is the brake system and when I dropped it off for my issues today, I was getting the feeling that they were telling me that its normal and occurs on all Lexus. It's not normal for any other high car I've owned. At first I was causing the noise by slighting turning the tires on the epoxy finished garage floors as I was putting into park. That's what is kind of sounds like. Then I was worried it was coming from the turbos as they were spooling down (which would be really bad). Is this really something I have to get used to hearing when I park the vehicle?

I still really love the vehicle and can wait to get it from the snow of Chicago to the desert of Pheonix. I am hoping some of my issues have solutions that Lexus will be offering. If anyone knows of fixes coming, I would love to hear about them so I can "help" the dealer get them for my GX OT+.

Ok - I got it back from the dealer. They looked at my concerns.

1) Roof Rack Wind Noise - They acknowledge the issue and will contact me later.

2) Hood Flex - They acknowledge the issue and refit the hood. I haven't driven it enough to evaluate the fix.

3) Fuel Tank Capacity - Nothing to offer on this, but that's what I expected.

4) Cruise Control - They wrote up that they couldn't replicate, but I took a mechanic on the test drive and showed him, so I will have to touch base with them again.

5) Rear Dif Lock - It works fine. Another blogger told me that there is a sequence you must follow to engage it (1-put in 4 low, 2-push on center dif lock, 3-push on rear dif lock). That sequence is not in the owners manual, but that does the trick.

6) Brake Noise - They acknowledge the issue, and if I understand, are delivering new vehicles with the fix. They will fix this with new brakes and rotors. Mine are on order, so I am waiting for this to be complete.

7) Squealing Noise When Shifting to Park - This is the parking brake system which has a setting to engage automatically when put into park. They turned that setting off so that it no longer engages automatically (another blogger suggested that too - TY). While that eliminates the noise, I stand by that it shouldn't make that much noise if the option is on, but I am fine with that resolution and will leave it off and engage the parking brake myself when I think I need it.

I'll update again later on "My Issues".

Still love the car and I am happy with Lexus initial response to the issues.

 

[Jabber]

Not sure you can complain about wind noise on the highway with a legit roof rack. It just comes with the package. Had some old ones back in the day with a true wind deflector attached to the front, and they were quieter, but the new flat, square racks always make noise. If you have a sunroof, close the shade, will help some. Not sure why the parking brake goes on every time you put it in park . . . it’s not a manual. Might reprogram b/c that tends to wear out parts. On my ‘17 Land Cruiser, the fact the door locks lock each time in drive and unlock in Park wore them out after 3 years. My cruise control always has the car drive one MPH slower than it’s set as well. Of course, I’m going 85, so maybe it’s good. Most annoying thing is the fuel range on these. LCs always had bad range, and the GX is just as bad. Just uncalled for in a 2025 vehicle getting about 16.4 mpg. Getting less than 300 miles of range is redonkulous.

Thanks for the response. I just got it back from the dealer and gave an update. The fuel tank capacity is the one that I don't expect Lexus to be able to acknowledge because it works fine, but is just the wrong size for the Lexus turbo 6. I drove mine for 2 full days on the highway (before I removed the roof rack). I got 15.4 mph on the highway driving 85 mph. Full tank range says 274 which means you fill up every 3 hours. IMO - that tank ought to be at least 6 gallons larger.

 

[Bluegill]

A couple comments regarding the parking brake....

Automatic transmissions are equipped with a parking pawl which is a metal pin that locks the transmission's output shaft, thereby preventing the transmission gears from turning, thereby preventing the wheels from turning.

The parking pawl is considered a backup to the parking brake. You really shouldn't rely solely on the parking pawl keeping your 5,500 lb truck from moving. When you look at a scene such as cars and trucks parallel parked on steep inclines like you see in San Francisco, it should scare the shit out of you knowing that the vast majority of them probably have no parking brakes engaged. But at least it's not like the ground would ever shake in San Fran and put extra stress on all those parking pawls....LOL.

The practice you should actually observe is to drive to your destination, parking spot, etc., put the truck in (edit - neutral not DRIVE), keep your foot on the brake pedal, activate the parking brake, then shift into park. This puts the task of keeping the truck from moving primarily on the parking brake with the parking pawl as backup. This keeps the stress off the transmission components.

I don't know if the GX550's fancy automatic parking brake does anything special, such as making the parking brake the primary and the pawl the secondary. I'll just leave it on automatic and let it engage each time I shift to park.

As an old friend used to say about the parking pawl, it's not a kickstand.

 

[Jabber]

A couple comments regarding the parking brake....

Automatic transmissions are equipped with a parking pawl which is a metal pin that locks the transmission's output shaft, thereby preventing the transmission gears from turning, thereby preventing the wheels from turning.

The parking pawl is considered a backup to the parking brake. You really shouldn't rely solely on the parking pawl keeping your 5,500 lb truck from moving. When you look at a scene such as cars and trucks parallel parked on steep inclines like you see in San Francisco, it should scare the shit out of you knowing that the vast majority of them probably have no parking brakes engaged. But at least it's not like the ground would ever shake in San Fran and put extra stress on all those parking pawls....LOL.

The practice you should actually observe is to drive to your destination, parking spot, etc., keep the truck in DRIVE, keep your foot on the brake pedal, activate the parking brake, then shift into park. This puts the task of keeping the truck from moving primarily on the parking brake with the parking pawl as backup. This keeps the stress off the transmission components.

I don't know if the GX550's fancy automatic parking brake does anything special, such as making the parking brake the primary and the pawl the secondary. I'll just leave it on automatic and let it engage each time I shift to park.

As an old friend used to say about the parking pawl, it's not a kickstand.

Thanks for that Bill.

I live in the Chicago area. The biggest hill that I can see for hundreds of miles is the rise from street level up the pitch of my driveway. I have however always turned the wheels into the curb when parking on an incline, on top of leaving the car in park and pulling the emergency brake. I'll be good with the automatic parking break system turned off and then doing what is needed (under any circumstance) to secure the car.