Transfer case malfunction 2003 GX470? (1 Viewer)

[kamran2020]

It started about a week ago, when I start driving my 2003 GX470 it would make a loud rattling noise only in the first gear. If I press the accelerator hard it made a metal hitting the metal noise but if I gradually increase the speed it would do fine in first or any other gear. I didn't think much of it and drove to Pensacola (from Atlanta) for the weekend, I did about 70 without no issues. During the trip I had no issues at all only when I stopped at the red light or at stop sign it would make the noise if I accelerate harder.
I brought the vehicle back to Atlanta and took it to my local mechanic (not Lexus/ Toyota specialist). He test drove it and end up putting the vehicle on the lift. He determined the noise was coming from the Transfer case so he took the shaft that goes from the transfer case to the rear axle. It was attached with 4 nut bolts on each side. He suggested I look for the replacement transfer case and he will replace the TC. Currently that shaft is sitting is in the back of my truck. I drove the vehicle from mechanic shop to the house yesterday and it was making some weird noises. This morning when I drove to the airport my vehicle was making some weird noises again and at one of the traffic light it almost felt like the back end of the vehicle wanted to come out of the vehicle.

I am wondering about the following and would love to hear your expert advice,
If I am not planning to use the 4WD, do I need a new transfer case?
Is it safe driving the vehicle when that shaft is sitting inside my vehicle?
Why the ride got so rough after removing that shaft?
Where can I find a decent price transfer case? Is it better to repair the existing TC or get a used replacement?

Any help in this matter would be highly appreciated.

 

[Jstawgn]

The transfer case issue is becoming common due to oil leak. The chain stretched when run without lubricant. The leak are really slow and not noticeable to a lot of people.

There are some people that successfully replace the chain and bearings only. Used case is getting expensive due to this problem. I heard you can get brand new from lexus for less than $2k.

Its safe to drive with just the front drive shaft. But you have to make sure there is oil still in the transfer case. I assume the center diff lock still work since you are still able to drive it. The actuator is expensive too. The chain stretching would still make a lot of noise to drive the front drive shaft

Rear axle is common to fail on this vehicle. Also the driveshaft might be needing new ujoint.

Try car-part.com and Hollanderparts.com to find used parts

 

[kamran2020]

The transfer case issue is becoming common due to oil leak. The chain stretched when run without lubricant. The leak are really slow and not noticeable to a lot of people.

There are some people that successfully replace the chain and bearings only. Used case is getting expensive due to this problem. I heard you can get brand new from lexus for less than $2k.

Its safe to drive with just the front drive shaft. But you have to make sure there is oil still in the transfer case. I assume the center diff lock still work since you are still able to drive it. The actuator is expensive too. The chain stretching would still make a lot of noise to drive the front drive shaft

Rear axle is common to fail on this vehicle. Also the driveshaft might be needing new ujoint.

Try car-part.com and Hollanderparts.com to find used parts

Awesome, thank you for the detailed answer. There is a hope after all. I will share this information with my mechanic and let him figure out the best option.

 

[kamran2020]

Here is an update, after removing the shaft vehicle had some issues with the airbag shocks which was making all the noises. I went ahead and replaced the rear airbag shocks and it stopped all the weird noises. At that time I also went ahead and replaced the gear oil in Transfer case and install the shaft again just to see if it made any difference, it didn't.

For now I am just going to drive the vehicle around without that shaft being I mostly use the vehicle in GA and FL where I dont use 4x4.

 

[SBANGLICO]

You are driving with the rear driveshaft disconnected? Although the truck is AWD, the majority of the power output is through the rear, to the rear axle, by only tooling around with the front driveshaft you are overstressing the front axle; it's not designed to be run as full time FWD. In an emergency, sure, but DD, no. It'll grenade pretty soon especially with the weight of these trucks. You would think a mechanic would let you know that.

Figure out the issue with the TC and get it fixed either DIY or not. I use ECGS for all my gears/axles.

 

[SBANGLICO]

Also are you sure it's the TC? If the sound disappeared when the rear DS was removed it could be the ujoints and or the slip yolk. Relatively easy to replace the joints and grease the slip yoke.

 

[kamran2020]

Also are you sure it's the TC? If the sound disappeared when the rear DS was removed it could be the ujoints and or the slip yolk. Relatively easy to replace the joints and grease the slip yoke.

Mechanic thinks its a TC but I am not 100% sure. We did visually checked the U Joints and there was no issue there. Also the shaft is 3 pieces similar to a folding umbrella (one about an 2" pipe and than 1.75" inside and another 1.5" at the end. He did told me its not the one that you can grease.

 

[SBANGLICO]

I'd seriously question your mechanic. Both the front and rear DS have zerks, along with zerks on all of the Ujoints. So 3 grease fittings both front and rear.

 

[kamran2020]

@SBANGLICO
Thank you so much for this break down details, I am planning to take a vehicle to a different mechanic in next few days. Hopefully its not a transfer case and I can avoid the 2K expense.

 

[kamran2020]

I was able to upload a short video regarding the noise.

IMG_3291.MOV

2003 Lexus GX470 weird noise

forum.ih8mud.com

 

[kamran2020]

I went ahead and purchased a new Transfer Case from Lexus dealership for $2780. Paid $ 700 for labor installation. Don't forget the seal that goes in between TC and Transmission.

 

[kamran2020]

Pic of seal and place of seal.

 

[dynacomp2002]

Did this fix the problem? I think mine's doing it too now...