Hi everyone! I have a 2003 lexus gx470. My son took it to the Sequoia's and promptly broke down. There are no DTC's, vehicle will not move at all. If I put transfer case in low and gear selector to drive and floor it it will creep forward a tiny bit. Transfer case will not engage in low or high with engine running and gear shifter in neutral, I have to shut engine off then engage transfer case. My son said truck was running great just all sudden quit moving. Not sure if I'm missing something simple or if it's transmission, torque converter or transfer case without any dtc's. Any help would be greatly appreciated!!

 

Will it engage 4x4 mode?
Could very well be fluid level, or bad valve body solenoid.
Diagnostics is the only way.

When was last time pan filter was replaced?

 

Sounds like something severe. Missing fluid. Bad torque converter. Damaged wiring harness.

Hate to ask this - but did they run over anything?

Chip H.

 

2wks later and no OP.
It was a drive-by.

 

No not a drive by! Thanks for the responses. Fluid level is correct and does not appear dirty or burnt, son says he did not run over anything. The filter and fluid were changed about 10,000 miles ago. Truck has 80,000 miles on it. Was running and shifting perfectly normal. 4x4 will engage and transfer case can only be put into gear when engine is not running, otherwise it grinds even if gear shifter is in neutral. Once again thank you.

 

Some very slight grinding when going into 4Lo (and transmission is in Neutral) is normal. A slight buzz/vibration and then it will slot in.

Chip H.

 

Who dropped the trans pan, was that a shop or DIY?

Do the driveshafts feel funny when you try and spin them with wheels off ground?

It does sound like a mechanical issue, but the actual culprit may be lots of things.

Put the trans in N, then try to put transfer into H. Then move trans to a lower gear, does that work?

A silly check, but did the flywheel to converter bolts go missing?

 

Hi thanks for the response. I did the trans service myself. I've moved the gear shifter in every gear and tried to engage transfer case, all has the same result, steady grinding. It's kind of the normal grinding sound before transfer case engages however it will not engage unless engine is off. Ill check the flywheel to converter bolts and driveshafts tomorrow. Really appreciate the input of where to look. It's really frustrating without any codes to know where to look for the problem.

 

The 4x4 HNL stick should be in H position. It sounds like maybe the stick is trying to shift but it cant. That stick is mechanical linkage. It's not 100% clear to me if when the H-L stick is somewhere between H and L if the power would still transfer (I dont think it can in or near N), meaning if it would need a hard set H-L to get power to wheels. I think however if it's not in H or L then it's technically in some "N" position. Does the grinding sound change at all if you change position of 4x4 H-L stick?

There's also a mechanical linkage driver-side just above the pan. Is that good?

If it's just trans issue, I would not expect clutches to be an issue, but I guess that depends on how rough it's been used over the years. I think if friction discs were toasted you just get slipping w/o noise. Though if something else inside broke in trans or xfer case, etc.

Is xfer case oil level good?

If after all your checking and things look eyeball ok, then I would suspect xfer case issue. You could also take a sample of trans and xfer case oil and send those out for UOA test, that might be indicators if something went bad in either.


I asked about DIY pan work, did you use a torque wrench when installing the filter? I think if it fell off there would still be enough oil in there for the pump to get oil though.

 

There is an interlock on the transfer case so you can't shift it unless you're in park or neutral.
The contacts and actuator for it are in a separate compartment. The seal into the main compartment can fail, filling the electrical side and the contacts will no longer work.

Also look at the wiring/connector. I know you said he didn't run over anything, but just in case...

Chip H.