Transmission wont shift into 4th/overdrive (1 Viewer)

[vanosmaster]

Hi all,
I’m having a serious issue with my 2000 Lexus LX470 not shifting into 4th/overdrive. I was driving a couple days ago and got an ABS and VSC lights while driving I pulled over and and turned off the car and restarted it, the lights went away and I thought it was a fluke. The brake pedal felt fine and the car still stopped fine.

Today the lights came on and didn’t go away, while continuing to drive it shifted from 4th into third at 70ish mph and will not shift back into 4th. I’ve tried the overdrive off button several times and while the light comes on the engine speed doesnt change. The transmissions still shifts through gears 1-3 like it always did, it just wont go into 4th/overdrive. I am roughly 1,200 miles from my destination and will most likely be able to limp the vehicle but I’m not sure what damage I will be causing here. Does anyone have any ideas on what the issue could be? Could the ABS and transmission issues be related or are they exclusive to each other.

Some other information:
The car has 280,000 miles
The transmission fluid is still red and doesnt smell burnt
The car drove 2000 miles in the last four days before this issue popped up
I recently replaced the front pads/rotors and rear pads a couple weeks ago

Thanks in advance!

 

[MongooseGA]

I replied to you on FB as well but had a thought after seeing you post here.

The transmissions lock out OD when the trucks think they're in low range. There are 2 very simple switches at the transfer case that are not impossible to become fouled over time; their job is to tell the brain "we're in 4 low". They can be "cleaned" with electrical current very easily using a 9v battery. There's a possibility one of those sensors (or the harness running to them) is fouled or damaged. You can test and clean the sensors for free and in very little time. The directions are posted in my own transmission trouble thread on this forum.

 

[JohnMed]

Have you checked your wheel speed sensors? This happened to me, except I did not get a CEL or any other light. One of the wheel speed sensors was barely hanging on by 1 strand of wire

 

[vanosmaster]

Have you checked your wheel speed sensors? This happened to me, except I did not get a CEL or any other light. One of the wheel speed sensors was barely hanging on by 1 strand of wire

View attachment 3969739

I saw your write up regarding the similar issue (thanks for posting!!), I unplugged both front ABS sensors and it did not seem to fix the issue (despite all of the ABS, VSC, Brake lights coming on) I was able to limp the car another ~400 miles closer to my destination and will try unplugging the rear sensors tomorrow to see if that makes a difference.
Will update if this fixes it or if i have time to stop at a mechanic during my trip

 

[JohnMed]

You may want to check at the connection point and inspect wires up to connecting point and check/measure resistance. Not sure if you have tech stream, but (with a friend) you could run tech stream while driving and check to see if sensors are all reading properly as well as check the sensors on side of transmission that also measure transmission revolution. Techstream could also read any potential abs codes to narrow down issue.

 

[AARONTLC]

Hi all,
I’m having a serious issue with my 2000 Lexus LX470 not shifting into 4th/overdrive. I was driving a couple days ago and got an ABS and VSC lights while driving I pulled over and and turned off the car and restarted it, the lights went away and I thought it was a fluke. The brake pedal felt fine and the car still stopped fine.

Today the lights came on and didn’t go away, while continuing to drive it shifted from 4th into third at 70ish mph and will not shift back into 4th. I’ve tried the overdrive off button several times and while the light comes on the engine speed doesnt change. The transmissions still shifts through gears 1-3 like it always did, it just wont go into 4th/overdrive. I am roughly 1,200 miles from my destination and will most likely be able to limp the vehicle but I’m not sure what damage I will be causing here. Does anyone have any ideas on what the issue could be? Could the ABS and transmission issues be related or are they exclusive to each other.

Some other information:
The car has 280,000 miles
The transmission fluid is still red and doesnt smell burnt
The car drove 2000 miles in the last four days before this issue popped up
I recently replaced the front pads/rotors and rear pads a couple weeks ago

Thanks in advance!

Verify that no mice have started chewing on the wires coming out of your brake booster and make sure you do not have a leak from your booster down onto the terminals at the bottom of the booster. Will cause corrosion and ABS/VSC lights.