Changed the ECU. No change.

 

Let's go back to the wiring connections and go over it with a fine tooth comb

 

So when I installed the ECU, the car went into limp mode and was stuck in 3rd or 4th gear only. This happened because the connectors were not all the way seated in the ECU.

Funny thing is, when it was in this limp mode and stuck in 1 gear, the trans was not slipping at all.

Once I rechecked the wiring, I found the connecters were not seated all the way.

I pushed them in tighter and the same issue came back, slipping in 2nd to 3rd.

I agree, it may be a wiring issue.

 

You moved a big chess piece off the board having a spare Engine Ecm for a tester unit.

​​​​I have testers for hard jobs like this to rule stuff out fast! 🤓

Car only has 120k miles so it would seem very rare that the transmission is smoked.

Unless they broke it when it got towed.

What's left?
Bad & damaged wiring
Possible broken transmission
Electrical noise from somewhere or something

Other ideas?

 

2nd/3rd gear shift flare is a common failure mode for that transmission.

 

its just strange the tranny magically broke when he had other unrelated work done. unless they screwde something up. like towed it wrong...

 

I mean come on... Haha

Ok, alternator fails and car dies.

Transmission dies ONE MILE LATER on the way home from the repair shop after work is done.
​​​​​
The odds of the alternator and transmission taking a crap within one mile of each other is astronomical with a RX with 120k miles.

I wouldn't want to put a number on it but how does One in a Million sound??? Haha

What are we missing?
Is the new alternator noisy junk?
Wiring was damaged?
Transmission gave up the ghost?

What is going on? Lol

PS, if this was a machine I was working on for a customer Id be breaking out the scope. I think OP needs to take the car back to where the work was done and have them check it out.

 

I am giving it to a Toyota mechanic friend of mine to see what he finds.
I agree. I just can't buy that the trans went at the same time as the alternator.

 

dealing with something terribly similar to this with my 09 AWD. Wasn't towed. The thing sat for a few days, then got in it to go to the station, shifted funny 3x in a row. Took ot to the shop. Initially thought it was a knock sensor. They tore it down- knock sensors were both fine. Replaced the turbine sensor. Now shifts late and shifts HARD between 2-3-4. Fluid is pink and at correct levels- made sure myself. No funny smells or debris as far as I could tell. It's sitting in the shop right now, as it's undriveable in present hard shifts through 2-4.

he checked the charging system. Said there wasn't any issue- but it had been hesitating to start the first try. I'm at wits end- bought it with 128k- it's sitting at 137 and some change. Any advice?

 

Welcome to Club Lexus and your 1st post!

Another mysterious transmission failure.
Was there any clues or symptoms in the days and weeks leading up to it or did it just happen one day?

 

Did you see them load your car up and tow it on a flat bed? and that they didn't just drag the vehicle in neutral? Did you see it being unloaded? I dont know how long it would take to push the vehicle to screw up the transmission.

 

Just happened one day. Had taken it on a 80 mile round trip the week before, zero issues a s no issues shifting, no problems other than it hesitated to start first try the morning it shifted 3x in less than a block. I'm stumped. It doesn't seem to be a mechanical issue with the trans itself, as it didn't make any noise or shift oddly at all prior. The turbine sensor replacement just moved the weird shifting to 2-4 gears instead of shifting one two three super fast.

 

I hope my transmission never does this crazy stuff because I have nobody I can trust who can diagnose the transmission.

If I take it to a tranny shop, I already know they'll sell me a rebuild without checking anything. Lol

There are tests that can be done on the transmission like checking fluid pressure and stuff but I don't know how to do it.

 

turned out to be either the clock spring or the transmission just wanted serviced- checked out to be fine in fluid color l and had zero debris to be found. We pulled the new turbine sensor off, poked the old one back in, and it shifts like it's never needed the shop at all. Expensive, but meanwhile it's fine. Will be doing another 120 mile round trip thos weekend, we'll see how she does.

 

Was the new turbine sensor a defective aftermarket or OEM?

Maybe the new fluid cleaned up whatever was clogged or jammed up inside the transmission, what's the theory on this friends?