Transmission eating sensors

2001 4.7L. Truck is running fine. Shifting a little late but fine there no noises. It started with code P0715. Input turbine speed sensor. I replaced the sensor. Light stayed on. After about 100 miles pulled the sensor and it has been ground down to the copper. I compared both the sensors and then noticed that the original sensor was also started to wear in the same spot. I've attached pictures of both inside where the sensor sits and of the ground down sensor. I do not know what is on the other side of the sensor but it also seems to be damaged now. I compared the new and old sensor and they are the same length. I know I'll probably have to take it in to a transmission shop. However if anyone can give me some advice as to what is actually going on I appreciate it.

 

Bummer to hear this. What part number is this? How many miles on truck?

 

Is there a shim that's supposed to go between the sensor and transmission or maybe the gasket, if needed, isn't as thick as the original? This site says they're Toyota parts, go thru the settings because it's probably selected for my truck.

 

Looks like the sensor is being milled by whatever rotating component it's supposed to monitor.

If the sensor hasn't changed its position in the transmission, then a spinny object has.


No bueno.

 

Part # 8941150010, bought is from Toyota. Same size as the one I removed. About 280k miles on it now.

 

Best I can tell no, there wasn't one when I removed the old one which has been on the truck since before we got it over 70k miles. It only seals with an oring. After this I noticed the one I removed initially was also starting to wear like this though not nearly as bad. Both are the same size so the new one wasn't sitting in any further.

 

That is the conclusion I had come to as well. The old sensor was starting to get worn down in the same area just not as much. I didn't notice until I saw this and compared them that it was even damaged as well. I tried looking up diagrams and pictures that might tell me what that part is on the inside, but I couldn't figure it out. Transmission seems to be functioning just fine. It's never slipped or made noise. This problem popped up in the last 200 miles.

 

Could it be the input shaft?

 

Without a schematic I'm in the dark...

 

I appreciate you responding. From what I was reading, the turbine input sensor reads the input shaft speed. I haven't gotten much further than that yet. I've looked up pictures but there's not much on my end to compare. Though I'm guessing the smooth metal inside the transmission is supposed to not be so smooth.

 

If the transmission is still working fine I'd be tempted to just shim it out with a couple washers and see what happens. Not the right fix but with almost 300k I'd plan for a rebuild/replacement and just run it until it starts acting up.

 

I'm having a hard time visualizing where the sensor mounts? Is it "reading" off the flexplate?

 

It looks like a part similar to the crankshaft position sensor which I've replaced several times on automatic trans Jeeps. From a Jeep perspective: It's mounted on the bell housing and takes readings from the torque converter. It shouldn't come in contact with the torque converter... rather slightly spaced from it when mounted to the bell housing. I believe there is a small magnet inside the sensor that picks up data. If it's making contact and breaking, your sensor is too long (possibly wrong part) or something's not right with the torque converter. Possibly missing a sensor spacer/washer or need to try a spacer/washer as others have mentioned.

 

I'd have a helper slowly rotate the crank shaft on the engine while I looked in the hole with a flashlight. As @Glock 40 said, something metallic is supposed to come in close proximity to the sensor (it's a simple Hall Effect sensor that works on the same principle as the ABS sensor). Clearly something is out of whack, so it's making contact where it shouldn't. I'm surprised you're not hearing a sound from it.

 

Agree with @tvpierce.

It's a proximity switch that's reading the shaft speed by sensing that notch on the shaft. As others have said, try "shimming" it out slightly, maybe 0.030" (1/32") to move the tip away from the shaft. The trick will be finding something that seals the opening, and is thick enough to "shim" it out without increasing the gap so much that the switch no longer senses the notch at all; i.e. always "zero rpm". Tried a fat new o-ring yet?

 

From what I’ve been able to determine, the reluctor wheel for the turbine speed sensor on the A340 transmission is attached to the O.D. planetary set up front, and looks like this.



The 16 tooth ring around the top of the planetary that appears to be spot welded on in 3 places.

There are a few possibilities for why it’s attacking the sensor.
-Bearing or bushing play allowing the whole thing to move off of center.
-debris floating around getting stirred up by the reluctor wheel
-broken spot weld(s) attaching the reluctor wheel, so it’s no longer centered.

In any case, unfortunately, a transmission swap or disassembly for rebuild is in your near future.

 

Thank you, I just saw all these replies. I think you hit the nail on the head. The bearing was my guess the more I looked into it, but either of the other scenarios could easily cause similar issues. Thank you for the picture It really helps with the visualization of it. I mean I knew it was going to come down to at least the transmission dropping. This part alone from Toyota I believe was about $730 so I believe having the transmission replaces with an 03' and up is probably the best solution. I really appreciate your in depth analysis. Funding will be the difficult part, but at least it's motivation to get my camry smogged and registered now.

 

I will admit this was one of the first "bandaid" solutions that popped to mind lol thank you.

 

Thank you, my cousin was helping me and suggested something similar. After finding the brand new sensor destroyed after just wanting to inspect it, my somewhat angry self just said slap it back together. I should've listened. He works for a car lot so I think my next step is to talk the mechanic he uses. That's why I was so surprised that it was destroyed. No noises and working fine, but most of the sensor is plastic so I guess it wouldn't be too noisy.

 

Yes, looks basically the same as the crankshaft position sensors I've replaced. The sensors were identical after seeing what happened to the new one I noticed the original sensor was wearing similar just to a much smaller extent. Thank you.

 

If you want to shim it try using the cardboard from the back of a notepad using an old sensor as template of sort, since it has an 'O' ring there shouldn't be any leakage. I'm no transmission or auto mechanic by any means but one thing to keep in mind you've lost 2 sensors if I'm correct so you've got debris from them floating around in your transmission.