Temp sensor broke...

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Dutch Rutter

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I was in the process of relocating my trans temp sensor from the test port to the pan. Upon removing the sensor It was fully unthreaded and still would not just pull out. I kept threading it out thinking it was hung up a little. When it finally came out I noticed it wasent all there..

Upon further inspection, I found that the freaking cap of the thing broke off and is now stuck in the end of the test port hole. (See pictures)

Any ideas on a way to get this out? It seems pretty stuck so a big part of me just wants to put a short plug over it and hope it doesent end up getting into the fluid passages somehow sometime. I've tried threading a bolt into the stuck part to where it was snugged some and pulled. Thing didn't budge, but the bolt came out.

Why does strange **** like this seem to plague this truck. :banghead: bad juju or something.

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AuroraGirl

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small small drill bit.... left hand thread?
 

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If it’s a turbo 400 trans, it will be ok left in place and capped. The port for the line pressure tap goes into the case a short distance, then makes a 90* turn straight down to the manual valve in the case. The broken off piece won’t restrict fluid to anything.

what probably happened is the sender bottomed out in the poassage, and either bent or mushroomed the end. You tried to unscrew the sensor, but the end wouldn’t turn.

I have no clue if this would do anything other than make a huge mess, but you might be able to blow out the broken part by starting the engine. Unhook the vacuum modulator, start the truck, immediately put the trans in reverse. In reverse, with the modulator unhooked, that’s as high as the line pressure will ever go. If 250plus PSI doesn’t push it out, nothing other than a drill bit would
 

Dutch Rutter

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Thanks all! I should have mentioned this is in a 700r4. I thought about the reverse drill bit or even trying to use a core plug pull tool but figured the brass cap wouldn't hold up enough to actually pull it out.

It is pretty stuck in there and I bet @Matt69olds is right, the end probably mushroomed upon install and got all jammed up in that test port when I tried removing it.

If the only harm in leaving it in there is the test port will be pretty much useless. Then I can live with that. Just didn't want to chance it coming loose inside the trans, clog something up and cause my already troubled 700r4 to become a core deposit for a newly rebuilt unit.

Edit: side note, I successfully replaced the shift shaft seal on the same trans which cured my transmission drip so there's some good news for the day.
 

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Thanks all! I should have mentioned this is in a 700r4. I thought about the reverse drill bit or even trying to use a core plug pull tool but figured the brass cap wouldn't hold up enough to actually pull it out.

It is pretty stuck in there and I bet @Matt69olds is right, the end probably mushroomed upon install and got all jammed up in that test port when I tried removing it.

If the only harm in leaving it in there is the test port will be pretty much useless. Then I can live with that. Just didn't want to chance it coming loose inside the trans, clog something up and cause my already troubled 700r4 to become a core deposit for a newly rebuilt unit.

Edit: side note, I successfully replaced the shift shaft seal on the same trans which cured my transmission drip so there's some good news for the day.
drill center. small.

then step into a slightly larger left hand bit, catch it, then dismount from drill and yank and play it out. it should fold in if you driled it weaker. maybe?
 

Matt69olds

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If the temp sender has been in that port for awhile with no problems, I don’t see leaving in there causing issues now.

Temporarily rig the TV cable to its max travel, start the engine, and put it in reverse. The 700 trans runs more line pressure in reverse than a 400 trans, about 280-300 psi. If that much pressure doesn’t blow it out, I’d say it’s probably not coming out easily.
 

Dutch Rutter

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That was the trick Matt. Did just like you said and at first no fluid at all came out. Then all of a sudden it must have cleared because I got alot of fluid. Shut er down and things look clear. Can't find the reminents amongst the gravel but im confident its all blown out. Added some fluid and all it working well.

Thanks alot!
 

Dutch Rutter

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@Dutch Rutter Joshua, did you put a different sender back in?

I ended up plugging the test port. I will be running a different sender but it'll go in the pan instead of the test port. I figure its a better spot for it. Definitely less chance of getting screwed up like this one did. And hopefully I'll get a more accurate reading of thr fluid teml that the trans is actually pulling in.
 

Matt69olds

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Good deal. It will be interesting to see if the is much of a difference between the pressure port and the pan
 

Dutch Rutter

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what exactly is pressure port for?

From what i understand (which isnt much about automatic transmissions) and @Matt69olds knows alot more about them then I do, it's mainly used for diagnostics, I also think there is a way to adjust a TV cable using that port to verify its setting via trans line pressure.
 

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Don't forget to reset the TV cable
 

Bextreme04

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what exactly is pressure port for?

It's for diagnostics. It tells you what the transmission pressure is during operation, which can help you identify what certain issues might be.

I doubt you would get a very good temperature reading from that location, since the fluid is not circulating at that point. Its just a deadhead and isn't near the main fluid locations. The pan will definitely give you a more accurate reading.

Edited to say: fluid IS NOT circulating at that point.
 
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Matt69olds

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It's for diagnostics. It tells you what the transmission pressure is during operation, which can help you identify what certain issues might be.

I doubt you would get a very good temperature reading from that location, since the fluid is circulating at that point. Its just a deadhead and isn't near the main fluid locations. The pan will definitely give you a more accurate reading.


Exactly. With the sender in the pressure port, your basically reading the temp of the case. The temp is probably slow to rise, and just as slow to cool down.
 

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