2011 Dmax/Ally trans temp reading fail

[D60]

Looking at an '11 3500 with Ally and has P0711 and P0712. Temp will go from insisting it's overheating to normal temps, might jump around a lot....109, 140, 183, 135 then just go to dashes (--) ie no reading at all.

I was able to wiggle the obviously leaking connector at rear of trans and force the temp from 109 (probably accurate at the time) to 316 or 320 and then reverse direction and back to 109.

Thus I'm gonna say flakey connection/ATF contamination at plug.

So the question is do I just replace the seal/washer at connector (I think MA sells just the seal), or the entire internal harness? While the pan is down do I also replace the manifold to get a new sensor and head off future problems?

273k mi on vehicle. Hoping @clinebarger has advice

 

[dnewton3]

Disconnect the harness and look for the "green crusties" (corrosion). You may be able to fix it with just diligent cleaning and some application of DeOxit D5 (electrical contact deoxidizer spray; Amazon, etc).

 

[clinebarger]

The fluid is coming from inside the connector not the OD seal that seals the bulkhead to the case, Install a new internal harness.

Carefully inspect the external harness for circuits shorting to each other after cleaning it up, ATF isn't vey kind to the insulation.

 

[D60]

Carefully inspect the external harness for circuits shorting to each other after cleaning it up, ATF isn't vey kind to the insulation.

I did find one wire that is displeased. My Google-fu is coming up short this morning -- any idea what this wire is responsible for?

It has a black stripe but I'm not sure if the primary color was considered yellow or maybe tan? 2011 MY

 

[clinebarger]

Temp sensor signal circuit

 

[mattd]

That’s your issue.

 

[D60]

Thank you all and esp clinebarger. I did replace the internal harness anyway because it was leaking so badly, and the owner wanted a full service so while the pan is off that's THE time to deal with the internal harness.

I used a Rostra because IIRC @clinebarger told me in the past their stuff is good. Pretty sure I put a Rostra in the '08 years ago.

 

[clinebarger]

Rostra uses genuine Aptiv/Delphi connectors & terminals, The wiring is decent.....Fit can be off from OE & you need to make sure none of the unprotected portions of the harness are against anything.