Factory trans temp sending unit

[dan brooks]

Anyone know the part number for the stock trans temp sending unit? I'm starting to have some overdrive shifting issues again and think that may be the problem. So far I haven't been able to find a replacement, though... .

 

[dpuckett]

How's your TPS? I had one crap out on me after 5000mi. I decided then to start looking for another truck, as this was the 3rd one I'd put in inside of 25K. I didnt know about taking them apart and cleaning them then. Not to say it ISNT your transmission temp sender, just warning you the TPS can be a PITA.



Daniel

 

[dan brooks]

TPS seems to be fine. Last time it acted like this it was a bad connection at the temp sending unit, but I just cleaned and greased it when I installed the cooler less than two weeks ago. The sender is cheaper than the TPS, so it's a good place to start.

 

[cerberusiam]

If you want to verify it is the trans temp sender just jumper the plug so it is closed and see if that makes a difference.



There was a thread back a while that I think ended up with an aftermarket one that would work. Try searching if you haven't already.

 

[dan brooks]

Did a search - actually a couple different ways - looking for the part number, but all I found were posts about where to put the sender for an aftermarket gauge.



I need to dig out the FSM and see if it gives the specs for the sender. If so I may just get a resistor and wire that in.

 

[dan brooks]

Well, the FSM doesn't give any specs on the sending unit. So, other than replacing it and hoping that corrects the problem I guess there is no way to check it.



Now I just have to find one... .

 

[Hunter4x4]

Dan -



My $0. 02 worth..... If you're talking about the temp sending unit in the transmission cooling line, that fella doesn't kick in until about 270*. According to my FSM, the only thing that sending unit does is at a fluid temp of 270* it prevents the transmission from shifting up into OD, via the PCM. So unless your transmission has been running hot I don't think that's the culprit. In fact, I know a lot of guys that just remove the factory sending unit and use that location for their aftermarket transmission temp gauges.



Also, earlier this year my transmission guy friend told me that in these trannys OD is the first thing to go when the transmission starts getting tired. Hope it's not that for you though but something simple.



Mike

 

[dan brooks]

Trans was just gone through a few months ago, and the problem occasionally happened before then. I've always been able to "fix" the problem by cleaning the connector and packing it with dielectric grease, but that didn't work this time.



The sensor is a dealer-only part, $57, but I'm having my friend see what he can get it for through the shop. I'd like to just eliminate it, but I keep hearing conflicting info whether bypassing it will cause any computer-related issues. So, it looks like I'll be swapping it out... .



One of the builders at the shop said it's not uncommon for the sending unit to fail and cause exactly what I'm experiencing - he's convinced that is the problem.

 

[cerberusiam]

There are no specs on the sending unit because it is an open/closed type unit. If the trans overtemps the sensor breaks the contact and the PCM see's no voltage and drops the trans out of overdrive. The voltage is supplied by the PCM and read by the PCM so no resistor is needed.

 

[dan brooks]

Ah, I was wondering if it was just an open/closed switch or a variable sending unit. Checking it out with an ohm meter showed it was closed, but my electrical skills are lacking to say the least.



I may try to rig up a jumper and see if that will work before I fork over the cash... .