2010 6.5 4l80 gets to 50 no overdrive and no trans light

[Mogman]

If as you stated earlier you are seeing 4.8 ohms at the J1 TCM connector lower case k and g then the PCS coil is probably OK.
If you do see 4.8 ohms at k and g then it is time to pull the TCM, box and all and put it on the bench and open it up and check for moisture.
If everything is dry then check for continuity between the J1 connector on the box to the connector to the TCM itself, lower case k to C15 and lower case g and D16 if all that checks out then I would substitute the TCM and see if the code 73 is still set.

 

[deshet]

I appreciate the support .
Maybe I am not understanding the flow of things correctly.
I believe the open / no continuity / no resistance between C and D point to the transmission, based on the resistance reading being taken at the J1 connector while it was disconnected from the TCM but still plugged into the transmission.
Please don't think I am trying to be argumentative by any means as you definitely know more than I do about these vehicles.
I don't understand the reasoning behind swapping out the TCM unless your experience is pointing towards 2 separate problems and the continuity issue between C and D is not an issue.

I've reviewed as many historical post on this as possible to get a better understanding. It appears that C and D are the electrical connections to the pressure control solenoid.


Is failure of the pressure control solenoid rare, it seems like internal wiring problems are common.

I'm hoping that this clarified things. I will accomplish the next steps this weekend and report back

Thanks

 

[Mogman]

Again the C and D pins associated with the PCS circuit are at the transmission connector not the J1 TCM connector You are looking at the wrong connector for the C and D pins,

look at the schematic I posted above and it is simple to see.

You will not get continuity at the C and D pins at the J1 TCM connector, but the fact you ARE seeing 4.8 Ohms at pins lower case k and g at the J1 TCM connector suggests the PCS coil and associated wiring is probably OK, if the PCS coil is ok then there is the possibility of a bad I/O port (the PCS port) in the TCM.
That is why I suggested a TCM swap

 

[Mogman]

No continuity or resistance between C and D in the J1 TCM connector

I will again try to explain, thes pictures in your post are of the J1 connector at the TCM, the C and D pins on this connector have nothing to do with the PCS circuit, however the lower case k and g are part of the PCS circuit, you reported seeing 4.8 ohms there which would be in line with a good PCS coil.

 

[deshet]

I will swap the TCM between trucks this weekend. I attached the page from the tech manual that I was referring to. It states to drop the transmission pan if resistance is not found between C&D for code 73.

The first few things you guys had me try seemed to be in line with the troubleshooting provided in this attachment.

Please let me know if I'm using the wrong version.

I really appreciate the patience and support

 

[Mogman]

I will swap the TCM between trucks this weekend. I attached the page from the tech manual that I was referring to. It states to drop the transmission pan if resistance is not found between C&D for code 73.

The first few things you guys had me try seemed to be in line with the troubleshooting provided in this attachment.

Please let me know if I'm using the wrong version.

I really appreciate the patience and supportView attachment 931109

Yes, that is C and D on the transmission connector not the J1 TCM, you would need a special cable (as it states) because it is very difficult to access the transmission connector to measure it with meter leads.

Notice it does not reference J1 in the procedure, only the special test cable, that cable attaches to the transmission not J1.

Again easy to see on this schematic, you are basically doing the exact same measurement at the J1 TCM connector only you are including possible faults in the wiring, so seeing 4.8 ohms at the lower case k and g on the J1 TCM connector tests the PCS, the internal harness and the wire harness from the transmission to the J1 TCM connector, again you are looking at the wrong connector in reference to C and D

 

[deshet]

I really appreciate you clearing that up for me.

I was using a different post. That described a similar problem and I misread what you initially wrote. That is my mistake.

4l80e pressure control solenoid

hello, I have a new to me humvee with the N/A 6.5 and 4l80e transmission and have been changing fluids and doing some little maintance and driving around town. everything seems good except the transmission seems a little confused if it should shift up or down in overdrive. found on here how to...

www.steelsoldiers.com

What is a reasonable price to pay for a replacement TCM, is there something internally that is typically goes bad?

The covers for the TCMs look slightly different between the two trucks. The connection is the same. I will have them swapped soon and report back

I definitely appreciate your patience

 

[Mogman]

I really appreciate you clearing that up for me.

I was using a different post. That described a similar problem and I misread what you initially wrote. That is my mistake.

4l80e pressure control solenoid

hello, I have a new to me humvee with the N/A 6.5 and 4l80e transmission and have been changing fluids and doing some little maintance and driving around town. everything seems good except the transmission seems a little confused if it should shift up or down in overdrive. found on here how to...

www.steelsoldiers.com

What is a reasonable price to pay for a replacement TCM, is there something internally that is typically goes bad?

The covers for the TCMs look slightly different between the two trucks. The connection is the same. I will have them swapped soon and report back

I definitely appreciate your patience

The first thing you need to do is pull the TCM box and open it up, water intrusion is very common, sometimes you can dry them out, sometimes it is too late.
Yes there are a couple different styles of TCM boxes and TCMs themselves, all TCMs will interchange, some have different shift points depending if they are turbo or NA trucks.
Since you have another truck I would swap them first to see what happens, I cannot say that TCM is bad but it is possible given the troubleshooting you have done.

 

[deshet]

I managed to switch to the TCM. Everything seems to be operating properly at this point. No TCM light or codes.

I still need to open up the original TCM to see if anything is obviously wrong. I saw on a YouTube video that members here have suggested Rock Auto for a replacement place. Does anyone have a part number?

I appreciate the support and patience in resolving this problem.

Thanks

 

[deshet]

If as you stated earlier you are seeing 4.8 ohms at the J1 TCM connector lower case k and g then the PCS coil is probably OK.
If you do see 4.8 ohms at k and g then it is time to pull the TCM, box and all and put it on the bench and open it up and check for moisture.
If everything is dry then check for continuity between the J1 connector on the box to the connector to the TCM itself, lower case k to C15 and lower case g and D16 if all that checks out then I would substitute the TCM and see if the code 73 is still set.

I have taken apart the original TCM. The seal on the case was pretty strong.

It is completely dry.

I test continuity between the two purple plugs and the J1 and the other 6 pin external TCM connector.

I get continuity across all connections.

k to c15 .3 ohms of resistance
g to D16 .3 ohms of resistance

Should I look at anything else while this is apart.

Thanks for all of the help. I took the hmmwv on the interstate today and it preformed well with the swapped TCM. So far I have only had to tighten a lower radiator hose.

 

[Mogman]

I have taken apart the original TCM. The seal on the case was pretty strong.

It is completely dry.

I test continuity between the two purple plugs and the J1 and the other 6 pin external TCM connector.

I get continuity across all connections.

k to c15 .3 ohms of resistance
g to D16 .3 ohms of resistance

Should I look at anything else while this is apart.

Thanks for all of the help. I took the hmmwv on the interstate today and it preformed well with the swapped TCM. So far I have only had to tighten a lower radiator hose.

No, IMHO you have proven that TCM is bad
That makes the third one in a row that turned out to have had a bad I/O port on the TCM
ronbo-3 steelsoldiers and now you.
I would have thought the PCS would be a robust and reliable unit but that does not seem to be so.

 

[deshet]

Is there a replacement TCM that makes sense. I was watching a YouTube video and a person stated that the guys at steel soldiers helped him find a TCM replacement on from rock auto. Unfortunately, he didn't list a part number or price but stated that was cheaper than he was able to find one. My TCM seems to look different than the one in the video.

I have seen automotive computer rebuilders online. I may go that route before spending $500 on a TCM.

I appreciate the support.

Mogman,

In a previous post you said that all of the TCMs are interchangeable but that some have different shift points based on turbo vs non turbo etc. Is that true for all Hmmwv's or just the ones with 4l80e? Is the TCM compatible for the Hmmwv that have a 3 speed transmission?

Thanks

 

[Mogman]

Is there a replacement TCM that makes sense. I was watching a YouTube video and a person stated that the guys a steel soldiers helped him find a TCM replacement on from I believe rock auto.

I have seen automotive computer rebuilders online. I may go that route before spending $500 on a TCM.

I appreciate the support.

Mogman,

In a previous post you said that all of the TCMs are interchangeable but that some have different shift points based on turbo vs non turbo etc. Is that true for all Hmmwv's or just the ones with 4l80e? Is the TCM compatible for the Hmmwv that have a 3 speed transmission?

Thanks

The 3 speed trucks do not have a TCM, they are mechanical

 

[deshet]

I noticed that this ground wire is loose, could that cause the TCM code or would that have caused several others codes?

I may tighten it and reinstall to see if the problem remains, unless the loose wire would have caused a bunch of codes or no codes at all.

Thanks

 

[Mogman]

I noticed that this ground wire is loose, could that cause the TCM code or would that have caused several others codes?

I may tighten it and reinstall to see if the problem remains, unless the loose wire would have caused a bunch of codes or no codes at all.

Thanks

I could not say, but it will not cost anything to try! I certainly would.