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

[deshet]

I'm currently tracing cables to the transmission relay. I believe it is a small box that is mounted to the rear of the battery box on the passenger side

Looking for 29 BT

I have found
89
290 291 537
57T
599C

I also am trying to figure out how the transmission main harness disconnects. I believe on the civilian versions it just pulls out but I can't get a good enough visual to determine how the connector comes out. I was also getting bitten a lot by mosquitoes last night so I didn't give it as much time as I can today.

I saw a kit last night that converts the 4L80E to a clutchless manual, I don't believe it will get to that point but I guess it's an option.

I appreciate the support.

Thanks

 

[Mogman]

I'm currently tracing cables to the transmission relay. I believe it is a small box that is mounted to the rear of the battery box on the passenger side

Looking for 29 BT

I have found
89
290 291 537
57T
599C

I also am trying to figure out how the transmission main harness disconnects. I believe on the civilian versions it just pulls out but I can't get a good enough visual to determine how the connector comes out. I was also getting bitten a lot by mosquitoes last night so I didn't give it as much time as I can today.

I saw a kit last night that converts the 4L80E to a clutchless manual, I don't believe it will get to that point but I guess it's an option.

I appreciate the support.

Thanks

It is there, but it could be a #29 with a different suffix, there are several #29s in that area and someone could have connected them differently, all the #29 wires should be switched 24V

 

[Mogman]

The B means it is black, it will not be marked BT, only T etc.

 

[deshet]

Another member gave me advice via PM and he mistyped the number.

Definitely learning a lot about this truck pretty quickly.


My civilian 6.5's have been pretty reliable. The most common problem was the injection pump (PMD) computer needing to be moved due to heat.

I should have many of the common problems tracked down once I get these going. It seems like internal damage to the transmission is not very common and I usually have good luck.

Thank again

 

[thompsoncustom]

When I got my humvee I was getting the same code 73 and these guys helped me out a bunch.

My problem ended up being voltage. I was getting something like 3 less volts at the batteries than at the alternator, where the alternator wires transfer power through the body and into the battery box with long bolts I had one that was a little loose, after cleaning everything up and tightening it all down good my issues went away.

Not saying this is your problem but just wanted to let you know that lower voltage can throw this code.

 

[deshet]

I appreciate the last response that gives me something else to check.

Today I removed the main harness plug going to the transmission.
It was clean no fluid in it (picture attached)
I could see a very small amount of fluid basically a drop that looked like it was on the side of the o-ring for the main connector on the transmission.
I believe it was transmission fluid but it has been raining the last few days here so I cannot confirm for 100%.

Also I cleared the transmission codes and drove it again.

It seems to shift at 10 mph and 18 mph I didn't take it much beyond that but it did the same thing four times.

I checked the codes again after and I'm still only getting code 73.

Near the coolant filI did see something that was disconnected can't tell if it's supposed to be like that or not. Picture attached it's the second one

Thanks

 

[Coug]

I appreciate the last response that gives me something else to check.

Today I removed the main harness plug going to the transmission.
It was clean no fluid in it (picture attached)
I could see a very small amount of fluid basically a drop that looked like it was on the side of the o-ring for the main connector on the transmission.
I believe it was transmission fluid but it has been raining the last few days here so I cannot confirm for 100%.

Also I cleared the transmission codes and drove it again.

It seems to shift at 10 mph and 18 mph I didn't take it much beyond that but it did the same thing four times.

I checked the codes again after and I'm still only getting code 73.

Near the coolant filI did see something that was disconnected can't tell if it's supposed to be like that or not. Picture attached it's the second one

Thanks

second picture is the vent for the fuel tank. It's supposed to look like that; it's just a standard type fuel filter to keep dust and dirt from getting into the system.

 

[Mogman]

Look at page 99 of the supplement.
Check continuity from pin D of the trans connector to pin k of the TCM harness connector.
Do the same thing from pin C and g NOTICE the underline on k and g of the schematic, that means they are talking about the lower case pins, there are more than 22 pins so there are upper and lower case pins on that connector, generally I,O,Q and Y are not used on connectors hence the reference to more than 22 pins.
There is a clear picture of the TCM harness connector on page 137

 

[deshet]

Look at page 99 of the supplement.
Check continuity from pin D of the trans connector to pin k of the TCM harness connector.
Do the same thing from pin C and g NOTICE the underline on k and g of the schematic, that means they are talking about the lower case pins, there are more than 22 pins so there are upper and lower case pins on that connector, generally I,O,Q and Y are not used on connectors hence the reference to more than 22 pins.
There is a clear picture of the TCM harness connector on page 137

Thanks for the detailed response. Is there a procedure to verify the internal wiring hardness inside the transmission? Is seems like something internally isn't getting a good signal based on the way the light comes on immediately.


Sorry that it took so long to so long to respond
I have continuity between D&k and C&g.

There were a couple drops of fluid in the transmission connector but not anything serious. Nothing dripped while running the different tests. It was just a couple drops when I disconnected the connector. I believe that the 3xxx miles on this truck are accurate based on the condition of the frame, bolts, body, etc

In the other recommendations

Thanks again.

 

[deshet]

This morning I removed and cleaned all of the connections to the alternator. None of them were dirty considering what most diesels' look like. The main 24v connection had a little grease built up. Everything has been cleaned and reinstalled. No change to the shifting pattern.

It seems to shift between 1 and 2nd and remain in second.

The transmission light is on and remains on as soon as power is applied. If I erase the TCM codes (pulling the TCM plug cannon plug) the transmission light comes on as soon as everything is reconnected.

Thanks

 

[Mogman]

This morning I removed and cleaned all of the connections to the alternator. None of them were dirty considering what most diesels' look like. The main 24v connection had a little grease built up. Everything has been cleaned and reinstalled. No change to the shifting pattern.

It seems to shift between 1 and 2nd and remain in second.

The transmission light is on and remains on as soon as power is applied. If I erase the TCM codes (pulling the TCM plug cannon plug) the transmission light comes on as soon as everything is reconnected.

Thanks

The trans light should be on until you start the truck then go off when the engine is started, what codes are you seeing?

 

[deshet]

I am still getting code 73..

Thanks

 

[Mogman]

I am still getting code 73..

Thanks

Have you gone through the troubleshooting for code 73 in the 4l80e supplemental guide?

 

[deshet]

Thanks for the support.

g to C have continuity
k to D have continuity
k to g 4.8 ohms
C to D shows open.

I need to drop the pan. Although the fluid looks brand new I will probably change it and the filter. Is the filter the same as the civilian vehicle filter

Is the pressure control solenoid specific to the military application or can I get one for a civilian vehicle. Has anyone had better luck with a specific brand?

Code 73 remains

Thanks

 

[Mogman]

Same components as civy transmissions, 4.8 ohms is right on the nose for the 4L80E considering you can have up to .5 ohms loss in your test leads and there is a small amount of loss in the wiring from the solenoid to the TCM plug.
It is possible the PCS circuit is bad in that TCM, if you can lay your hands on another one swap them out to test.

 

[deshet]

Same components as civy transmissions, 4.8 ohms is right on the nose for the 4L80E considering you can have up to .5 ohms loss in your test leads and there is a small amount of loss in the wiring from the solenoid to the TCM plug.
It is possible the PCS circuit is bad in that TCM, if you can lay your hands on another one swap them out to test.
View attachment 931040

I am trying to understand things in more detail.
I didn't have continuity between C and D doesn't that point to an internal problem or the solenoid?
Is the removal of the TCM straight forward. I don't want to damage it by pulling the TCM from my other truck. It is also m1079a2 with the 4l80e.

 

[Mogman]

You said you had 4.8 ohms from k and g was that with the cannon plug removed from the TCM box?
If so you likely have the same thing at C and D,
Swapping is simple just unbolt the TCM case (4 1/4" nuts) from underneath the body and pull the box.

 

[deshet]

The cannon plug (J1) on the TCM was removed.
I don't have the test cable (J-44152) listed in the manual.
I don't have resistance between C and D. The result is an open circuit. I checked this multiple times.


Seem like the problem is pointing to the pressure control solenoid.

I appreciate all of the support. Please let me know if your recommendations remain the same or if I should try something different

Thanks

 

[deshet]

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

 

[Mogman]

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

The C and D you see on the schematic is for the connector at the trans not at the TCM, the ones you want to look at at the cannon plug (J1) for the TCM is lower case k and g
D and C on that connector is used for something else.