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