4R44E wont go when OD is on

[BentFenders]

Weird. Should be simple. Truck goes when in any gear unless I turn the OD switch on. Then it is like putting the truck in neutral.
I adjusted the bands but that didn't fix it. Thinking it might be a servo. Anybody have any insights into this maybe?

 

[PopRichie77]

The wires from the OD switch go directly to the PCM (Computer), my best guess is that one of the wires is shorted.

 

[JK080]

Weird. Should be simple. Truck goes when in any gear unless I turn the OD switch on. Then it is like putting the truck in neutral.
I adjusted the bands but that didn't fix it. Thinking it might be a servo. Anybody have any insights into this maybe?

A failed input sprag will do this, you shouldn't have reverse either.

Turning the OD off, turns on the coast clutch inside the transmission, the coast clutch supports the input sprag and that can drive the transmission.

Obviously thats not good, it would have to come out to be fixed.

 

[BentFenders]

The wires from the OD switch go directly to the PCM (Computer), my best guess is that one of the wires is shorted.

I suspected that as first but the fact that something does happen (just not what I want to happen) makes me think the connections are ok. My guess anyhow.

 

[BentFenders]

A failed input sprag will do this, you shouldn't have reverse either.

Turning the OD off, turns on the coast clutch inside the transmission, the coast clutch supports the input sprag and that can drive the transmission.

Obviously thats not good, it would have to come out to be fixed.

Tonight I will check to see if reverse works with the OD switch on. Reverse worked when I parked it though. I just am not sure about the OD switch being on or not.

 

[BentFenders]

Reverse still works. When sitting in drive at idle with the OD on, it is like neutral. Then when I turn the OD off, there is a hardy jolt and then it engages. I am trying to figure out if it is the tranny guts or is it the valve body.

 

[PopRichie77]

You possible have bare and shorted wires in the wire loom in side the pan. That is where I would check first.
Common problem.