Converter not locking up?
 

1996 dodge 3500 duelly. Driving the truck easy with the overdrive turned off, it seems like the converter keeps locking and unlocking when the truck is in third gear. When I drive fast enough to use the overdrive( forth gear) and have it turned on, the converter seems to be working ok and stays locked in. Changed the fluid and adjusted the bands but that didn't change what it's doing. Is the tranny going out??? It pulls fine and doesn't slip- it's just that I don't think the converter is staying locked in when it's in third gear. I might have a tad too much fluid in the trans at the moment but the trans has acted the same before and after I fooled with it. Any help is apreciated.

Sounds like a TPS issue. Try cleaning and adjusting it.

Dodge diesel maintenance tips

About half way down the page.

I didn't think that a 1996 had a TPS? It's a 12 valve with a mechanical pump...right???

Mounted right on the side of the throttle linkage!

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If that doesn't work, try unhooking you alternator completely, take all the wires off of it and secure and cover them so they cant short out, I had a 97 at work that was doing this and it was a bad alternator, causing feedback into the reference circuit on the pcm. Drive it with the alternator undone and if the converter acts normally, you most likely need to replace the alternator.

Thanks , I'll give it a try and let you know. Might be a little while because the truck I am working on in out and about most of the time.