'02 Duramax 2500 HD w/Allison tranny. I noticed that my shift indicator light (you know, the one that tells you what gear you have selected) was out the other day. Then when I arrived at my destination, the doors did not automatically unlock when I put it in park. Since then this condition has come and gone intermittently. When the biggest inconvienience was having to manually unlock the doors, it wasn't a big deal, however the other day on the freeway at 75 mph the tranny decided that it wanted to drop into 3rd, now it's importance as an issue has elevated a bit. Anyone experience anything similar or have any insights?
Thanks
Gary from Tucson

First make up a sig so we know eveything that you have, do you have any chips or programmers, sounds like a NSBU switch to me.

This happened to my co-workers 01 Duramax. The transmission shift module on side of tranny flaked out. I would get it replaced pronto.
I believe the bad modules are brown or biege and the new ones are black.
Anyone want to chime in here?

Yeah and if you're lucky GM will warranty it under the emissions act.

Thanks gents, taking her in for (extended) warranty action on Friday
Gary

I took it in the the dealer and he found two bad switches (no description on the invoice other than that but I do know that one was inside of the case and one outside.) So far it works well since they perfromed the work.

Howdy Boys...

This discusion caught my eye. Can anyone comment on an automatic door unlock upon shifting in to park? I've owned my first (and only) '02 D-max for almost a year. I have never had my doors automatically unlock (or lock for that matter) as a result of shifting my Allison whatsoever. Is this a standard feature, or something a humble LS trim owner wouldn't know about? Is it a function the previous owner disabled? I'd go look at my owners manual to research this, but my remote hand and beer hand are both busy at the moment.

Curious Aggie in Texas:drinking: