Well the ole NSBU bug finally hit and I'm glad it did.I'm going on an 850 mile trip next Wednesday morning and what a pain if it had gone out on the road.I printed out the instructions supplied by Alaska Duramax and it sure takes any confusion out of the R&R.It took about 30 minutes in my garage(2 Pyramid India pale ales) and the only tough part was getting the new switch to slide over the shaft.Filing the peened portion where the flats start on the shaft per Duramaxallitech solved that.Had a ton of mud, rocks and other crap collected behind the switch but that pretty much fell out when I pulled the old one off.This site rules and has been a fantastic resource of help and info!!!
Thanks to all and HAPPY NEW YEAR!!!!!

Blake :ro)

Pardon my ignorance, but what is the NSBU switch?

Thanks, Brian.

Pardon my ignorance, but what is the NSBU switch?

Thanks, Brian.Neutral Safety Back Up switch
It is on the side of the transmission and will screw with the Allison if bad or misadjusted.

One of the tech's here could explain the technichal details...........all i know is if it doesn't work correctly your tranny won't either.

T:cool: NY

Thanks GMC 2002.


Brian.

Mine went 3 weeks ago at 35000 miles. It was a bad snow storm and the tranny kept limping. Thankfully it was still under warranty.

Is "limping" when it's in gear and acts like it's in neutral? Mine keeps doing this and I get the message "shift range inhibited." Dealer can't duplicate. Could this be the NSBU switch? Thanks!

Someone please tell me why all these NSBU switch problems? My truck is a "working truck" with almost 400k & I have never had a problem with this. Are aftermarket add-ons causing this? If so tell us what it is so I dont add it.

Someone please tell me why all these NSBU switch problems? My truck is a "working truck" with almost 400k & I have never had a problem with this. Are aftermarket add-ons causing this? If so tell us what it is so I dont add it.
400k, wow that sounds like the highest mileage i heard about, so what problems have you had, any mods done, mileage, thanks for the reply

Only mods to my truck was the Amsoil bypass oil kit & a 115 gal. tank with a aux. filter befor the OEM filter. Injector probs started at 215k . 3 failures later at 282k motor blew. IMHO, it was because of diesel dumping into the oil. With each failure the oil pressure dropped a little, even though GM insisted the fuel in oil "wont hurt anything". Installed a new motor at 282k Jan 12, 04. It now has 112k on it & so far no probs.

Someone please tell me why all these NSBU switch problems? My truck is a "working truck" with almost 400k & I have never had a problem with this. Are aftermarket add-ons causing this? If so tell us what it is so I dont add it.

Its a known problem and has to do with moisture getting to the electronics of the switch IIRC.
I'm going to drill the rivets out of mine and see what the guts look like.I'll post some pics if I see anything interesting.

Blake

Only mods to my truck was the Amsoil bypass oil kit & a 115 gal. tank with a aux. filter befor the OEM filter. Injector probs started at 215k . 3 failures later at 282k motor blew. IMHO, it was because of diesel dumping into the oil. With each failure the oil pressure dropped a little, even though GM insisted the fuel in oil "wont hurt anything". Installed a new motor at 282k Jan 12, 04. It now has 112k on it & so far no probs.
that sucks about the motor going, i did hear of a few members filling their crankcases with diesel, beaware done the road