Hey guys, My 03 Dmax that has 62k on the OD acted kinda funny today....well kinda is not the word for it. REALLY funny is better.


As I was entering the highway the dang thing would not shift out of 2nd and I noticed that the little light that underlines the gear on the selector was missing. I would show up again in R,3 and 1 but not in N, D or 2.


I pulled over and shut the rig off. Let it sit for a minute while I checked the fluid and inspected for anything gushing fluid. Nothing.


Pulled back onto the highway and all was good to go.


Stopped at the grocery store for about 35 minutes, when I came out and fired up the Dmax and put it in gear it went into Reverse fine, but when I selected drive the driveline slammed HARD into gear.


Again I inspected and nothing. I drove it 3 blocks home to my house with no trouble until I parked it. with the wife shifting I crawled underneath and it lookes like something is loading and unloading really hard inside the tranny.


I mean this is WAY more than just your normal driveline clunk from all the lash of the gears being taken up, it litterally shakes the rig pretty good.


Any experience would be nice. I am taking it into the dealer tomarrow but they are 30 miles away. Safe to drive?


Oh and the 100k warrenty covers the tranny right? I bought my rig in Canada so the normal dealer type warrenty didn't come with it...I don't think.

Not the Allison doesn't fall under the 100K warranty .....


The flashing indicator means there is a code stored .... That is the first step to take, have codes read ...


Stuck in second gear or "limp" mode is what you describe .... You also seem to have a NSBU issue if your getting clunking when changing gears if no longer in limp mode...


Best case scenario is you have a DTC on the NSBU and your good to go ...


Whens the last time you changed the spin on Allison filter ??


Mac

Changed the filter and oil not 2500 miles ago.


what is the NSBU and DTC? I don't speak Chevy Accronym....


I had also just went through a car wash. Seems that some other folks say there is a plug together switch that is water sensitive?


Thanks for all your help.

I'm sorry ...





NSBU is Neutral Safety Backup Switch ...


DTC is Diagnostic trouble code ....


The NSBU is on the drivers side of the Allison Transmission ...It is the switch that gives gear shift indicator gets it's position ... The shift linkage cable is connected and there is a couple electrical connectors ...


Could have just got wet check the connections ...





Mac

I'm sorry ...





NSBU is Neutral Safety Backup Switch ...


DTC is Diagnostic trouble code ....


The NSBU is on the drivers side of the Allison Transmission ...It is the switch that gives gear shift indicator gets it's position ... The shift linkage cable is connected and there is a couple electrical connectors ...


Could have just got wet check the connections ...





Mac





I'll second the nsbu switch. When you replace it, try and make sure its the new and improved one. If i remember correctly there is a newer one than the last replacement that was tan in color, but think the newest one is back to the color black. There is some info around here somewhere, but i can't remeber where is seen it, that will lead you in the right direction.

Well I checked all the connections.....none of them were water soaked but that doesn't really mean anything.


I am taking it in at 1400 hrs today to have it looked at. Is there a TSB out on these old styles?


Mine is black, but it has two plug in's were the newest ones are black with one plug in?


Thanks for the help guys.

IIRC, there is a TSB on that, someone posted about having his done. It's the new black single wire connector switch and requires a mod to the electrical system of the truck for that.


Can't remember exactly where I saw that post, check the TSB section when you search.


edit info:


Check this thread:


http://dieselplace.com/forum/forum_posts.asp?TID=6168&KW=NSBU+switchEdited by: Zeeb

Thanks guys. Turns out that the codes read that it was the NSBU.


They tried to charge me 300 dollars to do the swap. Ummmmm No. I bought it from Dmaxitellitech for like 65 delivered.....I will figure it out for 200 bucks.....

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