.....Here is my problem!!! I have a stock '02 Chevy K2500HD with the Duramax/Ally combo and yesterday while returning home I pull up to a stop sign and I look down and find that my tranny's shift indicator is in 3. I put the shifter to P but indicator still reads 3 (flashes) and the doors will not atomatically unlock, like they normally do. I unlock the doors and then put shifter to the drive position via feeling the detents on the way down and it indicates 3 once again. I proceed down the road and tranny won't shift out of 3rd range. I then pull into a parking lot, shut down the truck and diconnect the battery, re-connect battery start truck, and all seems fine for about a minute and as I'm accellerating the indicator returns to the # 3 position and tranny will not shift from 3rd. I pull into another parking lot place shifter to park wait for a minute and then select drive via the detents, as now I have no inndications of shifter position at all and proceed home without further adue except the tranny feels like it is in tow/haul mode now instead of normal as shifting seems delayed. Could this be a computer problem?? Any suggestions would be greatly appreaciated!! Also one more symptom is it will not go into 4LO on the 4 wheel drive, the button just flashes, 4HI and 2HI select OK. BTW there are no other abnormal indications ie: SES or other indicator lights??!! Thanx..................................SWH... Edited by: shuffman

Scan it for codes. You probably have a bad Nuetral switch.


mike

Scan it for codes. You probably have a bad Nuetral switch.


mike











Mike:


I think you're right on the money when you say it's a nuetral switch. Here's what I did. This morning after posting my problem I went out and unhooked the neg leads from both batteries. After 40 mins I hooked them back up again. I backed out of the drive way and checked all positions of the shift indicator and found out now only the nuetral position won't illuminate as all other positions do. To confirm it may be a nuetral switch problem I tried selecting 4LO with the shifter in the nuetral detent, but to no avail. It would not engage into 4LO. Tomorrow I'll book it into the dealer with this diagnosis and see if this problem comes up on their scan. BTW, Mike, do you know where this switch is located?? Thanks for your top notch suggestion..............................SWH...

unhooking the batteries will do nothing but loose your clock settings when it comes to clearing codes. OBD-II systems will need a scan tool to clear codes

unhooking the batteries will do nothing but loose your clock settings when it comes to clearing codes. OBD-II systems will need a scan tool to clear codes





That's because he didn't do it right.


You need to disconnect batteries for 5 mins. Once reconnected you have to in order;


1)Flash headlights


2)Beep the horn repeatedly


3)Spin around three times while crossing fingers


4)Bang on dash just incase something came lose


5)Prey


6) Try and start truck!


Hey that was what I was told by a Performance Tuner.


Mac

Oh yeah, NSBU switch. Can be a pain in the ass eh?

unhooking the batteries will do nothing but loose your clock settings when it comes to clearing codes. OBD-II systems will need a scan tool to clear codes





That's because he didn't do it right.


You need to disconnect batteries for 5 mins. Once reconnected you have to in order;


1)Flash headlights


2)Beep the horn repeatedly


3)Spin around three times while crossing fingers


4)Bang on dash just incase something came lose


5)Prey


6) Try and start truck!


Hey that was what I was told by a Performance Tuner.


Mac





So, you read the Quad instructions too huh? http://www.dieselplace.com/forum/smileys/HiHi.gif

unhooking the batteries will do nothing but loose your clock settings when it comes to clearing codes. OBD-II systems will need a scan tool to clear codes





That's because he didn't do it right.


You need to disconnect batteries for 5 mins. Once reconnected you have to in order;


1)Flash headlights


2)Beep the horn repeatedly


3)Spin around three times while crossing fingers


4)Bang on dash just incase something came lose


5)Prey


6) Try and start truck!


Hey that was what I was told by a Performance Tuner.


Mac





Standing on your head for 5 minutes while unzipping/zipping pants 3 times helps too. http://www.dieselplace.com/forum/smileys/HiHi.gif

That's because he didn't do it right.


You need to disconnect batteries for 5 mins. Once reconnected you have to in order;


1)Flash headlights


2)Beep the horn repeatedly


3)Spin around three times while crossing fingers


4)Bang on dash just incase something came lose


5)Prey


6) Try and start truck!


Hey that was what I was told by a Performance Tuner.


Mac





that must not have worked because you forgot to add chocolate mint ice cream to the fuel... that's the final step they left out..http://www.dieselplace.com/forum/smileys/HiHi.gifEdited by: Diesel Power

Gee thanx guys for all the constructive advice. I hope your truck never goes through this. I guess then it'll be my turn to chuck s#@t at y'all. Thanx a lot.......................SWH...

Shuffman





We's just kidding and not at you. The NSBU is located on the driver side of the transmission.


Has a couple electrical connections,two bolts that align and secure the switch to the Allison.


You'll have to remove the shift cable clip ,the bolt on the shaft that the arm is bolted to. Either mark the old switch placement or perhaps the bolts will be the tell tale.


Put the truck in neutral ,of course chalk wheels for safety and apply the E-brake.


The switch is available at any Detroit diesel Allison for 40 ish bucks and it has happened to my truck ,twice.





Mac

Gee thanx guys for all the constructive advice. I hope your truck never goes through this. I guess then it'll be my turn to chuck s#@t at y'all. Thanx a lot.......................SWH...


Don't you think that was a little out of line? I thought we did help you with the info we posted. We all like to kid a little but it was not directed at you.


mike

Gee thanx guys for all the constructive advice. I hope your truck never goes through this. I guess then it'll be my turn to chuck s#@t at y'all. Thanx a lot.......................SWH...


Wow shuffman, I thought it was pretty obvious the guys weren't poking you in the eye. Sometimes a little fun gets the thread off track a little, but that's what makes this all a lot of fun. Take a deep breath, reach a zen like state, then go out and change the switch.


It's all meant in good fun. . .
Dennis

Mike L:


I appologize as my comments yesterday were in no way directed to you. I was a little grumpy yesterday and worried about the problem with my truck. Again I appreciate your suggetstion that it may be the NSBU. I can't see it being anyhting else. It's in the dealership for a scan as we speak for both the PCM and the TCM. I guess yesterday I wasn't in to much of a joking mood and I appologize to the others that answered this thread as well. Hopefully I'll have my truck back tomorrow and all will be well again............................................. .......SWH...

You can order the new tan NSBU from dmaxalliTech from link below. It don’t get no easier than this:
http://www.gmdieseltech.com/store2/cart.php?target=product&action=view&product_id=161 97&category_id=278

Also, see installation info, (from this site), from links below. Anyone should be able to do it themselves.

http://dieselplace.com/forum/forum_posts.asp?TID=10021&PN=1
http://dieselplace.com/forum/forum_posts.asp?TID=9517&PN=1

And buy a spare. You may need it someday. I believe the Dealers get over $100.

Modified:


Thanx very much for the info on the NSBU it's much appreciated. FYI the links you provided throughout your post do not work. I'll keep this package on hand and compare the price of the switch with one at our local Allison service centre. Tomorrow the Chevy dealer will fix my truck as it is still under warranty. Again thanx a lot for the great info.............................SWH...Edited by: shuffman

shuffman


I realize how our trucks can make us grumpy and so do most of the guys here. Thats why we try and have a little fun from time to time. Your truck will be fine (please tell us what fixed it so that we can help someone else). Make sure you stick around as a member. http://www.dieselplace.com/forum/smileys/Hug.gif


mike

Thanx Mike I will hang in here at DP & I will let y'all know the fix asap after I get the truck back tomorrow. I like this forum as you don't have to put up with any Ford or Dodge BS. ..........................SWH...

Mike L:


Well here's the verdict,,,,,Mike you we're right on the money. It was the NSBU in which they changed out in about 45 mins and of course it was covered by the warranty. The code was K5228 part # 29540479. The truck sure works better and all the thanks got to you and Modified who sent me info on how to change out the switch. I'll keep that info for future reference.........................SWH...http://www.dieselplace.com/forum/smileys/Big Smile.gifEdited by: shuffman

Again-my hat goes off to you guys.YOU ARE ALL AWESOME.I have the same tranny problem as Steve just went through.I went to a dealer??? and spoke with the service manager and before i finished giving him all the info he informed me it was a Neutral Safety Switch and priced at $290.00 PLUS LABOR.I called the Allisson dealer across the street from me and they quoted me the RETAIL price of $91.61.That price will be less when I get my neighbor who owns a garage and has an account there to order it for me.

SERVICE from GM DEALERS!!!!! The ones around here are ALL THIEVES.

Don't know if how many miles are on your truck but it may pay to check out the discussion on the NSBU switch at http://dieselplace.com/forum/showthread.php?t=21627

Well Thank you guys for this site !!!!!! I used my truck to help preform a rescue operation with the Fire & EMS service I am on, and ever since I was in 4lo and backing up the snow covered hill into the trees to transport the patient, I have no indication for the tranny and the doors dont auto unlock when I put it in park. wrote Eric and will probly be getting his NSBU this weekend. THANKS GUYS !!!! Your the greatest