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USD 272.17
Part #: AT29540479

Allison 29540479 NSBU (Neutral Start Back Up) Switch

Vehicle Fitment:
2001-2004 GM 6.6L Duramax LB7 (Must Verify Your Existing Switch) | See full application list below
Part #: AT29540479
★★★★★ ★★★★★ 4 Reviews
$272.17
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Description

The Allison 29540479 NSBU (Neutral Start Back Up) Switch is an OEM replacement for the faulty NSBU switch in your 2001-2004 GM 6.6L Duramax LB7. Mounted on the transmission housing, the NSBU switch provides selector position information to the TCM. This switch detects the position of the shift lever and communicates to the TCM that the vehicle is in Neutral or Park so that starter can engage. The NSBU switch is known to fail, leading to issues like: no start condition, DTCs for the pressure switch, fail safe mode and incorrect gear showing on display.   

Features: 
  • Dual Connector Switch
  • Genuine OEM Replacement  
  • Installed With Common Hand Tools 
Note: Please visually verify the switch on your transmission has the dual connectors before ordering.  

Vehicle Fitment

YEAR MAKE FOR ENGINE SERIES
2001 Chevy 6.6L LB7 Duramax
2002 Chevy 6.6L LB7 Duramax
2003 Chevy 6.6L LB7 Duramax
2004 Chevy 6.6L LB7 Duramax
2001 GMC 6.6L LB7 Duramax
2002 GMC 6.6L LB7 Duramax
2003 GMC 6.6L LB7 Duramax
2004 GMC 6.6L LB7 Duramax

Specifications

  • MPN 29540479
  • SKU AT29540479
  • ID 5214
  • Manufacturer Name Allison Transmission
  • Shipping Weight 2.00 lb.
  • Shipping Length 4 in.
  • Shipping Width 11 in.
  • Shipping Height 4 in.
  • Fuel Type Diesel
  • Prop 65 Prop 65 WarningWARNING: Cancer & Reproductive Harm - P65Warnings.ca.gov
  • Internal L1.00R1.00

Reviews

★★★★★ ★★★★★
5.0/5 Stars out of 4 Reviews
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5
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7 years old, still works great
5
Swapped this part in 2015, fixed my problem of “range shift inhibited” and been working great since. Couldn’t find the order number but invoice was 951250A
XDP get me what I need AGAIN.
5
Truck would clunk into park with no line under P. Truck would sometimes not start in Park. Replaced NSBU from XDP and all is well. Thanks for providing the diesel community with quality parts.
Exactly Allison part...
5
Truck would bang into reverse and shift light would only show 3rd gear ..before wasting money at a trans shop guys..read the forums and replace this.the hardest part was the plug ..carefully use a small pry tool around the edge as you pull it apart . Trans now shifts perfectly...thanks guys for your help
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Questions and Answers

Would this cause a no start condition?
View Staff Answer 
Answer

Yes, a no start condition is a symptom of a bad NSBU switch. (Check you truck for codes and see where this leads you...could be a bad NSBU)


Fuel economy can vary based on driving conditions, vehicle loads, and driving habits. Most users that don’t’ tow, or tow light loads infrequently, report that they get the best fuel mileage on the higher HP settings. The best way to determine the optimum fuel economy for your vehicle and driving conditions is to try each setting.

Would this caused range shift inhibited?
View Staff Answer 
Answer

A service engine light message that reads "shift range inhibited" is a sign of a bad NSBU switch.

Signs and symptoms of a bad NSBU switch also include (but are not limited to):

No Start

Codes: P0700, P0708, P0847, P0872, P0875, P1711 & P1713

PRNDL (Park, Reverse, Neutral, Drive, Low) not displaying on dash

Engagement issues with the transmission


You may have to go over all of your connections and be sure the NSBU remains in the neutral position. The metal clip (neutral assurance bracket) on the switch helps to ensure the switch is properly aligned to the shaft.

Is this a genuine Allison part?
View Staff Answer 
Answer
Yes, this is a 100% genuine Allison item.
Is this for a 5 speed automatic trans?
View Staff Answer 
Answer

Yes, the Allison NSBU (Neutral Start Back Up) Switch 29540479 is the direct OEM replacement of the NSBU switch found on all Automatic 01-04 GM 6.6L Duramax applications. (You can verify the part number on your truck along with the Allison part number [29540479] of this item.)


The Allison NSBU (Neutral Start Back Up) Switch 29540479 is the direct OEM replacement of the NSBU switch found on all Automatic 01-04 GM 6.6L Duramax applications. (You can verify the part number on your truck along with the Allison part number [29540479] of this item.)


The Allison NSBU (Neutral Start Back Up) Switch 29540479 is Brand New and comes with a 1 year warranty.

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