2001-2007 Duramax Transfer Case Speedometer Tone Wheel - 49 Spline (25902)

Fits

This is a replacement rear output speed sensor tone wheel for GM transfer cases with a 49-spline mainshaft; NP261HD, NP263HD, NP261XHD, and NP263XHD. 

The speedometer in your ride picks up signals from the speed sensor's magnetic pickup interacting with the peaks and valleys of the tone wheel, all to keep track of your vehicle speed. But if there's a glitch in the signal, your transmission might go into "limp" mode to avoid further issues.

Part Number: 25902

• Replacement rear output speed sensor tone wheel
• For GM transfer cases with a 49-spline mainshaft
• High-quality

• RTV Silicone is needed to seal the case halves when reassembling. 

Which direction does the tone wheel face when installing it in the transfer case?

 The tone wheel has a stepped edge on one side, be sure to position the wheel so that the stepped edge faces the transfer case pump. 

Do I need to replace the speed sensor too? 

If the tone wheel was damaged from making contact with the speed sensor both will need to be replaced. Carefully examine the speed sensor to verify if any contact has been made and if there has the sensor should be replaced. 

What fluid should I use in the transfer case and how much is needed?

MA Recommends Performance Transfer Case Fluid for use in ALL transfer cases and has seen improved performance over the factory-recommended ATF or other alternate oil recommendations. Two-quarts are required to fill the NP261HD, NP263HD, NP261XHD and NP263XHD transfer cases

I hear a grinding noise at low speed after reassembling the transfer case. What could that be? 

A low speed grinding noise is most commonly caused by the rear output bearing snap ring not being fully seated causing the bearing to move out of proper alignment. Verify that the snap ring is fully engaged and properly seated in the rear housing and the locating groove in the bearing. 

What would cause a speed sensor correlation code after reassembling the transfer case? 

A speed sensor correlation code is often accompanied by a low-speed grinding noise and is frequently caused by the rear output bearing snap ring not being fully seated causing the bearing to move out of proper alignment. Verify that the snap ring is fully engaged and properly seated in the rear housing and the locating groove in the bearing.