opt np4

burg99

Original poster
Member
Dec 23, 2012
33
Does anyone know what this option is on the transfer case opt np4. I need a new encoder motor and im not sure what this is. Also, where can i find weather or not i have this option.

Thanks
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Welcome! If you filled out your vehicle profile I could have answered this in one pass, but NP4 is the AWD transfer case used in the Bravada and other vehicles that did NOT have a LO range and a mode control switch on the dash.

NP8 is the full-function transfer case used in the Trailblazer and Envoy with a LO range.

If you have a TB or Envoy, you need the encoder motor for the NP8 transfer case, also sometimes known as the NVG226, which has 7-pins in the wiring harness to the encoder motor. The NP4 unit is the NVG126 and its encoder motor has only five pins.
 

burg99

Original poster
Member
Dec 23, 2012
33
Roadie,

I have a 2003 olds bravada i have no selector switch on the dash so does that mean i need the encoder motor without the np4 option.
 

burg99

Original poster
Member
Dec 23, 2012
33
Roadie,

Its my last option before i take it to the shop. I have no awd no lights on the dash either. Transfer case oil is good and changing the right front wheel bearing for erratic or missing wheel sensor did not help.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
An independent shop with a high end scan tool or a Tech II (non-dealers can own them) could talk to the TCCM and command the encoder motor through its paces and narrow it down for sure. For less than the cost of the encoder motor. It could also be wiring to the motor. Or a simple internal problem in the motor like another member just repaired himself when a chunk of permanent magnet broke adhesion to the case probably from being malleted. Just want to minimize your frustration in case the motor swap didn't cure it.
 

martinr1956

Member
Dec 27, 2013
2
Hi roadie,
I bought a 2002 Bravada spring 2012 and it ran well for about 13 months when I started having crow hop when backing and when turning. I did some research and replaced the encoder motor, problem solved. I replaced it with a new Dorman motor. Fast forward around 3 months and I get the same failure; crow hop under the same conditions. When I purchased the Bravada, I did a ton of work including changing the transfer case fluid with the genuine GM product. But, just to make sure I replaced it again (no help) before changing the encoder motor for the second time. I returned the motor to the store and got the replacement under warranty. Once again, the problem is solved and the truck has been operated in both dry and slippery road conditions for about another month and a half with no trouble yet. So, what do you think, just a defective encoder motor or an underlying transfer case issue? I appreciate your insight. Thanks.

Other recent work includes replacing both front wheel bearing assemblies; one for wear and one for defective speed sensor that caused anti lock break actuation. 106k miles
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
I'd say 50-50% chance of either scenario. But I have very little data to go on. When you first replaced the TC fluid, was its volume and color right? Any debris in the fluid that could have come from clutch material? What was the maintenance history? When you bought it, if it didn't come with a good maintenance history, did you change all fluids right then? What's the situation with the front and rear differentials, which should have been changed at 100K? Does your glovebox RPO sticker have the code "G80" for the automatic rear diff locker?
 

martinr1956

Member
Dec 27, 2013
2
Thanks for the quick reply! There was no maint history prior to 80k miles. I am the third owner. I did change the rear diff oil and checked the level of the front diff. The transfer case fluid was discolored but no debris in it and as I recall the volume was about right. The second time the fluid was changed it was clean and blue. The G80 code is listed.
I have already put more mileage on it than I had with the first encoder motor so I am keeping my fingers crossed!
 

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