Not your usual 4x4 question, Encoder motor bypass?
 

I've searched for this but haven't found information for it, so sorry if I am double posting.

I have a strictly off road, trailered 01 2 door blazer, 5 speed 4x4 with a dana 30 SAS on 33s. Front and rear axles welded posi. My tcase will occasionally pop out of 4x4, and I have to mash the 4LO button a million times and rock the truck back and forth to get her to Re engage. I want to bypass this automatic crap. Not sure if it is possible or not, but I want to do something like weld and bracket to hold this baby in 4 lo. Does the Encoder just turn a shaft on the side of the tcase or is it all internal and pretty much impossible to do?

Thanks ahead of time for your thoughts and experience

Yes, the encoder just turns a shaft to move between ranges/modes. I am assuming that you have the 3-button NV233 transfer case, not the 4-button NV236.

I have seen people weld a wrench to the shift sector shaft (what the encoder motor moves) on the t-case and cut a slot in the floor to allow for manual operation. The thing you have to be careful of with this approach is putting too much heat into the shift sector shaft and melting the seal.

If all you are interested in is holding it in 4LO, then I would just pop off the encoder motor and fab up a bracket that clamps on the shaft and uses one or more of the encoder motor bolts to keep it in 4LO. The shift sector shaft has a double-D (two flats) shaft which can be fun to machine out by hand, but a 9/16" or 15mm wrench would fit just fine.

What I would recommend is disassembling your encoder motor to get to the drive plate that engages on the shift sector shaft and welding that to your wrench and/or bracket. I have attached an image showing the insides of the NV233 encoder motor. The drive plate you are looking for is on the right hand side.

Hopefully it isn't a problem internal to the t-case that is causing it to pop out.

Just the information I was looking for, I really appreciate it.

Yes, I hope it is not a problem internal to the tcase. If so, I have a 96 4 door auto blazer 4x4 parts truck. Would the tcase from that bolt up the same for my 5 speed?

when i did my s10 sfa swap, a np208 from a k5 blazer bolted right up to the 4l60 transmission with no issues. only problem is thats a passenger side drop transfercase. i wonder if a case from the early 90s chevys with the np241 if that would work? i think they are driverside drop.

but with the np208 i was even able to use the floor shifter as it bolts to the actual floor

Attachment 30725

If it comes down to it, I will change out my tcase and find a front axle with the matching drop when I change to a d60. Thats some time in the future thoug, got a wedding to plan and pay for. Definitely some stuff to keep in mind though. I do love how pretty much any chevy drive train bolts up and you can mix and match