Alright i got a 92 cummins 5spd(getrag) with the np205 case the whole powertrain and wiring was working in the previous truck took it all out and everything in my dash works except my speedo. Tried a friends nothing, tested the speedo with the vss out of the case rolled it and the speedo would jump ok, checked the gear in the case looks great put it back together tried again nothing. Any ideas? I havent tried testing the ohms i didnt know what they should read or where to test i looked in the sticky but couldnt find anything that was similar related

 

did you check the wires in the VSS plug? I know it sounds like a dumb question but I have stuff like that happen.

 

The speedo pinion adapter has to be clocked correctly. If you look on the adapter is has numbers on it that correspond to the number of teeth on the pinion gear. The gear is also marked with the number of teeth.

 

I did not check the plug i did clean it and tried seeing if the wires were loose but that was it.

Could you by chance take some pics of where the numbers are and clocking it?

 

The w250 comes off the transfercase and doesn't need to be clocked line the 2WD. Too bad, that would be an easy fix.

 

Yes, I remember now, it has the adapter box. Does the transfer case output shaft have a plastic gear on it?

 

Yes inside the transfercase it dors have a plastic gear. I tried 3 different vss from ither trucks and also tried a different speedo gear the one that goes into the transfercasethats metal from another truck

 

Would iy be possible to use a mechanical speedo from a gasser with a np205 and just use everything from the vss down?

 

Anybody have part numbers on worm gears thinking this could be a problem

 

There's a sticky with "fix your odometer" as the subject.

 

The plastic gear in the transfercase i looked through the sticky no part numbers only guys talking about getting them

 

Shows you how good my memory is.
I can't help you further, but hopefully others will chime in.