Speedo not working

[scottyknows50]

Put on a new cable, turn the cable with a drill and the speedo turns just fine. Hook it up to the transfer case and I get nothing when I drive. It looks like it has some sort of adapter on the transfer case- anyone know what it might be? I now assume this piece to be the problem. It's dark now but if you need a pic of the adapter I should be able to get one during daylight. Thanks.

 

[bigcountryguy19]

Could be the adaptor, or one of the plastic gears inside sheered the teeth off.

 

[chengny]

Not mentioned is the model no. of the transfer case.

Here is a shot of how the cable mounts on a NP205

 

[chengny]

An NP 208 has that adapter plate that is indexed to match the number of teeth on the gear.


Look at the gear holder housing. It should have an off-center hole for the gear, so it has to be inserted with a specific "clocking", as there are different gear diameters for different tooth counts. You read the numbers on the side, match that to the tooth count you're using and that mark lines up with the mark on the case. If this is wrong, the spacing between the drive and driven gears is wrong and could lead to premature failure (or a non-working speedo). You'll see that the little hold down tab can hold the housing in different orientations.

Some visual aids:

 

[scottyknows50]

Here's a pic of what I have going on underneath:

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Looks like the 205? Would someone add this for bigger tires/different ratio? Anyone seen one like it before? Thanks.

 

[chengny]

Does that adapter have an electrical lead?

 

[scottyknows50]

No wires to it. I took it off and the cable still didn't work. I thought I read that there was a gear that breaks in the transfer case that drives the cable. Guess I'll have to search for that. If anyone can point me in the direction of a "diy" it'd be appreciated.

 

[chengny]

Read about the procedure here:

http://67-72chevytrucks.com/vboard/showthread.php?t=316337

 

[towjoe]

the adapters are common to round off the input shaft going in them. replaced many of them. last one was bought at dealer and like $35