Quick question

[Sick720]

I have a 83 720, and i have gear oil coming through the speedometer cable. What could be the problem, vent cap plugged?

[Sick720]

Any help would really be appreciated.

[darrel]

There is a seal in the spdo carrier, there is also a plastic washer at the end of the cable casing.

[datzenmike]

There is an O ring around the speedo drive pinion but that's to prevent oil leaking out under the vehicle. The speedo cable has a top hat shaped 'rubber' cap that prevents oil from being augured up the spinning inner cable. I've looked for the part number before and I think it's only found by buying a complete speedo cable assy. You could probably make something from a thin sheet of neoprene. Poke a small hole and slip on from the other end. Just unscrew the cable at the tranny and the inner cable will slide right out. Have a care it's very limp and slippery.

 

[darrel]

Forgot about the oring, but that's pretty obvious. There is also a seal deep inside where the pinion is.

[darrel]

Here's the seal inside the carrier. You would need to remove the cog and use a hook to get the old one out.

 

These are the only number/letters I could make out.

nok

1330

ago241f

 

The cog shaft measures 9.92mm

 

OD of seal 15.92mm- 15.95mm

 

 

Here is a thread on nissan diesel with part number. 

 

http://nissandiesel.dyndns.org/viewtopic.php?t=2492&sid=9a84a86541769b82448fc3004b30cef4

[CWhip]

Sometimes the speedo cable isn't screwed in all the way and it will leak. 19mm wrench and snug it up.

[datzenmike]

Go easy, it's die-cast pot metal and won't take much abuse.