Speedo Pinion Help

[The Octopus]

Alright, I'm going to ask what is potentially a very stupid series of questions. I appreciate anyone who's willing to bear with me. I'm not really used to working on cars, so I'm bumbling my way through this '68 4-door 510 that I picked up which has a stock L16, tranny, and rear diff.

 

The previous owner said the speedo did not work because it needed a speedo pinion. I assume this pinion sits at the end of the speedo cable on the driver's side at the rear of the tranny. In discussing with a few 510 owners, it appears that my best option for determining how many teeth I need on the new pinion is to count the teeth on the gears. Is this true? For some reason that doesn't seem quite right.

 

I unscrewed a retaining nut on what I assume to be the end of the speedo cable and saw that the cable was still firmly attached to the inside of a threaded assembly going into the tranny. How do I go about removing it and disengaging the cable so I can replace just the pinion? Do I simply gently pull it out with a pair of pliers, or do I need to unbolt and remove something else first?

 

There are a few NOS pinions available on eBay right now, but are there alternative sources as well? I'd like to be able to get the speedo up and running since the '68 is mostly original inside (minus a huge tach the PO installed, which must be replaced).

 

I've done a search on here and mostly find people discussing which teeth work best with different powertrain components. My questions are even more rudimentary than that, which I think speaks volumes about how poor my knowledge of cars is.

[Braden]

this is a goo dquestion for datzenmike! i dotn knwo about some of the 510 trannys, but both the 4 speed and 5 speed trannys i have worked on the speedo cable has a threaded ring used to keep the cable into the side of the tranny, unscrew the ring and it should pull out, maybe the 68 is different? i would assume so judging by the description you have given? mike will chime in with good advice and pictures to back itup any second now!

[datzenmike]

It's much more likely that the cable is broken than the pinion that drives it. Below is a speedo outer sheath (left) with the flexible inner cable sticking out. On the end is a ferule that is crimped on that goes into and engages the pinion drive. (right) This is not from a 510 so it won't look exactly like yours. The inner cable end can only go in one way and it locks in position. It should pull out easily.

 

 

 

 

You can pull the inner cable out of the outer sheath to inspect it for damage or dryness. It is (or should be oily and slippery) so have some rags to collect it with and to keep it from getting dirty. If the cable is broken the end will be twisted off or frayed and obviously broken. The fix is to replace the entire assy. The far end should be squared off. Here is one when looking from the dash end but you can see the square shape.

 

 

Well if the cable is fine and the needle jumps when turned the only other thing is the drive pinion.

 

Your drive pinion should look similar to the one below. It is held in place and alignment with a keeper that fits a slot in the side and held down with a 10mm bolt. The alignment is critical, so the pinion must be removed or installed in that position with minimal twisting or the plastic gears will be crushed against the steel drive gear inside. Try to wiggle it loose and pull straight out. I have used vice grips on the shoulder just above the threads and near the key way slot but have a cars that the threads not be damaged. Alternatively, you could install the cable and tru gripping it by hand and pulling.

 

Your pinion will look roughly like this one and only have the one slot. This has been modified for another transmission.

 

The plastic pinion gear can be removed from the housing or sleeve and replaced but likely it will be easier to find someone with a spare tranny left over from a 5 speed swap that you can get a replacement from. The gears are color coded and the 510 used either a 16 (Yellow), 17 (Black) or 18 (Blue) tooth cog depending on differential gear or tire size options over the years. They may still be available from Nissan for under $20.

 

Again these are for example only.

 

 

 

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[Braden]

see what did i tell ya!!! i learned something too! i can take out my cable inspect it clean it re lube and re assemble it! sweet man!

[datzenmike]

For a lube avoid conventional oils like 3-in-one and look for a dry graphite 'powder' or a 'grease' containing molybdenum disulphide in it . Examine the outer sheath for previous kinking or outright damage as it can allow water/dirt in. Water will cause rust but worse it will freeze in the winter and the cable will snap if it can't turn freely.

[The Octopus]

Damn. Great job. Thanks so much guys.

[banzai510(hainz)]

the Pinions are made of plastic in case that jam up and design to shear.

If tyou need one just get one from antyoher datsun member thats going to trow a 4 speed away.

 

I dont know if Nissan still sells the part

Most times the cable is just broke inside the cable housing