Speedometer Questions

[GTX.JCW]

This is a Howzit Work question..

I understand the process of the gearing in the transmission that rotates the cable that moves the indicator.

My question is; are there any other gears that affect the reading of the speedo.
Mine acts like it has a doubler in it somewhere. At 35 it indicates about 70. About, because it is bouncing around. New cable is probably in order as I dumped a bunch of graphite lube into the housing and that did not seem to have any effect on the bouncing.

I did have the speedometer gear in the trans changed. The new gear is a yellow 33 tooth. I used one of the web page formulas to determine the correct gear, using tire height, rear end ratio, etc.

Any help is appreciated,



Jeff

 

[lewtot184]

i've had some issues with the old original cables, not quit as bad as yours though. i replaced the cable and now everybody is happy.

 

[YY1]

Bouncing could be lack of lubrication.

I unhook both ends, and pull the center all the way out of the sheath.
Then I run it through a handfull of white lithium on it's way back in.

 

[hunt2elk]

Also make sure the alignment mark on the gear housing is in the right position for the number of teeth on your gear.

 

[ilm65]

Also make sure the alignment mark on the gear housing is in the right position for the number of teeth on your gear.

What he said--very easy mistake to make.

 

[GTX.JCW]

Alignment..

Would a misaligned gear cause a 2x speed reading?! I will admit, this is uncharted territory for me..

I was also advised that it was the speedo itself that was causing the bounce, as the mech that worked on it lubed the cable prior to putting it back together.

Jeff

 

[hunt2elk]

If it is bouncing that badly, something is binding. And it probably isn't off that much but because it is catching and then jumping higher than it should. Does it go down to 0 when stopped? Check the cable for any damage - if none, I would unscrew the end from the tranny. Hook a drill up to that end and see if it is still bouncing running like that.

 

[GTX.JCW]

Bounce

Actually, it seems to bounce between 0 and 30 or so, but when the speed of the car gets to 35 or so, the speedo indicates approx. 70 and fairly stable.

So, I will try the drill trick and see what that shows.


Jeff

If it is bouncing that badly, something is binding. And it probably isn't off that much but because it is catching and then jumping higher than it should. Does it go down to 0 when stopped? Check the cable for any damage - if none, I would unscrew the end from the tranny. Hook a drill up to that end and see if it is still bouncing running like that.

 

[Plymouth_Bob]

jeff im having this same exact problem in my car i put a rally cluster with 150mi speedo and i started getting the same issues you are so i reached under the dash and unhooked the cable and kept driving and observed the cable spinning freely which to me would indicate that the core of the cable may not be the right size for where it plugs into the speedo causing it to catch on a corner and not seat properly hence the binding that was mentioned before, if i get it fixed before you do ill post what i did

 

[GTX.JCW]

I will..

have to follow suit and see what mine is doing!

I would certainly appreciate the info if you figure it out!

Jeff

jeff im having this same exact problem in my car i put a rally cluster with 150mi speedo and i started getting the same issues you are so i reached under the dash and unhooked the cable and kept driving and observed the cable spinning freely which to me would indicate that the core of the cable may not be the right size for where it plugs into the speedo causing it to catch on a corner and not seat properly hence the binding that was mentioned before, if i get it fixed before you do ill post what i did

 

[Cazbah362]

Yes, if the gear holder (part that attaches to transmission) is not on the proper dot for the right tooth count, you can eat up the gear could cause the issues you have - Past experience. Make sure its on the right gear range.

 

[68 Sport Satellite]

I have the exact same problem. It's bouncy up to 40mph, then smooths out after that. Makes intermittent noise too. I changed to a new speedo cable and the problem is still there. I was going to get the speedo itself rebuilt with new updated internals, but maybe that won't fix the problem?