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Speedo Issue

1K views 23 replies 9 participants last post by  Rino1425 
#1 ·
I have a 93 YJ with the I6. When i first got the jeep a few months ago, the speedo was not working at all. I pulled the cluster, and cleaned all the contacts and checked to make sure the ribbons were broken. All checked out good. Now, when i drive, the harder you press the pedal, the speedo moves. Yes, i understand that is what it is suppose to do, but i can floor it in first and it will go all the way to 100, then let off and it drops to zero. Its almost like its getting a signal from something else. Any one ever have this issue or know what to do? Also, when driving, it just "bounces" around like 20 to 60. Like its takes its reading off how much throttle input i am giving it. ie. it goes to 20 when i give it 20% throttle.

Thanks,

Jon
 
#7 ·
I had a speedo issue one time, my junk was too big to wear one! lmao!

Seriously, my speedo wouldn't work at all. Pulled the speedo out & put a drill on the back and she ran up fine. Disconnected at the xfer case and did the same with the drill and again ran up fine. Thinking the square shaft inside the speedo cable looked too short at the xfer case end, I ordered a new cable, installed, and nothing. Ended up finding the speedo gear hold down tang was upside down for my size gear so the plastic gear was not making contact within the xfer case.. Rotated it 180* and she runs up like a champ.
 
#11 ·
There was a thread a while back in which someone else had the same issue. One way to test it that was mentioned was using a drill on the end of the VSS while connected tot he harness and watch the speedometer. If it is still twitchy I would think that it is the VSS itself.
 
#13 ·
In the pic below you can see the slots machined into the transfer case speedo output with the fork aligned into a pair of those slots. The speedo output is off center in that component to accommodate different size gears within the xfer case. Unbolt the fork and rotate the output 180* and tighten the fork back down. This will rotate the speedo gear inside the xfer case into position. My gear had '30' on it also and it was just a matter of it being installed 'upside down' by the PO.
 

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#15 ·
Nah, those marks that are a few degrees from where it is at now are from the PO's 'mechanic' torquing down on the fork without it being in one of the slotted grooves.....he made his own set of slots for me to figure out were not part of the original design.

Sounds to me like you need to replace the VSS.
 
#17 ·
So still working to figure this issue out, but while browsing quadratech today, i noticed something. They sell a "long shaft" speedo gear for the cable driven speedos. I am not sure if the transfer case i have is the original or not, but is it possible that it was set up for a cable drive and that is why its not working?
 
#18 ·
Transfer case is the same regardless of cable or electronic speedometer cable. You said that the drill test worked, that leads me to believe that either your gear isn't clocked right or your drive(n) (can never remember which is which) on the output shaft is broken. Did you look at the output shaft through the mounting hole for the VSS and look at the gear there?
 
#20 ·
#22 ·
If there is no difference between cable and electric, why is there different parts? Quadratec calls out a longer one for cable driven.
Jeeps from 1955-1992 used a speedo drive gear with a longer shaft design, and 1993-newer models use a shorter shaft design.

Although the speedo drive shaft design changed, the transfer case housing did not change.

Max
 
#23 ·
I retract my statement regarding the longer one. After looking at the post Max, i will take everything back apart and measure. I can tell the transfer case has been taken apart at some point. I will also try to get a picture of the output shaft for you guys to look at.
 
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