need help with speedometer

need help with speedometer

tn trooper

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Location
dover tn
Vehicle(s)
1985 cj-7 304 v-8 3 spd. dana 20 t-case.
my speedometer quit working I recently put a AMC 304 and 3 speed in my jeep and when I was done the speedometer worked fine. now it doesn't work so I put another speedometer cable in today and it still doesn't work. What else could it be is there a speedometer gear that could've went bad any ideas? please help.
 
It is possible for the gear to slip on it's shaft but it will move something enough to at least make the speedometer jump. what transfer case do you have?? the Dana 20 has a hex head that you can find if you dig deep enough and will screw out to be checked.:cool:

my speedometer quit working I recently put a AMC 304 and 3 speed in my jeep and when I was done the speedometer worked fine. now it doesn't work so I put another speedometer cable in today and it still doesn't work. What else could it be is there a speedometer gear that could've went bad any ideas? please help.
 
If you have a Dana 300 the gear is in the hole where the speeds cable goes, just reach in and pull it out. If it still looks good than cheepjeep is probally right.
 
ah just noticed your not from around here so that won't work. we'll help the best we can anyhow :D:chug:
i'm not that familiar with the Dana 20 i have a Dana 300 , but i can tell you i replaced the cable on mine and checked the gear in my Transfer Case and it was all good, my speedo just jumps around so i know its took a dump. once you eliminate the speedo gear, and cable there isn't really anything left to check you just have to assume your speedo is bad. and they hurt your wallet to replace about $100.
 
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thanks everybody, I'm in the Nashville district so we didn't have one but we do them a few times a year just focusing on commercial vehicles it's something the federal government has us do since all TN Troopers are level 1 truck inspectors now that they did away with the DOT
 
I don't think my speedometer is bad although it could be it always worked fine very accurate no jumping or bouncing but it doesn;t move at all. So on the Dana 20 do I just screw the nut where the cable goes into it at out and that's the gear?
 
dig around on the stub out that the cable cap screws on to and you will see the hex head. Put a socket on it and thread it out. at one time the gear on the shaft on my 77 Dana 20 started slipping, it is apparently just pressed on. I put lock tight thread locker on it between the two and let it set up, it worked and that was a long time ago.
Not going to promise this is your problem but it is worth a look. It shouldn't take too long to pull the gear.:cool:
 
If what Iport said don't work
Try disconnecting the cable from Transfer Case
hook it up to a drill see if speedo moves, if it don't cable may be broken inside the casing or a bad speedo , I have a dana 18 same type case as 20 and had same problem wound up being broken cable :chug: if by chance its the speedo itself I have a few floating around just shoot me a pm
 
Anybody have any tricks on how to get the gear out of the Transfer Case . I see the hex head but it's a very tight fit. Is there a special tool or socket that will get it out. I think it's a 7/8 I hooked the drill to the speedo cable and the speedometer still works so I am positive that I have the problem down to the gear in the Transfer Case . HELP
 
it has been a while but I am pretty sure I used a deep well socket or a box end wrench, nothing special. I would clean it real good before I pulled it so you don't get a bunch of dirt in the TC. Brake cleaner, wear glasses/goggles.:cool:
 

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