Some days its really bad and other days it doesnt do it at all. The needle just drops to zero then climbs back up to the speed I am going. I have noticed that it tends to do it more when im going up a hill. The truck is a '92 D250 with just over 100K miles, so I dont think it is worn out.

Any ideas? All the other guages work fine.

 

Sounds like the speed sensor on the tranny(or the transfer case in the case of a 4wd), I had the same problem and found the speed sensor had a crack in the housing. My speedo would quit and if I gave it a smack it would work good for a while. Finally replaced it with one from my parts truck and haven't had a problem since. Good luck, hope this helps.

 

well i have had similiar problems but the thing is that the speedo stops but the odometer works like a charm, and i think that it is not the sensor or the odometer wouldnt work. and also sometimes it shows im doing 100 when im doing about 50 or so.

 

Real easy to notice while you had the cruise set...bang, all of a suddent it kicks out.

The electrical connection on the t-case would occasionally get either moisture, dust or oil and would become intermittent. Just spray some electrical contact cleaner and reconnect...usually good for about a year or two.

 

My dodge has the exact same problem. It only stops working very rarely. Then about 10 miles down the road it will jump right to the speed I'm going and work properly for many more miles. Not too concerned about it yet.

 

could be the nut on your output shaft is loose

 

Your problem sounds like it's internal to the speedo head.

 

Not necessarily the nut loose on the steering wheel(as in my case)? All seriousness aside, my speedometer has some fits also. But I've only seen it not work right from startup in the morning, and even then, only when not driven for a few days. If driven regularly, never has a hiccup. When it does not register from startup, it has always picked right up to speed(as mentioned above) within about 10mi max and then continues fine - until next time. Once working, it has never failed whilst going down the road(yet). Do you suppose it may just be the VSS drive here? Thanks!!

 

My first 2 gen 1 trucks had the same problems. I found it was not the sensor both trucks. If the odo is working or th cruise is working the sendor is working. Dodge admitted they had a lot of problems with the internals of the dash unit. I had to replace on both trucks at 130k or so. But on the second truck it went out with the new one after another 30k. So I put in a Dakota digital aftermarket. Still running after 5 yrs.

 

Tell us more, with pictures and a good TECH write-up.

Thanks.

 

yes i would be much intersested, im trying to gauge my speed off a crappy tach