Speedometer problem

[FShwiller]

My speedometer quite working. I've checked the pinon gear, transducer, and sender all appear to be ok. Is there a method to test the sender?

 

[BHiggins]

Speedometer

Mine quit a few months back and it turned out tp be the "gear reducer" on the side of the transfer case. The Cummins engines don't spin as fast as gassers so the gearing is different in the trans and usually the diffs too. To compensate, Dodge put gear reducers on the speedometer output shafts which the cable or sending unit screws into. I removed mine, drilled the rivets out (very easy to do) took the gears out and determined one of the gears on the center cluster was just spinning on the shaft. I actually fixed it with Gorilla Glue (after cleaning the parts thoroughly) then re-assembled the unit using small screws. It was only meant to be a temporary fix but it's been working fine for 11,000 miles. It may sound hard but it was quite easy, nothing will "pop out" when you dis-assemble, and it can only go back together one way because the gears on one side are bigger than the other. Hope this helps

 

[BushWakr - RIP]

I moved this post here for better/proper exposure to the full group.

The "Discontinued... " Forum is more for posting a part that is not available or VERY hard to find along with possible sources for that part.



pb... .

 

[mysteryman]

testing

the sender is a magnetic micro switch . as the magnet poles pass over the switch it goes off on off on... . Just like flicking the hall light swith in your house.

Use an ohm tester and spin the shaft with your fingers. As it turn it willmake then break the connection... . If not check the gears. if gears are ok buy a new sender.....

My speedometer quite working. I've checked the pinon gear, transducer, and sender all appear to be ok. Is there a method to test the sender?

 

[rlyons]

Mine quit a while back and it was the gear slipping on the output shaft from the transmission. It is held in place only by side pressure from tightening the output yoke and has spacers on both sides of the gear. A local transmission shop here gave me some washer type shims to place on each side of the gear which tightened the gear to the shaft. It has worked fine since then. Drove me nuts until I found the gear slipping on the shaft.

 

[mazdarotary]

Mine quit a few months back and it turned out tp be the "gear reducer" on the side of the transfer case. The Cummins engines don't spin as fast as gassers so the gearing is different in the trans and usually the diffs too. To compensate, Dodge put gear reducers on the speedometer output shafts which the cable or sending unit screws into. I removed mine, drilled the rivets out (very easy to do) took the gears out and determined one of the gears on the center cluster was just spinning on the shaft. I actually fixed it with Gorilla Glue (after cleaning the parts thoroughly) then re-assembled the unit using small screws. It was only meant to be a temporary fix but it's been working fine for 11,000 miles. It may sound hard but it was quite easy, nothing will "pop out" when you dis-assemble, and it can only go back together one way because the gears on one side are bigger than the other. Hope this helps

I had this exact same problem with mine a few months ago,and I fixed it the same way. I actually tried going to Dodge to get a new reducer,but they were no help(big surprise),and I tried the gorilla glue idea(I don't think I had gorilla glue though). It has been holding up just fine,but I wonder now if I should have used more than just spray white lithium grease in the reducer. I wonder only because there seemed to be something different in there when I took it out. FYI my reducer didn't have rivets holding it together it was screwed together with three phillips head screws. Good luck,and keep us updated.



Chris

92 D250 Club Cab NV4500

83 Mazda RX-7 limited edition soon to be parted

79 Mazda RX-7 Spark Yellow GS "the new project"

74 Mazda RE/PU lawn green w/factory AC

 

[BushWakr - RIP]

You know, speedo problems seem to be cropping up alot lately... . I also have speedo trouble... after key on, the speedo needle will slowly work it's way all the way around the guage until it pegs out at the bottom... .

I've tried replacing the VSS with a new one, which by the way fixed a similar problem about a year ago but this time, no luck... ...



Maybe we need a "dedicated fix" thread for this type of problem since knowing your vehicle speed can be a good thing when you have "dedicated police" in your area... .



What do you guys think..... start a thread and then list the problem and you process of finding and fixing it... . ????



pb... .

 

[jbolt]

... . I also have speedo trouble... after key on, the speedo needle will slowly work it's way all the way around the guage until it pegs out at the bottom... .



pb... .

Hey PB you sure it's not a problem with your right foot?

 

[Greenleaf]

I have info for them who need to send the speedo head off to a rebuild facility. Thinking there are two companies who perform said work. I'll have to look in my LONG list of subscribed threads... ... ... ... ... ...





GL

 

[mysteryman]

electronic speedometer problems ^%$#@!

I have a rather unusual problem ..... I have one that is reading way to fast !

Like at 40 mph real speed it reads over 100... ... and yes I do thave the correct size gear in the trans... ... Has anyone else had this happen to them?



These speedo's are going to be a real problem in years to come!! I think we might as well start planning on having to convert them to cabel driven in the future... . The heads on the electronic ones are made out of plexiglass... . Most of the ones I have taken apart to fix have crumbled when I took the screws out..... jesus chrysler ! what a pain!

You know, speedo problems seem to be cropping up alot lately... . I also have speedo trouble... after key on, the speedo needle will slowly work it's way all the way around the guage until it pegs out at the bottom... .

I've tried replacing the VSS with a new one, which by the way fixed a similar problem about a year ago but this time, no luck... ...



Maybe we need a "dedicated fix" thread for this type of problem since knowing your vehicle speed can be a good thing when you have "dedicated police" in your area... .



What do you guys think..... start a thread and then list the problem and you process of finding and fixing it... . ????



pb... .

 

[Paychk]

mysteryman do you have one of these ratio adapters on your transmission?



#ad

 

[ESchoon]

Speedo Prolbem Also

The speedo on my 92 D350 is reading 10 mph to fast.



I was wandering if mysteryman ever found out his prolbem??



Thanks,



Eric

 

[jrjuday]

Don't forget to check the square shaft thqt drives the VSS. If it gets rounded off the speedo will quit.

 

[Moab4x4]

Alan, I like the grease zerk on your adapter. My original froze up and broke the part off that goes in the xfer case. I ended up buying one from a place I found on the net. Just search 'Speedometer Ratio Adapter". I got mine from

http://www.transmissioncenter.net/727Transmission.htm

about as cheap as anywhere. They have the greaseable kind as well.



Mysteryman,

I had mine to to 100 MPH down mainstreet as well before it died completely. It would have been a blast if it had been real. It was the VSS going out on mine. Voltage supply problems that I don't have worked out yet I'm thinking now. After I rebuild the engine :{ I will work on a fix for the electronics of the speedo. The VSS gives a digital signal to the head which then appears to convert it to analog to drive the speedo head. If you have a bad connection on the VSS that could be causing noise that the speedo head reads as speed impulses, then that could cause the 100 mph. I need to perform an autopsy on some electronics before I can give any better information or a fix. I will post what I find out but it will probably be a while yet.



Ken

 

[JVittetoe]

mine works off and on. and just recently the milage guage quit, but speedo still works half the time.



jeff,

____________________

jeff

92,4x2, D350, manual trans, 200500 showing?

 

[DieselBuzz]

Hey Pastor!

I like the idea of the "Fix the speedo thread. " Mine works fine around town but on my 2hr. highway rides to NH it's irractic. Some trips it works, others it dies after 15min. others it's on and off. I'm guessing mine is an electrical connection that heats up and opens up. Once I get home it's fine again,(that's why I haven't fixed it,yet. )

I think it would be great to centralize everyone's experiences in once place so we don't all have to learn the samething by ourselves. This is what ties me to this web site and makes my subscription worth every penny.

Thanks and

Happy Holidays to All

 

[DieselBuzz]

So I just did 500 miles over the weekend and the speedo was fine. I wish complaining about things would fix them every time!

 

[Moab4x4]

VSS guts

Here are the guts of the microswitch that mysteryman was talking about. I would have sworn that they would have used a hall effect probe, but the RPM's must be too slow or something. The fuzz on the magnet is iron filings that I used to indicate the magnetic fields of the 8 magnets in the disk.



BTW I bought a new VSS and tried the multimeter test, it failed and so did the replacement that I bought. I am working on a different test. Maybe I am just lucky with the ones that I buy. Mysteryman, how did you fix yours? Greenleaf, could you post or PM me the speedo rebuilders sometime?

Thanks,

Ken

 

[Why Not]

I just ran into the same problem on my truck. After taking everything apart I found out that my speed sensor was bad, and also the gear reducer had went bad after 229848 miles. This all happened as I was in the process of changing gears in my truck from 4. 11 to 3. 54. After doing the gear change I went to the local dodge dealer and with a little looking I went home with parts I needed. They carried the speed sensor and gear adaptor on the shelf and was happy to help. The speed sensor part number is 1-05252438 and gear adaptor for 3. 54 gears with a 14 tooth speedo gear was 4348801. My speedo is not back up and running and also correct.



Why Not (Chris)

 

[MXTMOPR]

Rounded off pin (Exploded View)

The pin in the ratio adapter became loose and spun inside the gear in the adapter. Completely disassembled view shown. Just grab the 4 sided shaft and pull, clean the end and the hole in the back of the gear, put some JB Weld on the area that has been rounded off, and re-insert into the gear. Let this cure for several hours before re-lubricating and putting back into service. Speedo works again!!!