Speedometer Stopped working

[Drstnick]

This is my first time posting. Last night my son and I went for a quick ride before he had to go back to his mom's. About a 1/2 in to the trip I placed the truck into neutral to "coast" down a steep hill. I saw the speedometer start bouncing and then it went to "0". What now? It's a hard to lay down to try to get to the back of the speedometer, guess there's some who have found that out. There's a tight bend in the cable as it comes out of the fire wall before it heads to the back? How do I check the cable? Could it be the gears? I see a grease fitting where it goes into the transfer case, Thank you for your help! I'm in Greenville S.C. Anyone else near me?

 

[BKubu]

Disconnect the cable from the back of the gauge. While driving, have someone look at the end of the cable to see if it is spinning. If it is, it most likely was loose on the back of the gauge or the gauge went bad. Still, I think you have a bad cable and replacing it will fix your problem.

 

[Drstnick]

Where can I get a cable? Do you have a part number? Is the only way to the speedometer from under the dash?

 

[porkysplace]

Where can I get a cable? Do you have a part number? Is the only way to the speedometer from under the dash?

Part numbers are in the parts TM ( TM that ends in -P ) . Got to know what truck you have to even guess at a part number.

 

[steelandcanvas]

About a 1/2 in to the trip I placed the truck into neutral to "coast" down a steep hill.

 

[MO MV man]

My speedo did the same thing.
Assuming you have an M900 series truck, Memphis Equipment has them.
If memory serves me right, it was just under $100 shipped.
That is, by FAR, the longest speedo cable on the planet. LOL
I haven't installed mine yet......definitely not a quick job.

In the meantime, I used the speedometer app on my phone, referenced the RPM's at a few common speeds and put them to memory.

 

[ke5eua]

Part numbers are in the parts TM ( TM that ends in -P ) . Got to know what truck you have to even guess at a part number.

I'm placing my best bet on a 809 series.

I thought the same thing, engine brake it, neutral just asks for to many problems if you need to do any evasive maneuvers.

 

[Drstnick]

I have a 1991 M923A2. So you're saying that putting it in neutral could've cause it?

 

[porkysplace]

I have a 1991 M923A2. So you're saying that putting it in neutral could've cause it?

No he is saying putting it in neutral on a steep hill can cause a runaway truck with no way to control it such as using engine braking.

Edit : You need to download these and save to your computer
[h=3]TM's for the M39 Series 5-ton[/h]And please read this one before driving it it , for your safety and the safety of everyone else on the road ; TM9-2320-211-10.pdf

 

[Castle Bravo]

What I have seen before is the tachometer pulse sensor mess up how its handling the "key" adapter between the injection pump and the pulse sensor. The adapter had fallen out of place just enough to make the tachometer not work correctly.

Even though its the speedometer in this case, I'd take a look at both ends of the cable and look for damage.

 

[CasualPREPER]

This is my first time posting. Last night my son and I went for a quick ride before he had to go back to his mom's. About a 1/2 in to the trip I placed the truck into neutral to "coast" down a steep hill. I saw the speedometer start bouncing and then it went to "0". What now? It's a hard to lay down to try to get to the back of the speedometer, guess there's some who have found that out. There's a tight bend in the cable as it comes out of the fire wall before it heads to the back? How do I check the cable? Could it be the gears? I see a grease fitting where it goes into the transfer case, Thank you for your help! I'm in Greenville S.C. Anyone else near me?

Hey there! I’m sorry I don’t have a solution for your speedometer problem. I have the same issue which is why I’m here researching. I’m in Columbia SC. I’m very new to this site got my M998 very recently with multiple issues that I’ve fixed so far now working on speedometer deal. I mainly wanted to ask you if you figured out a way to get yours tagged for road use in SC and maybe if you know a spot around here to go let loose the beast. Thanks and looking forward to hearing from you.

 

[porkysplace]

Hey there! I’m sorry I don’t have a solution for your speedometer problem. I have the same issue which is why I’m here researching. I’m in Columbia SC. I’m very new to this site got my M998 very recently with multiple issues that I’ve fixed so far now working on speedometer deal. I mainly wanted to ask you if you figured out a way to get yours tagged for road use in SC and maybe if you know a spot around here to go let loose the beast. Thanks and looking forward to hearing from you.

He has a 5 ton not a HMMWV , there is a HMMWV forum to ask questions about your speedometer on your HMMWV. As for registering please read this thread as he has a 5 ton and doesn't have the issues of a HMMWV on registering . [h=1]HMMWV Titling[/h]