Tachometer and hour meter not working

[RMJ22]

This is regarding a 1999 Deere 4100. Bought the tractor used and tachometer has never worked. FYI, the hour meter does not work either. I took off the cowling today and looked and the cable appears to be properly connected in the back of the gauge as well as at the engine - took it out and put it back in at the gauge and made sure it was tight. What should I check next?I know this shows my ignorance, but is there any way maybe something like a blown fuse, or some other simple device they could have in common, would have anything to do with something like this? Thanks in advance for any help!

 

[billybobjimmyjoejack]

On my tractor (Ford 1715) the hour meter stopped working (tack was fine) and I researched having mine repaired. A local speedometer shop was familiar with the gauge and told me that one of the gears that drives the hour meter was probably worn out. The cost to repair it if they could find the parts was going to be almost the same as a new gauge.
I bought a new gauge and took the old one apart and sure enough one of the gears was worn out.
I was told the reason for the high cost of repairing the gauge was that the case is almost impossible to open without damaging the whole unit, so it becomes a disposable item.

 

[jd110]

The tachometer is strictly mechanical. No electricity is involved with making it work. When you disconnected the cable from the back of the tach, did you start the engine and see if the inner cable turned? If it does turn, then the tachometer is bad. If it does not turn, then either the cable is broken, or the drive mechanism on the timing cover is bad.

 

[RMJ22]

Billybob - I'm thinking I might have the bad gear problem like you mentioned. Do you think if I bought a new one I could advance it so the numbers match before I put it in?

JD110 - Thanks for the tip. It will be a couple days but when I take it apart again I'll report back. Hopefully just the gauge is bad and I can just replace it because the timing cover is uncharted territory for me.

 

[billybobjimmyjoejack]

One of my brothers worked in a speedometer shop years ago and he would have to repair odometers that guys tried to change and he could do it, but it was tricky. There was a special combination of moving the wheels of the odometer so you would not damage the gears. The newer gauges might not be as easy.
I just installed the new one and I am keeping the old one. If I ever sell the tractor the old gauge will go with it.

 

[Tx Jim]

RMJ22
If you look at the prices of each part you may change your mind about hoping it's the gauge. You didn't state which type trans so part # I posted for panel could be wrong part #

AM875580 GEAR UNIT ASSEMBLY, TACHOMETER ADD 46.56 USD
AM879484 PANEL, COMP. ADD 686.40 USD
LVA801320 CABLE ASSY, METER ADD 50.72 USD

 

[RMJ22]

May not be anything I can do w the hour meter but replace then. And Jim, thanks for the prices. Mine is the hydro model. And if you don't mind, what website did you pull those figures from?

 

[Tx Jim]

JDparts.com To get prices one must signed in with a particular JD dealer. I made a good guess and the part # AM879484 is for a hydro tranny.

 

[Brimstone10x]

the tach drive cables do break .its not uncommon. the gear drive breaking would be rare .

 

[RMJ22]

Hoping to break back into it Saturday morning. . .if I do have to replace the cable or the mechanism on the engine-side of the cable, how hard is it? Looks like the alternator may be in the way - will I have to remove that?

 

[RMJ22]

Well, I broke into it today and the cable is broken!! Hoping thats all that is wrong with it. I didn't have to take off the alternator afterall to get to the 90 degree knuckle where the cable ties into the engine; it was a tight fit but my hands are kind of small so it worked out. Will post again when I get the new cable installed.

 

[RMJ22]

The new cable fixed it!!! On a side note, it worked great for about a half hour, then started burying the needle if I went over 1500 rpms as well as making a high-pitched humming sound. So I put some more grease on the end of the cable that goes into the housing and then the needle started bouncing. I put a little more grease, let it run and now it works like new!

 

[rsewill]

Thanks for reporting the fix! Not everyone does. BTW, I have a 4100 so your report may help me out someday.

 

[jenkinsph]

When you are fortunate and get a reply from jd110 you should heed his advice. I have been around here for a few years and both Tx Jim and jd110 are usually spot on. I would like to know what these two guys' have forgot.

 

[Tx Jim]

. I would like to know what these two guys' have forgot.

Flattery will get you NOWHERE. :laughing:
I can't speak for jd110 other than I know he knows JD's but for me at my age of 67 I've forgotten a lot!!!!!!!!!!!!! Especially considering I left a JD dealership to custom bale hay in '87.