4940C tachometer

[Stampeder]

After almost 700 hours on my 4940C my tachometer is acting up.
When the engine has been running for a while at over 1500 rpm, the tachometer will take off and pin itself. The only way to stop this is to shut the engine down and restart. I took the cable off at the tach in the dash and put dry lube on it.
I have seen this behaviour before on other mechanical tachs when the cable was wearing and about to break but I think this one may be the tach itself.

Has anyone else had this happen?

Who would be carrying a tachometer?

Glenn.

 

[Texasgreen]

My 2006 4940C has 760 hrs on it. My tachometer has stopped working also. Mine stopped working around 750 hrs I noticed. I haven't pulled the instrument cluster to look and see what's going on it yet. I'm sure the cable has broken.

 

[Stampeder]

My 2006 4940C has 760 hrs on it. My tachometer has stopped working also. Mine stopped working around 750 hrs I noticed. I haven't pulled the instrument cluster to look and see what's going on it yet. I'm sure the cable has broken.

I found the end of the cable at the tach had loosened so I tried giving it some dry lub and reassemble. No luck though. I too suspect a cable problem and not the tach. I've asked for a quote for both from my local LS dealer but haven't heard back yet.

Glenn.

 

[Stampeder]

Update to my tach problem. I took my dash apart and opened up the tach. I suspect what was happening was a bit of dirt had got in between the two spinning parts of the tach and caused them to get locked together. The spinning disks act like a speed reducer from the cable to the point of the tach. So when the dirt got logged between then it would cause the pointer to pin to the right.
I then cleaned everything up and reassembled it. I further removed the tach cable and lubricated it with spray on graphite.
So far everything is working just fine. I shredded my5 acre field for about 3 hours at about 2300 rpm and the tach behaved very well.
For those with a broken tach cable, fixing it is a piece of cake. You remove the engine end of the cable, pull the cable out, insert new one, remember to twist it until it indexes into the drive at the engine end. It's really a 10 minute fix.

Glenn.