John Deere 2520 Tach problem

ecr64 · Jan 8, 2016

Hi all,
I have a 2007 JD 2520 that has 420 hrs on it that has been working perfectly for my light duty work on my 2.5 acres. Recently I am having a problem with the tach and wanted to know if anyone has experienced a similar problem and hopefully can recommend a fix. Every now and then, the tach needle on the display goes all the way to the max hard stop and I hear a high pitch "squeal". Throttling back does not affect (or correct) the situation. If I turn off, and restart the problem goes away for a while and then comes back after some time. Any thoughts? I haven't looked under the instrument cluster yet to check if something is loose, but that's my next step.
Thanks!
-E

davesl708 · Jan 8, 2016

I would start with the loose connections. Don't forget to check the ground wires. A loose ground can cause strange readings on instruments.

Texasmark · Jan 8, 2016

Loud squeal of a rotating shaft/instrument sounds like a dry bearing to me if mechanical. If electronic, I'd go with the loose connection Dave mentioned. If you loose ground on electronic circuits, no telling what they will do. A sloppy fitting connection could be doing just that as the shield on the cable/connector is usually part of the ground circuit.....I suppose.