I hear a sound and maybe more importantly I feel what seems like the track coming under tension and then releasing. With this feel is a sound like the track gets tight then releases. The machine is a Cat D3G 2005 with just over 2000 hours. Is this the track starting to ride off a roller and then coming back into position or the track tension system. Any thoughts on what this might be and what to check or is it normal? The sound and feel is definitely coming from the tracks.
Just a thought. Are you working in sand? the tracks should be adjusted looser in sand as the material will pack up and over tension the tracks.
Not working in sand. The ground is mainly clay. I do have the tracks adjusted on the high end of with regard to tension.
Could be the bearings/bushings in front idler have gone south.
Running the track too tight is bad. it is better to be too loose than too tight. After running it for a while, walk around and feel the final, rollers and idler. If one has failed then it should be warm or even hot to the touch. Check the final oil. see if any metal is on the magnet. Feel the pinion area on the final case. i have seen a few pinion shaft bearings fail.
I ran a 120 or so Hitachi once that did that, got off and looked and it was one severely broken track bushing. Half the bushing was gone, and the tracks were too tight. This machine was a man's hobby machine, and he greased the trackadjuster fittings everytime he greased the machine.
I have checked the chain pins by doing the heat touch. I have not checked the front idler, rollers or final in the same way. The final oil is up to the fill plug. Where is the magnet you mention, Lee? Also, if I have the tracks too tight, might that be the cause? I used the straight edge method of putting a straight edge between the rear sprocket and the carrier roller and the carrier roller and the front idler and adding the too sag measurements together. I am a little tighter than the recommended number. I have also taken the rock guards off and cleaned the under-carriage to make sure nothing was interfering with the coils and piston that maintains track tension.
A D4 we just got this winter made a noise kinda of like that and the only thing found was that the internal wear on the pins and bushings was so bad that when you measured the distance from center to center on the pins it was 3/4 '' longer than the center to center on the valley of the sprocket so it was having to crowd alot and sometimes the tip of the sprocket tooth was hitting the bushing making the track get tight and then when you traveled a few inches it slip anyway new undercarrige fixed our noise.
When you feel the track go tight get off and see if it is tight, look to see if its got a build up of clay packed into the root of the sprocket tooth as this is usually where the build up occurs between there and the track bushing. Most materials will cause packing in the sprockets if there is enough of it, best way to clear it is to go for short run in 2nd rev as most of the material drops out on the top run of the track as it goes over the carrier rollers, avoid doing pivot turns as this drags dirt into the sprockets, and run the tracks a bit looser.I have seen recoil springs break from being run to tight in some conditions. Cheers RDG.
Good point RDG mine does what your saying awfull in snow
If the outer fill plug doesn't have a magnet on it then the inner drain does but you will loose most of the oil if you remove this plug. This is the plug that will catch any debris from the pinion shaft though so it is worth checking if you suspect a problem with the final.
Worn idler bushings, worn track chain, How is the sprocket? it too could be jumping also do not set your tracks to tight. Too tight of track tension is the number one cause of wear along with high travel speeds being second
Thanks for the responses. I set the tension down. I plan to have the undercarriage evaluated for wear ASAP.
Had a D8K with a broken recoil spring do that, the idler would retract in a turn or hard pull, always looked normal when you stop to check. Both inner and outer springs were broken