Cat 953 travel problem

[John5450]

Hello new member here. I have an early 80s 953 78y01021 intermittent left side tracking problem. Bare with me as this is hard for me to explain, the left track doesn't engage at all times but sometimes will and it's fine until you stop again forward or reverse. We did a test so to speak when it started pulling I pushed into a large brush pile both tracks spun with plenty of power. I have a friend who is going to come out soon to check pressures and other things just want to gain a little insight for trouble shooting

 

[CM1995]

Welcome to the Forums John.

I see you've already added the pertinent information for our mechanical members - serial number. Unfortunately I am of no help as my forte' is on the construction end of equipment and not wrenching.

We are fortunate to have a lot of knowledgable members here on HEF so be patient they'll be around when they see the thread.

 

[John5450]

I would like to add that I have already changed fluid and filter and checked all steering linkage including heim joints under trans cover.

 

[Tyler d4c]

The left pedal isnt sticking down is it. Assuming you checked it already

 

[John5450]

Left pedal is not sticking

 

[Cmark]

OK so here's a question.
If you're driving along at full speed and then slam it into neutral, does it stop in a straight line or does one track stop before the other and make it pull to one side?

 

[John5450]

No it stops even unless the one side isn't pulling it will idle under the power of the other track and didn't quite go straight

 

[Cmark]

With respect, I don't understand your answer. Can you rephrase it?

 

[Vetech63]

No it stops even unless the one side isn't pulling it will idle under the power of the other track and didn't quite go straight

I am reading your answer as the machine stops evenly under Cmark's guidelines....?

 

[John5450]

Yes it stops evenly as long as both tracks are pulling. When the problem occurs and the left track doesn't pull it will free spin/idle under the power of the right track

 

[Cmark]

Okay, let me clarify the question.
You're on a nice flat, solid, level piece of ground. You're barrelling along at top speed, nothing in the bucket and no real load on the drive train. You slam the FNR into neutral. Does it stop in a straight line?

I'm off to bed now. Future replies may be delayed.

 

[Bill Edwards]

Can't help on the problem but it sounds like when the machine is working correctly it pulls up straight.
When it is doing it's fault it doesn't stop straight - but this problem is intermittent.

 

[John5450]

Yes bill that is correct

 

[John5450]

Still trying to figure this out. Had someone come out and check pressures. He stated that transmission was fine suggested it to be something in the final drive, I have removed the final and since taken it to be rebuilt to Wich the shop tore it down inspected and says nothing wrong with it I had them put new seals. Now I am leaning towards the drive motor. If I don't figure it out soon I'm gonna go crazy.

 

[Cmark]

This is a cross section of the left hand charge shuttle valve (Part of the replenishing valve assembly). It lives on the front of the transmission along with an (almost) identical one on the right. I suspect you may have seals #10 and 11 blown. If you're replacing them, it's worthwhile doing the other side at the same time.
Do you have a shop manual or a parts book? If you can't identify where they are, I'll try and find some pictures.

 

[Nige]

The valve CM is referring is #46. The corresponding one on the RH side is #16.

 

[John5450]

There was only one piston under the cover in the #46 location are you sure that's the charge shuttle valve. Parts Diagram didn't match up to what we were looking at

 

[John5450]

 

[Cmark]

Referring to the drawing in post 15 above, what you have in your hand is piston #15. You need to remove block #18, then you will see the end of seat #12. From memory it has a couple of tapped holes in the end to help pull it out.

 

[John5450]

So that's not block#18 in the picture that the piston sits in