953 problem

[Matthew]

Will someone point me in the right direction to make my own post. I am new and for some reason i cant make my own post.

Thanks

 

[Matthew]

I have a 1984 cat 953. The hydrostat will randomly bog down for no reason. If i shift into neutral and back into gear it works fine again, for a few minutes, then bogs down again....
The machine isnt lacking power in any way other than when it does this... please respond

 

[NL1CAT]

Matt, after 3 posts you can start your own thread.

 

[Orchard Ex]

Matthew,
I moved your posts to a new thread so you'd get a better response.

 

[tonka]

um i would start with the basic's and go from there, air and fuel stuff...how cold is it where you are?

 

[Matthew]

Matt, after 3 posts you can start your own thread.

Thank you for the information

 

[Matthew]

Orchard Ex.. thank you for the help

Well the loader is in Lineville Alabama, and the day it happened it was about 45 degrees...

it had been running for about an hour before it started.

I bought the loader to clear some land my father and I bought together. I put about 30 hours on it before the problem started. She runs strong, I haven't found anything yet she couldnt push up with ease, and like i said other than when it bogs down it has no shortage of power.... tracks strait (doesnt pull left or right) but it will not go up a hill at all. fluid level is where the stick says it should be.

When i bought it, I ran it for an hour, but it was all on flat ground. When i got it to my place it wouldnt pull a tiny hill, but it ran strong on the flats. Then the bogging down started... Any thoughts?

 

[Per Eriksson]

Somehow I get the feeling you have an engine problem instead of a transmission problem.

I'd replace fuel filters, blow the lines from the tank and put a piece of transparent hose on the fuel return and check for air in the fuel when running.

Measuring the fuel pressure would be a good thing too.

 

[Matthew]

The thing is though, the rpms are not dropping when it happens, i mean i ll give it a shot, im open to anything, but the engine sounds the exact same when the tractor bogs down, its a hydrostat, so its running at full throtte when its on.

Its almost like two invisible hands holding the tractor in place, not letting it move and when i shift into neutral they let go, then slowly tighten their grip again as i proceed to work.

 

[Cmark]

Can you describe "bogged down" a little. You mean ground speed slows but engine rpm remains constant?

These hydrostats use charge pump flow to regulate the travel pumps, therefore correct transmission oil viscosity and a clean filter is vital. As the machine is new-to-you, I would suggest you start by draining the transmission oil and filling with the correct viscosity and replacing the transmission filter.

Search the forum for posts on cat hydrostats. Several people have been down this road before and a fair bit of advice has already been posted.

 

[Matthew]

Can you describe "bogged down" a little. You mean ground speed slows but engine rpm remains constant?

These hydrostats use charge pump flow to regulate the travel pumps, therefore correct transmission oil viscosity and a clean filter is vital. As the machine is new-to-you, I would suggest you start by draining the transmission oil and filling with the correct viscosity and replacing the transmission filter.

Search the forum for posts on cat hydrostats. Several people have been down this road before and a fair bit of advice has already been posted.

Exactly, ground speed slows (stops) and engine rpm stays the same

Ok to describe bogged down... I am operating, everything is fine for any random amount of time, be it 10 minutes or 3 hours. During a duration of about 10 seconds time the machine will go from full power to will not move, motor still running the same. Machine will not turn left or right. During this the bucket still works perfectly, and the engine rpm seems to not change. I can take the hydrostat from the current speed which i am at, reduce it to nothing with the "V" lever, wait about 3 seconds, and everything is back to normal. happens in foward and reverse.

 

[Cmark]

It sounds like the tranny is sensing a loss of charge oil flow. Because of the drop in flow, the tranny thinks the engine is being overloaded and so neutralises itsself ("vents" in Cat-speak).

Moving the FNR back to neutral "resets" the transmission.

 

[dadsdozerhd5b]

also, check the park lever adjustment as that releases the brakes. it could be that it is out of adjustment and the brakes are slowly applying. there should be a valve under the shift lever attached to the park brake. also, when you change the oil and filters, be sure to clean the pump intake screen in the suction line of the pump. it will also have a magnet, be sure to clean it also. good luck

 

[willie59]

I'm agreeing with Cmark, sounds more like a drive problem. If it were being held back back brakes, it would load the engine, he said the engine sound remains the same, just quits driving. I'm not a Cat loader tech, but I would think Cat provided a means to check charge pump pressure.

 

[Monte1255]

have you got a shop manual? if not check with Jensales.com for an oem shop manual. expensive but well worth the money. next make sure linkages are all adjusted properly. but I tend to agree with Cmark charge pressure may be the issue as it deals with the underspeed valve. The differences in oil pressure from charge pump will dump oil back to resivore and cause loader to stop just as if you had pushed the speed brake. I can scan and send you info on Charge pressure if you like as well as any other trouble shooting guides.

 

[Matthew]

Thank you everyone for your help, ill let yall know how it went when I get a day off to go and work on her( im working 7 10's) I am going to buy a the full manual here in a couple weeks-when i get some money saved back up from buying the machine.

Matthew

Union Carpenter

Cat 953
JD 450
Ford 555
JD 2440

 

[Matthew]

have you got a shop manual? if not check with Jensales.com for an oem shop manual. expensive but well worth the money. next make sure linkages are all adjusted properly. but I tend to agree with Cmark charge pressure may be the issue as it deals with the underspeed valve. The differences in oil pressure from charge pump will dump oil back to resivore and cause loader to stop just as if you had pushed the speed brake. I can scan and send you info on Charge pressure if you like as well as any other trouble shooting guides.

**************
Thank you,

I would be very grateful if you would send that information.

matthew_favors@yahoo.com

 

[maytag]

Matt,

Did you get your hydrostat problem solved? I agree with some of the other posts, sounds like you are losing charge pressure.

Tom

 

[Matthew]

Actually i haven't so much as turned the thing on since my first post. I took a job working on a new power plant for Ga power... Been putting in 70 + a week. (we just went down to 50) i am going over this weekend to change the hydro filter and drain all of the fluids and such...

 

[Master Link]

Check this out when you look at it. On the left side (as sitting in seat)of the trans on the backside of it there should be a shaft sticking out. See if you can push that shaft in and out. If you can that may be your problem as it has a roll pin in there to keep it from moving. The shaft is moving out of the correct position and drops the trans back to low speed.