Hey guys, I have a Cat D5H Series 2 LGP, will not move, tracks are free I know because we have pushed and pulled it with the sprocket shafts pulled, I checked the transmission pump pressure got 15psi at idle, and almost 100psi at full throttle. What is this pressure supposed to be? Also could the filter screen be plugged and do I need to drop the belly pan to take the screen out to clean it? Could anybody help out? Thanks
Should be somewhere around 350psi High Idle with the oil at normal temp and the transmission stalled against the brakes in 3rd speed. A Serial Number gets more accurate information. The suction screen should be inspected and yes you will have to remove a bottom guard to access it. More of the background story about what happened before the tractor stopped moving altogether might also help.
Not sure if the 5 is the same as the 4 but on the 4 there is a filter under the floor pan.
maybe broken tube in rear housing
Thank you guys! Nige, as far as the background on the tractor, the previous owner said it started slowing down gradually over an x amount of time until finally wouldn't pull itself, we were thinking there might not be enough pressure to release the brakes, which obviously is the problem, could that have caused the brake bands to weld to the drums, or whatever is in there? I have no idea what is in there as I don't have a service manual.
eBay is the best source I have found for used equipment manuals.
Not necessarily because a lot of eBay sellers are exptremely proud of their used manuals, often pricing them at more than a new one. Apart from that, to identify the appropriate manual needs a machine Serial Number as a starting point.
There are no brake bands. The brakes are multiple disc type, spring applied and released by oil pressure. Why not start with a few basics.? 1. Look at the transmission oil. Does it appear to be clear and bright or dark and cloudy.? Does it smell burned.? 2. Remove the suction screen/magnet assembly and inspect for particles. Take photos of what you find. 3. Remove the transmission filter and cut it open. Inspect the filter media for particles. See this VIDEO . Yes I know it's an engine oil filter but the principle is the same.
I agree on needing the serial number to obtain the correct manual. Once in hand I have had great luck finding a good used paper manual(s) on eBay. I will say you need to be diligent with the ones that claim to be complete. Most reputable sellers will show a picture of the contents page and corroborate that with photos of each section. As always with anything used, do your homework.
Just got done draining over 30 gallons of transmission oil, checked the suction screen all clear, oil smells good, clear bright oil, should I go with pittsburgh cat man, broken tube? or transmission pump? any other suggestions???
With as big of pressure drop as you have it sure sounds like a large leak one question I have when you say near a hundred pound at high idle could it be possible it's around 85 psi witch is primary pressure
It might be worth a shot to pull cover at top rear of transmission and see if the load piston plug is still in the pressure control valve
When it's cold it runs just over 100psi, but when it warms up a bit, it won't quite reach 100. It may come down to 85. I don't think so but not sure
What pressure of gauge were you using as too high could be out significantly. Simon C
Like 250psi
That gauge would be good range. Just asking as we are not there. Simon C
What does the load piston plug look like? I'm new to this dozer, sorry
I finally found the serial number 1DD00356 What year is it?
About 1986 I'm sure someone can tell you exact date
1986, but remember that all parts and service information is based on the machine Serial Number not the year.
I need a diagram of the whole transmission, tubes, control valve, all of it. Time to get this thing up and running!
One question I have, I took the pressure reading from the plug/port on top of the filter housing, is that where I should have 350psi?
Hum... we have one of those... we had almost same problems except ours would still move for an hour or two... before stoping. What is happening is your system is not pressurizing enough to release brakes, but that does not matter much as from a certain below pressure the TXM does not engage. If I was in your shoes i would remove the TXM pump and inspect it, certainly it is toasted as those are replacement items every 4K hours i read somewhere. "If pump looks good" next step is to check leaks on brake clutches seals. (that tractor system does not release brakes unless the main charge pump has a press of around 15/20 BAR, and if thats the case the priority valve does not open pressure to TXM control bank, as this valve is rated to operate around 29 bar full open (thats why it might open around 23 , 24... and alow TXM operation) If everithing is still good here , and no reason not to, next step is check TXM cluch seal leakage. And at last piping inside TXM case. (or at first is up to u) There are a number of ways to check this pressures on the tractor, manual tell u to check P1 or P2, does not help much, There is also brake and steering clutch pressure taps, i do not consider them helpfull in this case as one can´t find leaks by taping those pressures. Be aware that this is a modular machine, reseal brakes and steering clutch can be done in less than 2H for less than 500USD, when u have the modules of the tracktor, TXM might take u 4H and 1000USD. TXM charge pump from china 1.5K This machine also have a Torque converter , there might be problems here too... but thats secondary... good luck
See attached. The illustrations are not the greatest. For some reason the RH side got chopped off some of them. You really need a Parts Manual. Search for Caterpillar Publication reference SEBP1557. You can get one from either HERE or HERE . The first link has the option of a download that you can have within 5 minutes or less of paying for it. Both have options of pdf files on a CD or paper copies.
See the attached testing & adjusting procedure for the location of pressure taps and the specifications for them.
Thank you for your help!
So we got the transmission pump off, we gonna check it out and put it back together, anything I need to know before I dive into it?
For the pump... nothing special to it, its gear pump with 3 chambers. Chamber A, TC oil feed and prime of Chamber B, Chamber B is what matters Chamber C, TC scavenge, wile at it inspect TC scavenge strainer, that rules out TC damage. In case u have doubts about inspection, post pictures BTW ascertain if CAT pump still in it or already a AFM replacement? regards
Thank You