Hey guys I need some schooling on a D4H LGP series III. Owner operator stated he was pushing with dozer when it lost all hydraulics and propulsion. I am wondering if this is a pump drive issue. Does the hydraulic pump operate the hydraulics and the trans or are there separate pumps. I'm thinking that the drive gear box, if that is what Cat calls it is the problem. If any of y'all have some knowledge on this dozer please let me know what you think.
Can you remove floor plate and see if the driveshaft is turning?
Drive shaft is turning
In all gears F & R with the brakes on..?
I haven’t tried that I will do test Monday if not raining. When owner said it wouldn’t track I was thinking there was a pump problem.
Post a Serial Number up when you have one. Lots of D4H model options.
I looked for s/n yesterday but couldn’t find it. Where would it be located?
Rear left side of the frame, right under the fuel tank.
I was thinking that's where it should be but the tag is missing I'll get with the owner to get s/n
if the tag is missing the number should be stamped on the frame in the same location. Look for where the 4 rivets were that fix the plate to the frame is often a good clue as to location. It may require removal of some paint to actually see the number.
Ok thank you
I did find the serial number for this dozer:
Here’s the serial number for this machine
I’m wanting to know if there are separate pumps for hyd. and trans.
Separate. Transmission pump is a 2-scetion gear pump, the implement pump is a load-sensing piston pump. Both located under the floor and I'm reasonably sure both driven off the back of the torque converter. You can see 2 identical adapters #24, one for each pump. Transmission drive shaft comes out of covnerter on Yoke #4.] Has anyone tested if the drive shaft stops when any gear is engaged yet.? TBH it wouldn't surprise me if the shaft does not turn at all when the engine is first started, because I think that in order to fail the drive to both pumps something must have broken inside the torque converter.
I checked the drive shaft today it is turning but there is no difference in speed or direction when I changed from forward to reverse or speeds. I'm thinking that the drive gear on the torque converter has sheared and not allowing the pumps to turn. What do you think? Another question is where does the brake release pressure come from?
It’s in the 2nd section of the transmission pump. So if you want to tow it then either the brakes have to be released with a Portapower or pull the axle shafts in which case you have no brakes at all.
That's what I was thinking but it will have to wait a few days. Tropical storm came up from the gulf and expected to rain for a few days here. Will keep you updated with progress. Of course I'm sure I'll have more questions.
The drive gear on the back side of the converter is held in place by a snap ring. I wonder if that failed.?
That’s a possibility, does this housing get oil from the tranny or does it have its own oil?
It only has converter oil in it, and that's all part of the power train oil system. Here's the SysOp.