We purchased a d8t SN CAT00D8TEKPZ02545 in an auction sight unseen. It shifts well, pushes hard and doesn't run hot. It came back and the tranny lines appear 'crispy' so it must have been hot at some point. We've pulled some black plastic out of the transmission scavenge intake. The plastic appears to have been forced through something tight because it's long, thin, and brittle. Any idea what's come apart to melt that black plastic? Is there anything that would melt black plastic in the steering somehow? Nige suggested it might be clutch piston seal turned black. Any other thoughts? I appreciate this!
I wonder if this is something off the filter element??? tctractors
Another thought is that it might be the remains of one or more planetary gear thrust washers if that tranny uses plastic washers instead of bronze ones. I’ll have to take a look at some Part Numbers.
It has been many years since I have been inside of a dozer transmission. But I recall one of the clutch packs having a black bonded type rubber friction disks. I would perform a stall test on all speeds forward and reverse, and check pressures. Could be nothing but contamination. But at least you can know the health of your transmission based on the stall test and pressure readings.
Blowing it up looks like some of it is a definite shape, possibly end seals from a filter??? Wonder if the filter is a genuine Cat or aftermarket. Could be the tranny got hot and the operator wasn't paying enough attention or decided to move the machine instead of letting it cool off and that caused the filter to start coming apart.
Confirmed that the planetary gear thrust discs (36 total in the assembly) are plastic. It might pay to have a transmission oil sample analysis performed if you haven't done one recently.
Thanks for everyone's feedback so far! Tranny oil was sampled, please have a look. Nothing too alarming at first glance. For filters we run the 328-3655 from Cat. They do have black molded ends which could have got soft. My mechanic thinks this black plastic was pressed through something at high pressure, not necessarily melted. The plastic strips are rounded and almost have growth rings like a tree... We'll add new oil and run the stall test pressures.
Nothing frightening in that analysis as far as I can see although I doubt very much that the oil had 3000 operating hours on it and still had an ISO 23/18/12 Cleanliness Rating.
It had less than 400 hours on it. It's a dozer that we seldom use.
According to the SOS report the oil had 3000 hours on it. Someone didn't fill the sample label out correctly.
The hard thrust disc's on the gear carrier usually crack up and found in little sections that still look like the component, i cannot think of anything else within the transmission that is remotely like the parts found, in the diff steer and brake units there is plastic thrust washers but I think they are Brown? or gold? the filter is still a good possibility, was the torque case drained and checked for bits, if the washer was out of the gear carrier metal sparkle would be building up fast, if the washers in the diff steer units are black it would be from the R/H side, the easy side to pull off. tctractors
Thanks guys, I appreciate your help so far. The pressures were checked and deemed to be within the Finning specified ranges. The dozer went back into service and the operators are complaining that it periodically jumps itself into PARK when they are pushing. Does this symptom trigger any other ideas?
park brake or brake pedal switches is the first thing that comes to mind. Should be able to access Diagnostic Codes from the monitor. Do the operators know how to do that.?
Not likely. I know I don't know how...
See attached. See if you can find a list of Active and Logged Diagnostic Codes and report back.
Here's what the field came back with
Both transmission output speed sensors - that'll do it. See attached, but to do the troubleshooting either one will need to be active. My suspicion with both sensors going out at the same time is there will be a fault in a harness connection somewhere, maybe even in the jumper harness located inside the transmission.
Thanks! I'm on vacation but I've passed this to our tech who will head to site and check on these.
The problem is that unless the Codes happen to be active when he tries to troubleshoot them, nothing will show up as a result of all the tests and everything will look kosher.