The transmission temperature on my D6R has been running hot the last 1000 hours or so. On a 80-90 degree day it will get up just under the red within half an hour and then the coolant temperature will follow it. I will stop wait for 15 minutes half throttle and it will go down, but it climbs right back up. It also has more of a hesitation going forward to reverse than I think it used to. I also think it may slip the converter a little under a heavy push. The radiators were replaced recently except for the oil cooler in the center. Before I drop the converter out is there anything I should try first? The machine has 15,000 hours on it and I've only had it for the last 2,500.
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D6R torque converter going out?
- Thread starter 7060
- Start date
Nige
Senior Member
First thing is pull the screens and check for particles, then change the filter, cut it open and do the same. While you're at it pull an oil sample and have it analyzed, especially for ISO Cleanliness Code. Then post back the results.
It has a electric shift, and mechanical throttle. I thought that's how all the 6R's were and the H series was the last of the mechanical shift? Mine is a 1998 model serial number 5LN01413. I pulled the scavenge pump screen out and it was clean. Also changed the transmission filter, and sent an oil sample off. Still waiting for the oil analysis to come back right now, but the filter didn't look too bad after I cut it apart.
Nige
Senior Member
Lack of particles in the screen is always a good sign. If there was any sort of a hard failure the screen would be full of lumps of metal stuck to the magnets.
Maybe the particle count in the oil analysis will tell us something.
TC scavenge pump could be a possibility, although as you say excessive leakage inside the TC overwhelming the scavenge pump is also possible.
Depending on the oil analysis results a test of internal converter leakage might be the next step.
Maybe the particle count in the oil analysis will tell us something.
TC scavenge pump could be a possibility, although as you say excessive leakage inside the TC overwhelming the scavenge pump is also possible.
Depending on the oil analysis results a test of internal converter leakage might be the next step.
Would this be the right service manual for my machine? IDE like to buy a gauge set and do a pressure test myself. http://www.ebay.com/itm/Caterpillar...=BI_Heavy_Equipment_Parts&hash=item2ecb0bb373
Nige
Senior Member
It appears to be. Your S/N prefix is on the spine. Before you go mad bidding on ebay, check to see what your Cat dealer would sell you one for.
Hello 7060. The D6R has a priority valve system on it and I have seen them heat the torque converter when the machine stays in priority mode. The machine ECM controls the priority valve as far as when it is on or off. when it is in priority mode I believe it takes some of the oil from the torque converter system to have extra for making sure the brakes release , such as between shifts and at rpm's below 1300. You might want to make sure it is working correctly.
Thanks I'll check into the priority valve. Turns out I already had the hose and coupler to tighten the tracks on a challenger tractor. I just need to put a gauge on the hose, but does anyone know what the pressure should run on the TC? That way I can check it before my book gets here.
I believe the torque converter outlet pressure spec is 60 psi. You would have to see in what condition the machines has to be in to check it. It used to be in 3rd speed stall with brakes on but I think they may have changed that, service manual would tell. maybe someone with a service manual can look and see for sure.
I got my service manual and it says the outlet pressure should run 90psi give or take 10psi cold. With the oil cold it ran 100psi, but with the oil temp at normal operating temperature (needle straight up) it runs 75psi. The oil results came back to the dealer, and he called and said the oil that was in it was not TO-4 and to get it out immediately. I've added a couple gallon to it in the time ive had it, but I never changed it. He said the oil contained copper and metal shavings, and he mailed me the details which haven't showed up yet.
Nige
Senior Member
Have you checked your TC inlet pressure cold..? The TC Inlet Relief Valve is mounted in the priority valve, the pressure should be 130psi interestingly enough with no +/- tolerance. That's the first place to start before looking at the outlet pressure, because if your priority valve is dodgy this test will pick it up straight away.
The current specs do not list a value for TC out pressure cold, only 60+/-10psi at normal operating temperature. TC Out pressure can't be more than TC Inlet pressure, as a guess it should probably be no more than 10psi less than cold TC Inlet Pressure.
The current specs do not list a value for TC out pressure cold, only 60+/-10psi at normal operating temperature. TC Out pressure can't be more than TC Inlet pressure, as a guess it should probably be no more than 10psi less than cold TC Inlet Pressure.
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Nige
Senior Member
That ain't right ............. plus one turn of the priority valve adjustment screw allegedly changes the pressure by 20psi, so adjustment (or lack of it) would not appear to be your problem. Solenoid valve problem maybe..?
Going back to your post about the oil analysis indicating the wrong oil was in it. I'd be interested to know what criteria they used to determine that the oil was not TO-4 specification. Maybe under the circumstances do an oil & filter change as a first step and see how it goes from there..?
Here's what the valve looks like inside just to give you an idea.
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dmact
New Member
Hi, Ive had this same problem recently on a D6R, Check your brake pressure, ours was low and the small amount of extra drag raises the temp after time , same thing just let the engine bring the temp back down at high idle for a short time and you start all over again, the more you work the machine the quicker it comes up. I too went through
the other things before the brake drag fualt was found, the operator also noticed the machine starting to get a bit slugish but i couldnt notice this as not operating the machine all the time. hope this helps
the other things before the brake drag fualt was found, the operator also noticed the machine starting to get a bit slugish but i couldnt notice this as not operating the machine all the time. hope this helps
tctractors
Senior Member
dmact, thats a good point posted, the easy way to test this is as simple as knocking it out of gear on the move to see if it rolls onward without slowing or jerking to a stop, this can be an easy fix if spotted early.
tctractors
tctractors
Hello 7060. You can check your service manual on this but I believe that you should only see the 480 psi priority pressure when in priority mode, which is below 1300 rpms, and between trans. shifts, sounds like maybe you are in the priority mode all the time which can be taking oil from the torque converter circuit which can cause them to overheat, not enough oil flow. there is a pressure tap on the priority valve that does allow you to see if it working correctly. I would advise making sure that part of the priority valve is working. I think the 160 max pressure that it is talking about is when it is not in priority mode.
You are right. I just read the explanation of how it works and the priority valve is in high pressure mode when the machine is under 1300rpm, the oil temp is below 104 degrees, or between shifts. What I'm having a hard time understanding is that mine seems to be working as the specs say at 700rpm, but at 2080rpm with parking brake off it runs 480psi. When I switch the parking brake back on at 2080rpm it goes down to 150psi. Unless I understand the book wrong it wants it below 160psi with the parking brake off. It seems to be switching the solenoid when I put it in park, but it shouldn't run 480psi in neutral and park disengaged from what I understand.