Hi All, Got a problem with a D6c 47j272 power shift non turbo. after 4-5 hours work on a warm day +20 degrees c the converter will run in to the red. There is plenty of power in the tractor and the converter seems to do its job fine. it overheats even if it is on a easy dig !! using my 9/11 onions box. It has developed a noise in the trans pump however I have checked the pressures at the steering clutches and directional clutches and the pressures are down by about 40 psi but not affecting the machine control at all. I have recently replaced the bearings on the bevel gear shaft and replaced all the seals in the clutch pistons on the back end and wondered if this was causing the heat, It seams not. With my small understanding of torque converters I am surprised that it takes 4 hours of work to get hot? I have also cleaned the magnetic filter and found some metal however this could have been from the bevel gear flange plates as they were very badly warn. please help help help I have run out of ideas. regards Jason
Torque converter housing not scavenging properly would be my first guess. Changing tack a bit. How clean is the radiator and what is the condition of the fan belts/tensioner mechanism..? I'm not saying that's your problem, just want to rule it out as a possibility.
Hi nige, Converter scavenging ok I dropped the oil when hot and got about 10 liters also engine not running hot at all in fact it is very cool needle only just makes it to the green after a hard days pulling also I have removed the oil cooler and cleaned Thanks Jason
Most commonly when the torque starts to overheat it is because there is too much clearance between the housings. Having said that there should have been aluminum in the screen. Have you cut a transmission filter yet?
Classic symptoms of excess torque converter leakage and over loading the scavange pump. Would be furthur aggrevated ( as indicated by transmission pump noise) if there are issues such as restriction or sucking in air.
hi I did find metal in the magnet filter but that has prob come from the bevel gear flange plates however I have cleaned it now and will run for a few days and see if more metal builds up. how long will the torque run like that ? and will it do any permanent damage if I keep using it but keep an eye on the temp? also is there any thing I can do to keep it cooler wile I finish the job I am on ? maybe rain the throttle back a bit? thanks
As OM says it all sounds like the classic signs of excessive internal converter leakage or a sub-par scavenge system. The scavenge system is fairly simple to check, look at every gasket and O-Ring in the suction side of the scavenge pump. Even the pump itself is not rocket science to tear apart and inspect for wear or seals that have gone hard. The aluminium produced by internal converter wear won't get trapped in the magnetic screen (too small & it's not magnetic anyway) - it will find its way into the filter. The only way to find it would be cut a filter apart and look right in the bottom of the pleats. Your 10 litres of oil from the housing is not necessarily representative IMO. Think of it like this, the machine is working and the internal leakage is higher than the scavenge pump's capacity - the converter heats up. As soon as you shift to neutral the internal leakage rate drops like a stone and the scavenge pump "catches up". You stop the machine, look in the converter housing and find 10 litres but that's not necesarily representative of what's in the housing when the tractor is pushing hard.
thanks nige, I will check the seals as there is leakage from all around the torque converter from the pump and the relief valve. the problem is its an old machine and every seal I find is flat or brittle!!!!! one other thing is now you have said that the machine didn't overheat when on a short haul maybe because its spending more time in natural ? when its on an easy dig on a long haul it gets hot ? I only used in first for the morning and it got hot and then used second as well in the afternoon and it got hot to, my thinking was the speed clutches heating the oil. but will try a shorter haul on wed and report back. j
Having just resealed the steering clutchs and created a prolem sounds like the steering clutch valve spools are leaking through and causing the drop in preshure and a partial release of the steering clutches. Put a gague in one of the clutch ports and run tractor and look for residual preshure. Could also be improperly adjusted linkage.
JD, most converter over heating is lack of oil flow through it and out to the cooler. Check the pump pressure with warm oil at full throttle and at idle. Pressure should hold about 90% of full throttle value at low idle. If there is a big pressure drop look under the trans cover first at the RH rear corner for blown seals on the feed tube to the trans valve. Come on back with what you find. Later Bob
Also check transmission lube oil pressure, it's the last thing to receive oil and should not be less than 9 +/- 3 psi.
Thanks bob I am away for a few days I will check on mon. Where is the best place to check pump pressure as I have no test port on the trans filter housing ? Also if I take the trans cover off should I start the machine to look for leakage ? Should there be any ? Thanks jd
There will be a lot of oil coming out of the valve gently and a big squirt any time you shift so stand back while shifting. What I want you to look for is a heavy flow of leakage around a small tube( 1" dia) coming in from the back. It carries oil from the pump and tees off from the oil going to the steering valve. There are yellow orings that blow out, lose pump flow and cause overheating. Check pump pressure at 1/8" pipe plug on top of valve, marked P1. Later Bob
trans pump has unraveled, putting the junk in the mag screen.
Hi Bob, Sorry for the delay I have been away. Right I have striped the trans pump and found the bearings are warn I have replaced them I have also run with the trans cover off and found no oil leaking around the pipe in the bottom right hand corner only oil coming from the valve block when shifting (thanks for the warning I did stand back !!) any more ideas. is it worth cutting the trans filter to look for aluminium ? cheers jason
Yes always good to check screens and filters first. Then check the pump pressure at high and low idle with warm oil. If there is no plug on the filter housing there should be a couple on the big valve body on the converter housing. They will be 9/16 NF stor boss, this body holds the main relief and converter inlet relief valves. This valve has a hose from the pump and one back to the rear corner of the trans. One plug is pump pressure the other is torque inlet(100+psi converter stalled at initial startup with cold oil) Pump pressure should be 300 to 350psi this can be adjusted the important thing is pressure drop from high to low idle(20% is okay but I like to see 10%). Come back with what you find. Later Bob
We have a D6C (10Kxxxx) with the same problem with the torque running hot after a couple hours of hard work in warm weather. I looked & am not sure where to find the screen or screens? Can you tell me where it is located? Just did a service before the overheat problem occurred so we just tossed the trans filter. Saw a flap door on the floor (near the decel pedal) about 2" x 5" thinking it may be there, but under the cover was a bolt on cover with some adjustments under there. What are the adjustments for? Other than the overheat problem in hot weather it seems to be a good running machine, only having owned it for about 9 months.
Follow the trans pump suction line back and look for a housing with a 4" square cover held on by 4 nuts. The magnetic screen is under it. Later Bob
Don't know what the addjustments are. Later Bob
Will this be located back near the bevel gear compartment, under the seat somewhere?
Is under the floor panel next to the brake pedals right side i think ,been a while since i have had the D6C.
Also another screen in the convertor,take off small plate in the belly pan to get to it.Willd loss a little oil,but not much unless convertor has issues.
its on the left just behind the left break pedal you can get it out with only removing the small floor plate between the break pedals as the bigger floor plate is a pain to remove. I found as it is a magnet the best way to clean it is to pressure wash on high heat and then rinse with petrol.
hi there they are not adjustments you talking about the cover on the transmission they are pressure test ports one is for direction clutch the other is for speed clutches.
Hi Bob, Not working the machine again the weather has turned in the uk storms Monday I hear !!!! I will test the pressures when the machine is working again thanks.
This is the cover that I was referring too. It is just back from the decal petal. Any idea what is under the bolt on cover plate?
The speed and directional clutch pressure taps are under the plate. Later Bob