D6h tc issues

[D6hmatt]

Good day gentleman. I have a issue im trying to iron out with d6h dozer ser 9kj00922. I was pushing away all was good no signs of heat on tc or anything and boom loss of power and leaking powertrain oil. I shut down and looked more into things and im leaking out of tc breather and im also pushinng powertrain oil into engine. I pulled stump pan drained tc it had like 10 galloms of oil come out so it appears flooded. check scavenge screen it was clean. Im curious where to go from here how to test my scavenge pump out and eleiminate it being a tc issue or a pump. Cats run good ive have it for 700hrs or so it has 5800hrs on it. pushes good never seen any temps higher then 110c on tc this just came outa no where. Im just curious also where oil can get into engine through starter ? Or rear engine seal? Say if it is a dead scavenge pump will guy probable have to pull tc also to do rear engine seal? Just looking for some advice.

 

[nicky 68a]

Not too well up them,but doubtful it would be a rear crank seal.
Scavenge pump most likely as you think or tc needs resealing etc.

 

[Nige]

I'd suggest first step to get the transmission pump out and have a bit of a sticky beak inside it.
If it checks out I think you are looking at excessive leakage inside the converter.

 

[John C.]

My first thought is something wrong with the drive gear for the scavenge pump. Next thought would be crack in the turbine housing of the torque converter. I believe you are going to have to remove the torque anyway if you are pushing trans oil into the engine. Have you ever had the transmission out of the machine for overhaul? An H model is an old machine. Keep your eyes open as you dig into it.

 

[Nige]

My first thought is something wrong with the drive gear for the scavenge pump.

That was my first thought John, but the scavenge section of the transmission pump is the one closest to the converter. So if there was an issue with the pump drive there would be no transmission pressure either. This appears not to be the case.

 

[Nige]

That was my first thought John, but the scavenge section of the transmission pump is the one closest to the converter. So if there was an issue with the pump drive there would be no transmission pressure either. This appears not to be the case.

That is unless this illustration is incorrect.......

 

[D6hmatt]

Ok makes sense. I plan on pullimg off scavenge pump assemble next and getting it looked at. I got it loaded and hauled home barely but now atleast im close to my shop. I fooled around with it a bit yesterday i drained tc it had 12 galloms in it. So for kiks i fired it up just at a idel to see home much oil comes out and it appears quit a bit like filled a 5g pail in less then a minute, i put my hand on scavenge pump hose to see if has suction and it does but i mean thats not a real good test either a worn out pump im sure still makes a little suction against my hand so i will pull that pump doesnt look like a huge job. But my question now is how much oil gets pumped into tc at a idle not in gear like could i be flooding it from a cooler return line return or feed line regulator stuck open or something and my scavenge cant keep up? It sure seems like alota oil pumping through that tc housing at any given time. Or if that tc itself has a big crack or damage would it pump oil like crazy into housing? Thx. Matt.

 

[Nige]

The recommended way of testing the internal leakage of a torque converter is to first get the machine up to operating temperature then stop the engine and drain the converter case. Dump the oil back into the transmission and put the bucket back under the converter drain port. Start the engine and immediately stall the converter against the brakes with the transmission in 3rd speed forward. If the bucket is say 5 gallons then time how long it takes to dump around 3 gallons or so of oil into it. Come back with your results. I fear you will be dumping 3 gallons in just a few seconds, which is not good.

 

[D6hmatt]

Ya exactly it. I cant even warm
The machine up to test tc. If my tc is that bad of shape shouldnt i have seen a warning somewhere along the line? Just minutes before i first started leaking and flooding that cat woulda climbed a tree if the bark woulda stayed on like run excellent push like crazy and run cool ive never realy had any issues but it is older and i have no records on whats been done to it. Unless it is just a weak scavenge that finaly gave up the ghost and thats just it. Im curious though why i get so much oil at idle in the tc case or is that normal?

 

[Nige]

I’m in the same camp as John C. I think there’s a good possibility that your converter has suffered an internal failure such as a cracked housing.

 

[D6hmatt]

Ya exactly it. I cant even warm
The machine up to test tc. If my tc is that bad of shape shouldnt i have seen a warning somewhere along the line? Just minutes before i first started leaking and flooding that cat woulda climbed a tree if the bark woulda stayed on like run excellent push like crazy and run cool ive never realy had any issues but it is older and i have no records on whats been done to it. Unless it is just a weak scavenge that finaly gave up the ghost and thats just it. Im curious though why i get so much oil at idle in the tc case or is that normal?

 

[Nige]

If it’s a crack in a housing that is dumping all the oil it could have opened up in a split second. That would explain it. However that still doesn’t remove the necessity to ensure that the scavenge pump is working correctly first.

 

[D6hmatt]

Makes sense. Ya i will get pump pulled off and go from there make sure its working correctly. Is the tc sprayed in oil all the time for cooling i assume? Like at any given time there will be oil flowing through tc housing being scavenged out even in neutral?

 

[Nige]

Is the tc sprayed in oil all the time for cooling i assume? Like at any given time there will be oil flowing through tc housing being scavenged out even in neutral?

There will be internal leakage in the converter all the time the engine is running. How much leakage will depend on how much load is on the converter.

 

[D6hmatt]

Ok makes sense. Im hoping to get pump pulled off this week and checked to atleast eliminate the cheepest option first.

 

[John C.]

The leakage in properly working D6H converter with be next to nothing. A failing pump will do it gradually. You still have oil transfer into the engine. Your description of a sudden problem indicates a seal or part failure. Pulling and tearing down the transmission pump is a reasonable next step but make sure the owner of the machine doesn't get their hopes up. Prime the pump with a conversation about the high percentage that the convertor will have to come out for repair.

 

[D6hmatt]

Well i am the owner hahah hopes were lost the day i bought yellow equipment hahah. so no suprises here im just tryimg all the easy and cheep stuff first. I poped off the pump and looked it seems like a used pump nothing spectacular worn. So like you say things looking more like a tc issue. Is there a direct tc pressure one can check to realy narrow it down? I would assume as much loss of oil im having the press would be alot lower out of spec.

 

[Nige]

See the attached for powertrain test & adjust.

Converter inlet pressure should be no more than 100psi with cold oil.
Converter outlet pressure should be 60+/-10psi with hot at operating temperature and stalled against the brakes in 3rd speed forward.

 

[D6hmatt]

Ok sure thing i will give that a try when i get a chance. Thx

 

[D6hmatt]

So i got this tc over to mechanic and we split it appart. Looks like a bearing started to fail and took out seals cause a bit of damage. So we will rebuild and carry on. What in some of ur guys opinions is "hard on" torque converters like what work is detrimental to them.