D6N Codes — Dozers

It might be a stupid question but are you absolutely sure there is oil visible on the transmission dipstick.?

Nige said: Here’s what I suggest.

1. Connect a 50psi gauge to the port I marked above. Start the engine and let it idle. If you have absolutely zero pressure on that gauge go to the next step. If you have any pressure at all, revert back here for further suggestions.
2. If there is absolutely zero pressure then remove the quick coupler from the same test point and start the engine at idle. Do you get any oil at all out of it.? It goes without saying that you need to do this step VERY CAREFULLY. Oil under pressure could seriously injure somebody. Click to expand... All I had was a 250psi gauge and I had nothing. This is what the back of my dozer looks like. I took a pick and mashed the port in. No oil at all ran out.

Nige said: Here’s what I suggest.

1. Connect a 50psi gauge to the port I marked above. Start the engine and let it idle. If you have absolutely zero pressure on that gauge go to the next step. If you have any pressure at all, revert back here for further suggestions.
2. If there is absolutely zero pressure then remove the quick coupler from the same test point and start the engine at idle. Do you get any oil at all out of it.? It goes without saying that you need to do this step VERY CAREFULLY. Oil under pressure could seriously injure somebody. Click to expand... Removing that fitting reminds me how we use to bleed the pumps on underground machines on start up or it they ran out of oil. We use to put 2 psi with a rag over the fill hole to help push the oil to the pump. It is either air locked or something is very wrong inside. In post #16 it was said to remove suction screen from bottom, was it ever done or did I miss something? Simon C

Simon C said: Removing that fitting reminds me how we use to bleed the pumps on underground machines on start up or it they ran out of oil. We use to put 2 psi with a rag over the fill hole to help push the oil to the pump. It is either air locked or something is very wrong inside. In post #16 it was said to remove suction screen from bottom, was it ever done or did I miss something? Simon C Click to expand... No I did not. Until now I believed the issue was electrical. But now that I’m tearing deeper in it. I’m gonna pull it out.

paulstrozier84 said: No I did not. Until now I believed the issue was electrical. But now that I’m tearing deeper in it. I’m gonna pull it out. Click to expand... I think removing the screen is probably the next logical move. As mentioned earlier it will require the bottom guard under the transmission/torque converter removed (and the powertrain oil drained) in order to access it - HOWEVER...........

1. Did you confirm 100% certain that there is oil in the transmission.?
2. I would still suggest that you remove the test point completely and at least bump the engine over on the starter to conclusively prove there is no oil flow whatsoever at that point. If that is indeed the case, read on........ The fact that there is no oil flow at the pump pressure test point indicates (to me at least) that it is a problem upstream (pump side) as opposed to a problem downstream (brake/transmission side). This is because if it was a problem with the priority valve causing a loss of oil to the transmission there would still be oil pressure at that test point but it would be going to the brake system. To me it boils down now to two possibilities.
3. No oil is reaching the pump - could be a plugged suction screen or a collapsed pump suction line but if that is the case why are there no cavitation noises coming from the pump.? At least there has been no mention up to now of such noises.
4. For some reason the transmission pump is not turning or has suffered an internal hernia. that's going to need the pump removed to diagnose why.

Yes I know it’s full of oil. And there is no noises. It is quiet as a mouse. I’m getting it ready to pull the screen now so I’ll update when I can

paulstrozier84 said: I’m getting it ready to pull the screen now so I’ll update when I can Click to expand... If you haven't removed the bottom guards already see the attached. Budget on everything being at least 50% heavier than stated, simply because of the amount of dirt that will be in them.

paulstrozier84 said: This is what the back of my dozer looks like. Click to expand... Looking at that photo is there another test point hidden behind the blue hose & wiring.? I thought that I could see the edge of a rubber cover in the shot. If it is actually a test point then that’s the one you need to be on.

Nige said: Looking at that photo is there another test point hidden behind the blue hose & wiring.? I thought that I could see the edge of a rubber cover in the shot. If it is actually a test point then that’s the one you need to be on. Click to expand... That’s the one I used. And it’s got nothing. Screen is out. I mean it’s got some but nothing like a major failure I believe.

paulstrozier84 said: Screen is out. I mean it’s got some but nothing like a major failure I believe. Click to expand... If you have never previously removed that screen during the time you have owned the tractor then what’s there and on the magnets is just normal wear. Time to pull the pump I think.

It is the first time it’s been out for me but I’m gonna assume the pump is the one with the suction hose to the transmission?

I do believe I have found the issue. No idea how the operator never heard this but oh well. Will hopefully update once parts arrive to repair this.

Is that the drive shaft for the transmission pump.? If it is I just won a $20 bet......!!!

Yes sir it sure is

paulstrozier84 said: I do believe I have found the issue. No idea how the operator never heard this but oh well. Will hopefully update once parts arrive to repair this. Click to expand... Think you were correct about your hunch Nige earlier this morning.. That why I like to follow the tutorial. Simon C

Simon C said: Think you were correct about your hunch Nige earlier this morning.. That why I like to follow the tutorial. Simon C Click to expand... Like always, follow the data.