D8H torque flooding

[brianscathouse]

Just bought an old D8H 46a and fixed the blown head gasket it had, filled all the fluids that were low after sitting for last 6 years and ran it for about 8 hrs and all of a sudden it started losing drive and leaking oil badly out of starter solenoid. Torque area plug on bottom was full. Drained it when first got machine and it had 2.5 gallons in there, normal I was told. After running it for 2 different half days with seemingly no issues on the 3rd day it started having issues and found the trans low and torque flooded, drained the torque, refilled trans and it emptied the amount I put in into torque in about 1 hr of low idle running while changing from a-blade to root rake. I am assuming the scavenge pump has failed but looking for other opinions. How hard is pump to change. I am waiting for service and parts manuals I just ordered and I ordered a new pump anyway. Aftermarket new was only 300 and if I am going to work of removing it I will replace it anyway. Torque heat on guage never went out of normal range and trans only had shifting issues after going low on oil. Once in gear it pushed and seemed to have no issues. On day problem occurred I was pushing stumps out of ground and loading converter pretty hard from idle to full throttle. I hope I don't have a torque problem. Pulled plug on top of trans filter and cranked over and it pushed lots of oil. Trans pump seems to work. Would torque still flood if converter bad but scavenge pump good even at low idle. I will change out scavenge pump first, but looking for advice. I am a light truck diesel mechanic and this big equipment is new to me, kind of fun though. Magnet on drain plug had small amounts of filings both times I opened it.

 

[DPete]

There should be a magnetic filter by the trans and steering pump on the RH rear of the engine ( square plate with 4 nuts on studs) pull it out and inspect. The ring of magnets is inside the outer screen. Seems like 4 gallons in the TC was OK, that might have been the K's we had though.

 

[JDOFMEMI]

Dan

It's been a while since I messed with one, as the lask 8K went away about 10 or so years ago, and the 46A about 15 years ago, but it seems like 4 gallons is way too much. I was thinking about a gallon and a half, maybe 2, but I could be wrong.

I always ran the transmission about 5 gallons over the full mark. Running in a lot of steep ground, they had a tendency to loose prime and freewheel once the tractor was too far out of level if it was not that far over. Most people told me 2 gallons over was fine, but after taking 2 rides down the side of different mountains freewheeling backwards, I would fill it to full or a little past then pour a fresh 5 gallon pail in. I quit having that problem then.

Another thing, when I had a bad pump and a flooded converter one time, it was fine sitting at idle, but whithin a couple of minutes running it would run to the hot end of the gauge and would loose pushing power and lug the engine even with no load after it was worked just a minute or 2.

 

[brianscathouse]

When I first started doing maintenance on machine it had 2.5 gallons in torque area after running it. Trans level stayed good for first 8 hrs. Is scavenge pump on bottom of torque? Does lower plate come off to access?

 

[68M]

They crack the outer aluminium housing (described as a wheel in the parts book 1t270) and fill the torque/ flywheel housing with trans oil. Often they will still work fine but the scavange pump can not keep up with the excess oil. Often if you want to check this you can pull the scavange pump out at the bottom of the convertor housing, turn the engine over and you may well see the crack. Torque convertor needs to come out if this is the case. Seen this a few times. Cheers 68M.

 

[Bob/Ont]

When I first started doing maintenance on machine it had 2.5 gallons in torque area after running it. Trans level stayed good for first 8 hrs. Is scavenge pump on bottom of torque? Does lower plate come off to access?

Brian, if you want to see if it's a bad scavenge pump, or a converter leaking too much try this.
Drain the torque, then place an empty 5gal pail inside a larger tub directly under the torque drain plug.
Start the engine and then stall the torque for one minute and shut down ASAP.
Check the oil that came out. If you have half a pail of oil it's the pump, if you have a full pail and some in the tub it's a torque leaking too much. 2 gal per min is normal leakage for a cat torque that runs in a wet housing. A flooded housing will kill the engine and make heat.
Later Bob

 

[brianscathouse]

Thanks, I will try that this weekend.

 

[OzDozer]

Brian - It's not unusual to shear a key on the scavenge pump shaft, in which case they stop pumping. The scavenge pump is easily removed from the bottom, it has a straight-cut gear that just runs on a gear on the outside of the torque divider - and once unbolted, it just drops away from the torque divider. If the pump is shot, you need to carefully check gear-to-housing clearances, and bearing-to-shaft clearances. These bearings are only cheap white-metal bearings, they nearly always need replacing.

Bob/Ont is your man, and he's outlined the Cat test for a scavenge pump that is unable to drain the torque divider housing properly.
The housing oil level must be kept low, otherwise the torque divider starts running in a big bath of oil, creating a huge amount of drag and heat buildup. This happens very quickly (15-20 mins), once you put the tractor to work.

 

[sledgehammer]

the scavange pump is easy to remove and inspect for wear.

 

[brianscathouse]

How heavy is the plate covering the bottom of the torque converter area. I won't be able to look at it until the weekend so just preparing myself. Haven't had a whole lot of experience working on big machinery. Thanks for any new info. Have manuals on order but probably won't have them till next week.

 

[OzDozer]

Everything on D8's is heavy! Make sure you have a good feed of cornflakes for breakfast before you start!

 

[brianscathouse]

Just was wondering if it was as heavy as bellypan? Doesn't look like it but it may be more of a pain as it sits above the suspension arms. I have a feeling getting it off may be a lot easier than re-installing it. Will do torque/scavenge pump test first. Just got to go to my Exxon tanker and get more trans oil.

 

[OzDozer]

I'll see if I can find the weight of the pump on the service manuals I have on fiche. Sometimes it's mentioned, sometimes it's not. They aren't that heavy, that it will require two men, they are just in an awkward position.

 

[brianscathouse]

Is the pump removeable without removing bottom center pan? It is the pan I think will be heaviest. looking through floor pan I haven't identified pump as yet and it must be on or near bottom. I am working on dirt and it has been raining last 5 days so it is actually mud. I will probably sacrifice some old plywood I have to make a work floor.

 

[OzDozer]

No, the belly pan will have to be removed. You can use a floor jack if you have some firm ground underfoot. Some guys use a chain and come-along to assist with belly pan removal.
Fasten the chain to one side of the tractor, sling it under the belly pan, and tighten it with the come-along fastened to the other side of the tractor. Undo all the bolts, then lower the come-along, thus lowering the belly pan on the chain.

I built an adaptor for my belly pans that fitted my floor jack. It comprised a square plate with four projecting pins made from bolts. Corresponding holes to match the projecting pins were oxy-cut into the belly pan.
To use it, we'd slip the rotating head off the jack and replace it with the adaptor. Slide the jack under the tractor, locate the pins in the holes, then jack it up until some light pressure was applied (don't apply too much pressure, this will make the belly pan bolts hard to unscrew).

Once the belly pan bolts are all out, lower the jack and roll it out with the belly pan attached. Some tractors, you need to drive the tractor up onto pieces of timber to get enough clearance.
We always tried to get the tractor back to our shop where we had a concrete floor, if belly pans had to come off. Field removal of belly pans ain't fun. It always pays to drop the pans regularly to keep the dirt level down, this makes handling them a lot easier.

 

[brianscathouse]

That is what I thought and I thank you for confirming, hate to remove more than I have to. I want to fix and put it back to work so I can get some earth shaping done before winter hits us for real. I only have weekends to do that. Over winter I may move machine to a friends shop which is setup to work on this type of machinery and go through it with him (young HD Tech) and maybe make it a production machine again. For now I just need to get about 10-20 hrs more work and clean up my property before winter hides my mess. I usually get 2-3 feet of snow that lasts from December till March.

 

[brianscathouse]

So did the test that Bob/ont said to do by running machine with a bucket under torque drain for 1 minute and only got 2 gallons oil. Removed scavenge pump and disassembled and all looks perfect. Pump is fairly new already. Not a mark on gears or housings. Also removed inlet screen from bottom and apart from a few metal shavings trapped on outside it isnt restricting flow. Any other ideas. I see pump has 2 rotor sets . Is it dual function pump? I dont have a manual yet so was wondering what other possibilities there are causing the flooding.

 

[Bob/Ont]

If you stalled the torque doing the test your torque is sound Brian. Make sure the hoses from the pump sections are going to the right place. One section is scavenge aand it goes to the lube valve, forget were the recirculating pump is hooked up.
Later Bob

 

[brianscathouse]

Confirm torque stalling. I started tractor in gear and was at about 1/2throttle with brakes on. Coupler shaft was still turning though. Maybe I need to retest. Pump was accessible through a small plate removed from bellypan. Hoses were the biggest pain . But they had to be routed properly or it wouldnt have worked in first place.

 

[OzDozer]

If your coupler shaft is still turning when you have it in gear and the brakes locked, and the tractor not moving - then your transmission clutch plates are slipping.
This can be due to badly worn plates or inadequate oil pressure to keep them fully engaged.
If you only got 2 gallons from the housing, then you haven't got a torque converter flooding problem any more.
I'm at a loss to understand how you indicated torque converter flooding initially, but draining the housing doesn't back that up.