Recently bought D8H 46A dozer thought I got a good deal until I had to put 20 gal of hyd oil in transmission. Where did all the oil go I wandered until I ran it in transit for an hour or so. Issues: It took about a minute or so before driveline would turn at proper speed when under a load. Still does at startup. More alarming was when I noticed starter was covered in (old and new) oil and oil was dripping out the bottom at a fast pace. I did a stall test and the engine did significantly pull down but not close to engine stall. Stall test RPM was the same in all gears forward and reverse. Left brake has excessive travel hoping that is adjustment issue, haven't tackled this yet. I am thinking torque converter has to come out! What else could it be other than the input seal. What kind of RPM draw down would indicate week TC. Any thoughts on how I should proceed?
Your torque is flooding. It could be because of pump failure or rings worn out not really much to them check pump first if it's ok torque will have to come out
Hmmm where in Wa? Hydraulic only goes in the hydraulic tank for the blade and ripper if it has one. series 3 SAE 30 goes in everything else. Maybe thicker if in a hot climate. Good deal? Under 10K? Yeah old dozers are pretty worn now as compared to 20 plus years ago.
Thanks for responding to my D8 issues. I assume Cat Man is referring to the scavenge pump. Does the test consist of running it for a while then draining the TC to see if it has more than 5 gallons? Would this explain why it take so long for TC to come up to snuff or is that normal and what kind of RPM drop should I be getting with stall at full throttle? What rings are you referring to? We farm in Eastern WA. Thanks.
I'm thinking stall should be Torque converter stall speed is 1056 rpm If you get 5 gallon it's flooding. you should only get a gallon or so. also if its flooded it will make heat
I know this is a d9 but the torques are the same except the 1 t 270 wheel is replaced with a 1t633 on a d8 the rings that go bad are a 1t309 usually the 1t256 gear is worn bad as is the 1t231
I plan to have a go at this in a week or two. If there is something internal wrong with the TC I might be better off getting a reconditioned one they are advertised for $4K or so. If however digging into the internals isn't rocket science I might give it a try. It doesn't look like it is too hard to take in out, just big and heavy and probably very messy. Will need plenty of floordry. Are the sealing rings buried deep in the bowels of the thing? Your thoughts.
The torque disassembly and assembly isn't rocket science no special tools required. I was thinking I think I would pull the starter and make sure it had a gasket where it bolts to flywheel housing also make sure their is little rubber balls in the blank holes on the nose piece then check how much oil you get out of torque
Sounds good I will give that a try, thanks
What about pressure tests? Driveline turn proper speed? Was the machine moving? Does the drive line turn when doing the stall test?
The torque has a few snags to strip it down, you will need a lock set to hold the housing solid while you undo the big fancy fastener, it might be loose if you are lucky but will need tightening up to a high ft lb setting, so you will need a fancy lug drive socket to tackle the job and a way of holding the drive case to reach this target, I have 2 divider gears welded to a big chunk of solid bar, you might be making small a job a lot of good mechanic's mess up, the drive divider will also need work plus the 2 torque bearings will need replacing plus the 2 drive shaft bushings that can be fitted 2 ways with only 1 being correct, so any dummy can do this repair with a set of pipe grips and a hammer, the scavenge pump is best removed on a D8H/K to save damage, it has to be removed on D6C/D and D7E/G , don't forget to strap the drive in place when you pull the case, the same gasket fits the powershift or direct drive case, it is an easy job if you have the correct tools and know exactly what you are doing, otherwise it will be entertaining and a long weekend, wishing you the best of luck with the project, some place in that CAT sprocket pulling thread of mine in Shop Talk is a few D8 Torque's be worked on.
That Big Nut might be a problem as it needs an internal peg drive socket.
I haven't done any pressure tests yet. Any recommendations where to proceed and which tests are applicable. The machine does move once the TC come up to snuff by teasing the cat back and forth a few times at full throttle. That is when the oil leak come into play. The transmission does seem to shift firmly once TC is going. The driveline stops turning during stall test and stall rpm is same in all gears, forward and reverse. I haven't put a tach on engine to find stall rpm. I have to come up with a tach. I have just purchased the service manual. I am kind of leaning towards the reconditioned route if TC is determined to be compromised. I need to determine if a faulty TC is the source of the transmission fluid leak and not a flooding issue. What to do next is my dilemma. Thanks for your comments.
I wouldn't get to excited about pressures till you have a idea on torque condition. The old girls usually take a little bit to get going it takes a little while to fill every thing up one thing I will tell you it you get some one after you to check inlet and outlet pressure torque inlet is bench test only witch means that is max pressure allowed in torque to prevent damage to torque. On the machine you will only see that pressure on a cold start for a few seconds normal running it will be a good bit lower.
BTW what is the model number for the TC in a 46A, SN 21083, is it 1T0611?
It might be. Can you find a plate on the torque divider case.?
Serial No. 46A17130 to 46A22431 inclusive 7S7400 Pump, 1T670 Torque Converter
The old D8 46a and d9 66a torques are basically the same except for the impellor wheel, It was a1T633 on a d8 46a and 1T270 on a d9. When the 77v d8 came out they had a 1T270 wheel too I also think some of the very last 46a had a 1T270 wheel also I also find it amazing that this info is still rattling around in my head after all these years
There are some things you never forget. A lot of those fall into the category of "I thought everybody knew that". Apparently it turns out they don’t.
When I was a young fellow we did a lot of cat's mce transmissions and torques apparently I did too many d-8s and 9s cause there are also a lot of part number floating around in my head too
And so how do you know its the TC and not something else behind it?
Getting ready to work on the 8 next week. Going to drain oil from TC housing then go from there. I am wandering what I should put down on my shop concrete floor to drive on. Some say 3/4 inch strips of plywood or osb flooring should work.
Responding to "chidog" I don't know if TC is the problem, flooding may also be the source of the leak, I guess that would be a problem in the scavenge pump area isn't it? What is the universe of possible causes? I thought I would start by draining TC housing and measuring the volume of oil that comes out. Not sure what to do after that before I pull TC out and take it to town. Any guidance would be appreciated. Thanks.
I think first you need to post some pictures of the leak at starter. then check how much oil in torque, if it's excessive pull the scavenge pump and see if there is a problem with it. As far as the torque it is not rocket science back in the 70s we did a pile of them. doesn't take a lot of tools 3/4,1/2 and 9/16 socket 2 cat bars (pry bars) and a allen wrench The nut with the notches we always loosened with a blunt chisel and tightened the same way
How to check for stuff behind the TC. Checking using all the gears and brakes full on applied and full power, watch the drive line or u joints, do they turn in any of the gears? If they do turn its something behind the TC that is slipping.
Did you check the oil filters?
and don't forget when finally pull t/c case tie in with wire converter in into housing to stop falling out
I thought I would go out and do some cleanup pushing in the feedlot today. The thing will PUSH ounce e TC gets going. I checked the trans oil and it seemed to be going down on the dipstick but no oil was leaking out the bottom or around the starter as before. I later checked the engine oil (running) and to my chagrin the oil came up over a foot on the dipstick and was only a few inches from the top of the dipstick tube. I could see oil splashing down in the tube. I now know where the transmission oil is going! I am thinking that 1) it could be bad outlet relief valve, (not likely) 2) clogged scavenge pump screen. 3) bad scavenge pump 4) failed seal ring or 5) plugged magnetic strainer. I ran it for a couple hours so it can't be dumping a whole lot into crankcase. I think I will first examine strainer (I should have already done this but didn't) then try a pressure test at outlet relief tap. According to the book it should be around 40psi when stalled. Then lastly pull off scavenge pump and have a look see. Still hope it isn't sealing ring. It would appear Pittsburg Cat Man was right about it being a flooding issue rather than a TC problem. Would anyone care to rank possible problems by probable cause of leak?
I would start by cracking the engine oil drain and see what comes out. Since you have been running it how is the torque temp (gauge)
Try fitting a new Transmission Pump as yours is Knackered.
After reading the thread, did not understood what the complaints were?, nevertheless seen many diagnostics... In my modest opinion, either he "overhaul" both TC and TXM fit new pump ect, or he has to start by small things like fixing leaks, replace filters , clean screens and so on... probably neither of the solutions presented are the solution....
As the transmission oil is migrating into the engine it would be a common thought to expect the transmission pump to be a good place to start, so strip the pump and check the the bushings for damage, the next spot to check would be the torque oil level as oil can flood the case and get past the rear crank seal again filling the engine with transmission oil.
By "transmission pump" I assume you are referring to the "torque divider scavenge and torque converter recirculation pump" as described in the in the service manual that is located on bottom of TC housing, as opposed to the "hydraulic oil pump" that sets by the engine oil filters. Tomorrow I plan on dumping and measuring engine oil and TC housing, then inspect suction screen. Then I will do a pressure test on "transmission lubricating pressure". According to the book this should be about 15psi. I will keep you posted. Thanks.
If i were u i would start the house by its foundations.... there´s no point working on the roof... U got transmission oil migrating to engine sump, so before anything else u got to fix that, probably u got to remove the TC housing to replace crank main bearing seal, wile u´re at that inspect TC bearings and search for cracks in the pans,( its not the first time i heard of cracked pans) replace TC seals. Most probably the TXM charge pump is fitted of the TC housing, oil migration from pump is unlikely,(don´t know D8H arquitecture) but if it is a dry conection u got to replace those seals as well. After this is done u can start searching for pressures, as that charge pump pessure is also used for clutches and barakes, and it might well be a braking problem and not a TXM issue! Thing is the D8H is not a modular machine so... it will be a hassle to do all said above. Good luck
The transmission pump is located under the r/h front cab window next to the dipstick. It takes about 5 minutes to remove with a single 9/16 spanner. No oil will be lost. Then strip the pump and inspect it for wear. The shaft wears where the seal sits on it causing the shaft to groove out. It’s about the cheapest and fasting thing to fix on a D8 you’ll ever do. Be certain to check the suction screen seals as they go hard and suck air in.
Looks like oil can flow from TXM charge pump into engine sump, and it also looks easy to fix... not all is bad after all.
The scavenge pump does not power the transmission or the steering and brake function, the transmission pump at the forward position on the live drive case is the item needing a check.
I was able to do a little investigation into oil leak problem this last week. There was 25+ gallons of oil in the engine crankcase, and there was over 6 gallons in the TC housing and very little oil in transmission. Changed hydraulic and engine oil filters, scavenge pump screen was squeaky clean. This leads me to believe previous owner went down same rabbit hole, ran it for a while, then decided to sell machine. A sucker is borne every minute. I plan on doing a pressure test at tap "I" (16psi or so) the transmission lubricating oil line to confirm condition of that pump. Then it looks like the scavenge oil pump comes out and examined, then out comes the TC if there is no glaring fault with the pump. While in the vicinity I will consider changing out engine rear seal as it seems to be contained in an end cap of some sort rather than a two piece seal. The flywheel would have to come off, anything else? Can anyone confirm this on a SN 46A21083 machine. Thanks to "nicky 68a" for the pic, that helped to clear up pump nomenclature, but I don't think that pump is a problem (too bad) as it doesn't appear to dump bypass oil into TC housing. It dumps into the crankcase doesn't it? That would be too easy. Thanks guys for the input.
I'm pretty sure the rear drive for the pumps bolt to engine block not the flywheel housing rear pto shaft runs the whole way from front of engine so transmission pump is still a path to putting oil into engine check the seal on the pump and how bad the shaft is worn also on the scavenge pump one of the drive gears is keyed make sure it isn't worn off and spinning free also oil going thru crank seal would probably turn transmission oil black pretty quick
The transmission pump is driven off the engine and is bolted to the engine, the gear that drives it is lubricated by engine oil with the pump shaft and shaft seal in the housing on the engine, you take no notice of what I suggest that's is o.k. but I can point out to working on D8's for the last 50 odd years so have a fair idea of what is inside them, the rear crank seal changed to a piston ring seal and gives no trouble, the scavenge pump is easy to remove so crack on with that, the lubrication pressure is set by a small valve on the line to the brake cooling pipes so what you are going to find out at tap "I" is nothing but a waste of time, press on and good luck with your well thought out fault finding program.
Farmer I don't understand why you don't listen to Tctractors. He's one of if not the most knowledgeable on these dozers. Seems like a simple job to pull an easily accessible pump.
I had a boss like that once - “I have my opinion, don’t confuse me with the facts.”
Perhaps the clue is in the name of the op.
Hahaha ^^^^^ ! That one just made me spit coffee all over the screen. Unfortunately for me it took several seconds to marinate. LOL
Ah, the good old "coffee/keyboard interface"......
That was the funniest thing I heard in a long time . Reminded me of a guy who would'nt listen to 20 guys telling him not to do it, and wimping when they all laughed later. Simon C