D7E 48A5008 Dozer: First time for me to see it. It is migrating Engine oil into the transmission, and whatever the engine oil goes down the transmission oil goes up. Found out he had a company change the front seal and speedy sleeve. They did not even check the crankcase breather pipe vent and it has not been apart in a long time. Think it blew the front seal first, and now the worn rear seal is dumping also. Any other place that I don't know about that the engine oil can get into the transmission via the torque. This is my guess so far. Anyone else know differently. Simon C
Is your transmission oil getting black?
Yes he changed it, and it came back black again. Rear seal from what I understand. Simon C
Yes not many options for oil going that way
That what I thought for black motor oil getting into the transmission. Thanks for the response. Simon C
The stering cluch pump at your right feet could be the probleme
That pump which I seen is in the gearbox housing and gets turned by a gear, that gets turned by the flywheel from what I understand. How could it get engine oil there. They wouldn't use engine oil to lube the bearing ends of the gear drive shaft. Don't think it is possible, but never had exact model apart. Believe torque oil lubes everything in the housing. Simon C
I had some D7E in 1982 and remember we had removed one of these pump for changing a oil seal because she make a suction motor oil
I can't say you are wrong as I have never had that torque off before and don't even have a parts book. The pump is high up on right hand side of housing when looking at front of machine from drivers seat. If the housing was lubricated with Engine oil, then you could be correct. I am hoping that someone that has taken many of these torques off before can say how it is made inside. Thanks for your reply. Simon C
I agree hard to grasp it going thru pump I would think it would suck more air than oil. try this for a parts book https://www.tractorparts.com/PDFs/CAT_D7E_TRACTOR_48A1_AND_UP_PARTS.pdf
Hard to suck oil through a straw versus air. If oil was getting into that housing for normal lube, it would easily go into torque, I believe that is why the rear seal is double lipped. In fact when doing Dyno runs on some of the big stuff we used a temporary rear seal as we use to take one gear out of the gear train to prevent the pump from turning and burning out. The rear seal was getting no lube other than what we put into it for the run. We were using a double lip rear seal as we did not have a single lip rear seal that would get lubed by the crank splash. Since the pump is at the top, the housing would have to be full to the top for the pump to suck it in. If I have missed anything let me know. Responses appreciated. Simon C
I am not a mechanic men but if am remember this pump was bolted on housing like you said and have spleene shaft and she had at bottom front cover 2 hoses or pipe for oil circulation.
Like this
Maybe they had lube pipes lubricating the pump drive with engine oil. I hope someone who has unmounted half a dozen of these and put back together can shed some light. The picture shows some pipes, but not in multiple directions. Old service manual would tell all. Maybe TCTractors would know. Simon C
Looked through Post number 10 pictures and on Pg.30 of 8-64 there is a slinger on the maybe flywheel that is part number 7F4363 which is maybe to oil the gears in PTO housing. I did not see any internal pipes providing lube for the bearings on the shafts. On Pg.9 of 7-64 the PTO housing is there for this 48A5008 ser# and I could not see a seal there that prevents engine oil from going into the transmission. Just trying to get the scoop on this before the guy pulls all the stuff out of the way and the torque out to get to rear seal. In other words if there is something at the steering pump that is doing it, how.? Pump would be a lot easier to change out. Simon C
You are talking pretty old history go down to partsbook page 29 CAT puts crank seals on the crank picture. Also on this they list different seals for oversize crankshafts Also check page 87 the seal is in the pump. I've been thinking if i remember right there were changes that took tran pump off torque and put a plate over hole and there was plumbing changes Check and see if there is a pump bolted to upper part of torque facing the transmission
Thanks for the reply pittsburgh cat man. Will check it out. I helped change a head 43 years ago, but that is it for these old girls and my experience. Simon C
Seen the crank seals on pg29 as you posted above. Yes there is the standard size seal and then one other for the cranks that had been cut. The seal area looks like a weak spot to me. If the pump shaft was leaking it would take a long time to suck enough dirty engine oil to make all the clean transmission oil black. But a leaking rear seal could do it in 1 day. I will have to check the pump locations as you mentioned with the floorboards off. Maybe there was some changes. Simon C
a long time a go had ,D9H engine leaking oil in to converter via rear seal ,and make up dash 4 hose with a fitting silver soldered up and drill small hole drill through adjusted till oil remains at correct level ,was meant return to the workshop ,went on 4week break and it was still working
Kind of late to the game here, but the first and easiest source of engine oil to look for is the transmission pump. The seal on the drive side fails (or is installed backwards during a repair) and the pump sucks oil out of the accessory drive. The second source is the rear main, but significantly less likely. The pump seal is a fairly easy fix, and significantly cheaper than replacing transmission oil a drum at a time. Hard to believe but it doesn't take much engine oil to turn the transmission oil black. If you want additional assurance, head over to ACMOC and ask Old Magnet to explain it to you. My experience comes from dealing with this problem in the 7E's larger cousin, the 8H and 8K.
So the steering pump is i believe at the top right when sitting in the seat. Is splash oil the oil you are saying is getting sucket into the pump. It is all together possible but keep in mind the crankcase vent has never been cleaned. He is going to clean and run a test with both oil levels starting perfect. Plus no one here has verified the the gear train is lubed by engine oil versus transmission oil. Not saying your wrong, but the first test will have to be done. So did they use engine oil or transmission oil in 8H, 8K units to lube the gears in gear train. Is it the same in the 7E, not even sure of. Simon C
Scratching the noggin a bit at the mo. Pretty sure only 3 types of oils were used in these machines, engine, transmission/ hydraulic and gear oil, SAE #30, 10, 90. So I'm thinking the trans oil is different to the engine. But I could be wro wron wrong.
The question no one has been able to answer with certainty yet is whether or not the gear train is lubed by transmission oil or engine oil. If it is by transmission oil then the problem is from the rear seal in my mind. Looking for a 90 year old with good mind that removed a dozen of these torque convertors. Simon C
Bad engine rear seal.
I think and hope you are correct. Waiting on the 90 year old to answer, or someone else that has owned one and had apart. Simon C
Engine oil. some d7e ran tran pump off torque and a steering pump off drive on engine PS I ain't 90
Had it on a 46A and kept running it we had jobs to do. My fix remove the plug at the top of the transmission pump install a nice little valve and a rubber hose. And keep an eye on the engine oil level while operating it, when it got low put the hose in the filler and pumped the oil into the engine. Yeah when clearing you sure don't want a stick smacking that valve, you take a bath. LOL Years later removed the engine to do a rebuild and the seal was not in good shape. Doing it insitu would be very difficult. The oil transfer was worse when operating with the nose high, so always tried to keep the front of the machine low.
Know you are not 90, and will see the inside of it by November when it goes into a shop. Like Chidog's solution to keep it going. Simon C
Just thinking as little as it would take to remove the pump disassemble and check the pump and it might save you from removing the torque I think I would pull the pump first
The accessory drive that drives the transmission pump is lubed by engine oil. You can see that it is part of the engine and separate from the transmission if you pull the floor. On another note, you were wondering if a leaking pump seal could turn the transmission oil black in one day. The answer is yes. A little carbon black goes a long way.
Either way is ok. We just need to know if the pump seal was the problem after he installs a rear main so we can remind him how much easier pump first, main second would have been.
Working backwards on you posts. Yes. I'm saying engine oil is getting sucked into the transmission pump. The pump has two seals that face each other. Seal on engine side faces pump. Back side of seal keeps engine oil in accessory drive. Seal on pump side faces engine. Back side of seal keeps transmission oil in pump. What's hard to believe is that engine oil can get past the pump seal due to the higher pump pressure, that's what happens. The pump pulls it right past the pump input shaft when the engine oil seal fails. This is why I suggested asking OM. He's an engineer and has all the technical info. I'm just going off of what I've experienced and the Cat mechanics who told me what was going wrong. 8H46A and 8K77V accessory drives (powershift) are the same as the drive in the 7E48A (powershift).
Pulling the pump off first would definitely be the simplest and logical thing to do if the gear train is lubed by engine oil. Worth having tested and who knows what a guy will find once apart. Thanks for the response. Simon C
Check-Brake is giving you the right info. Transmission pump is driven from auxiliary drive which is lubed as part of the engine. A failed seal will result in cross contamination. Also if you replace the pump you need to trim about 1/8" off the new splined shaft. If you don't there will be an interference fit between the worn drive splines and the new pump shaft that will result in excessive thrust that will wipe out the new pump.
Yes could be I suppose the pump seal. In my case it was the rear seal. And sure pull the pump very easy. Much more so than rear seal. Not sure on that engine, but a quick look at my old small paper back size, D8 manual, shows an engine out and crankshaft out job for the rear seal, newer D342's maybe different, its been years since doing that job, but it looks like the rear main hooks over that seal to hold it. Please correct me if I'm wrong.
Thanks for that information as not too many have worked on these units and still remember or are still alive to relate pertinent details. I understand what you are saying about the new pump shaft that will have no wear and it will push the piece it goes into removing any free play. Zip disc off 1/8 of an inch and taper the first 1/8 of an inch to prevent this from happening. Response much appreciated. Simon C
This is a D7E and I don't believe it is a D342 like in the D8H or D8K Dozers. I kind of wondered about the rear seal also. If it is gone wondering if Check Break or Old Magnet have been there or seen it done before. Would appreciate some input. I am not doing all of this job, more like consulting supervising. Simon C
Post #10 has the engine breakdown and this is only a 4 cylinder engine not the in-line 6 engines. From what I seen it looks like it is a crank out job to do the rear seal . Hope someone says otherwise, but this guy will be starting with the pump first as it is the easiest and cheapest after he cleans out the crankcase vent. Simon C