550G Dozer Torque Converter Leaking

[darrenrudolph83]

Hello All!

I need some help on a 550G dozer.... It is leaking transmission fluid from the inspection plate on the bottom of the torque converter housing. It is leaking at a steady stream while working the machine. I am going to pull the engine to fix whatever is causing this issue, my problem is I am not getting much help from my local JD dealer, online manuals or the manual I have at home....

I can not find in any of my manuals the inspection plate with two bolts listed anywhere other then it mentions it briefly in the section to remove the engine and trans.

I do not see an input shaft seal or any seals for that matter for the torque converter that could be leaking... The dealership was going to call me back twice last week with part numbers but no luck yet.

What am I missing?? I do not want to tear into it until I know what is in there, I cant find much info on these dura-shift torque converter transmissions. Surly others have been into these or have seen them leak like mine.

I would hate to pull the engine and trans if it could be something that I could fix without doing so, output shaft seal, O-ring or something in that nature, I just assumed all this time it was the input shaft seal.... I cant seem to find one though.

Thank you for any help, comments or anything.

[Jim B]

Hi Darren,

Hopefully someone who has been into one of these will weigh in, best I could do was look through the on line parts catalog. I didn't spot a plate in the bottom of the converter housing in the parts catalog either.

It looks like the converter/flywheel area should be dry. It looks to me like the converter itself, has a couple O-rings where the sections bolt together. There is a ring, which may be a sealing ring like a piston ring, (JD's latest changes to the parts catalog took away the ability to see details on many of these type things some of us had through our accounts.) on the stub shaft on the output end of the converter. If that is what it is it would seal inside the converter housing. The converter housing has a seal at the output shaft where the flange for the driveshaft to the transmission exits the housing. Likewise there are seals on the input shaft of the transmission, behind the driveshaft yoke.

If that is a metal sealing ring on the converter stub shaft look closely at the surface it runs in. If that has a groove in it, that could leak even if the ring is not broken or appearing worn out. I had that issue in a CAT TLB where the forward reverse clutch shaft sealed in the transmission housing. Ended up having the housing sleeved in the worn area. Luckily the service guys at CAT had seen it before and worked with a local machine shop on the fix. They told me the shop they used, who to talk with there, and to tell him he could call them if he needed any info. A new housing would have been a couple grand more than the repair.

Have you had any floor boards up? Can you clearly see the leak and are sure it is not running down there from something else? If the leak is coming from the end of the converter housing where it bolts to the engine I would be taking converter seals, bearings, and bushings with me. You likely will want the bearings and seals for the converter housing output shaft as well.

What manuals do you have by type and publication number? This isn't much help, but what it looks like to me based on the parts catalog.

Jim

[darrenrudolph83]

Hi Darren,

Hopefully someone who has been into one of these will weigh in, best I could do was look through the on line parts catalog. I didn't spot a plate in the bottom of the converter housing in the parts catalog either.

It looks like the converter/flywheel area should be dry. It looks to me like the converter itself, has a couple O-rings where the sections bolt together. There is a ring, which may be a sealing ring like a piston ring, (JD's latest changes to the parts catalog took away the ability to see details on many of these type things some of us had through our accounts.) on the stub shaft on the output end of the converter. If that is what it is it would seal inside the converter housing. The converter housing has a seal at the output shaft where the flange for the driveshaft to the transmission exits the housing. Likewise there are seals on the input shaft of the transmission, behind the driveshaft yoke.

If that is a metal sealing ring on the converter stub shaft look closely at the surface it runs in. If that has a groove in it, that could leak even if the ring is not broken or appearing worn out. I had that issue in a CAT TLB where the forward reverse clutch shaft sealed in the transmission housing. Ended up having the housing sleeved in the worn area. Luckily the service guys at CAT had seen it before and worked with a local machine shop on the fix. They told me the shop they used, who to talk with there, and to tell him he could call them if he needed any info. A new housing would have been a couple grand more than the repair.

Have you had any floor boards up? Can you clearly see the leak and are sure it is not running down there from something else? If the leak is coming from the end of the converter housing where it bolts to the engine I would be taking converter seals, bearings, and bushings with me. You likely will want the bearings and seals for the converter housing output shaft as well.

What manuals do you have by type and publication number? This isn't much help, but what it looks like to me based on the parts catalog.

Jim

Jim,

Thank you again for your reply! The books I have are parts catalog PC2154, Technical Manual TM1404, Operation and service manual OMRG18293 and the JD online ones you sent me the link to last time when I was digging into the engine. I found the bottom plate lastnight on one of the manuals and was able to confirm like you said the converter/flywheel area should be dry.

I found a seal part# YZ101507 that looks to possibly be the input shaft seal that I was thinking was the problem, I cant find any pictures of it online though. I was able to also find the O-ring part numbers for the hydraulic and transmission pumps that mount to the rear of the trans.

I have had the floor boards off, I also removed the two belly pan / access covers from the bottom of the dozer and cleaned everything up real well so I could know exactly where it was leaking and it is for sure leaking from the small inspection cover on the bottom of the torque converter housing. I am betting it is the seal YZ101507. Just thinking out loud if the converter itself was leaking it would be losing pressure and not functioning properly, the dozer pushes strong in forward and reverse and in every gear. Am I correct in that thinking?

[darrenrudolph83]

The inspection plate part number is R121039, it can be seen if you search the online parts manual.

[Jim B]

Your 550G is like my 450E as far as manuals go. You need the second technical manual to go with the one you have. TM 1403 is the first of the set. It has most of the operational function and testing information. TM 1404 is the nuts and bolts repair info. https://www.johndeeretechinfo.com/searc ... attr=p0,p1 .

I checked that plate number R121039 and I see it today.

I believe you will find that seal, YZ101507, is a metal sealing ring. Yes, it could be the problem. Another thought is a seal failed on a hydraulic pump, mounted on the housing and driven by the converter, is overfilling the converter housing. I don't know if you said, but I expect you are having to add oil to the transmission, not the hydraulics.

The converter is common to all gears forward and reverse, so they would all be weak in some respect if it was losing much oil from places where it bolts together, it would seem.

[darrenrudolph83]

Your 550G is like my 450E as far as manuals go. You need the second technical manual to go with the one you have. TM 1403 is the first of the set. It has most of the operational function and testing information. TM 1404 is the nuts and bolts repair info. https://www.johndeeretechinfo.com/searc ... attr=p0,p1 .

I checked that plate number R121039 and I see it today.

I believe you will find that seal, YZ101507, is a metal sealing ring. Yes, it could be the problem. Another thought is a seal failed on a hydraulic pump, mounted on the housing and driven by the converter, is overfilling the converter housing. I don't know if you said, but I expect you are having to add oil to the transmission, not the hydraulics.

The converter is common to all gears forward and reverse, so they would all be weak in some respect if it was losing much oil from places where it bolts together, it would seem.

Jim,

I was not aware of the other book TM1403, I will purchase that one now haha! Pretty soon ill have as much wrapped up in books as I do the dozer....

I was thinking about what you mentioned above in regard to the seal failing on one of the pumps. There is the hydraulic pump and the transmission pump that are both mounted to the rear housing... If a seal failed somewhere in the transmission pump side could that cause fluid to leak from the torque converter side? If so what would be the path? I suppose if it over pressured through the converter it would most likely still come from seal YZ101507 correct? And if that's the case it more then likely is washed out to some degree and will still need replaced.

I am having to add transmission fluid, I also have confirmed it is leaking from the torque converter housing through the lower inspection plate. It does push strong in forward and reverse so I am really leaning towards seal YZ101507 rather then anything within the converter itself. I could be wrong and have been many times before

[Jim B]

I don't have any manuals that show that set up or its flows, just the parts book, so most of this is speculation. The converter has to have a flow of oil into and out of it. I expect that comes from the transmission oil system. That seal ring, YZ101507, on the converter hub may be it. Looking more at the converter housing drawing there is an oil seal, YZ106527 (sub for YZ101641) that looks like it may also seal on the converter hub. I agree, a leak at the converter hub is most likely, with the oil leaking into that flywheel/converter compartment.

If the 550G TM1403 manual is like the TM1330OP (Technical Manual Operation and Tests) for the 450E it will have the flow paths mechanical and hydraulic in it, (descriptions and drawings). For the 450E the second manual is TM1330RE (Repair) and has the nuts and bolt info in it. So I am guessing you will find similar with the 550G manuals.

The E, G, and later series of all models are getting to the new side of the machines here, so there aren't as many familiar with them. Hopefully one of the guys who has been into one of these will be along with some info for you. I will say the old 430 I had was a lot simpler to deal with in many ways.

[darrenrudolph83]

Jim,

I sent you a PM.

Thanks
Darren