555A no movement or hydraulics

[jonesrj]

Let me first say I'm very happy to have found this forum. Thanks to Lavoy and many of the great members who share a wealth of information.

I recently bought a 555A crawler that had been used in a landfill at near scrap price. The muffler had been left off it for some time so the engine was stuck. Due to a lot of negativity I found when reading about the powershift transmission, I wanted to try to get it running and check the transmission before pouring a lot of money into the engine.

We got the engine freed up (thanks to Kroil) and with some new injectors I heard the engine run for the first time yesterday. The engine ran surprisingly well. The bad news though, is there is no hydraulics or transmission movement. It's like the engine is disconnected from the rest of the powertrain. After looking in the service manual and the parts breakdown, I'm guessing there is something wrong with the spider gear on the input of the torque converter. But I've never owned or worked on a JD crawler before this one, and only know what I've read here and in the manual.

It seems to me if the body of the torque converter was being turned then I would get some hydraulics or transmission pressure??? I guess the other possibility would be the pump drive gear on the back end of the converter. Do both the transmission pump and loader hydraulic pump run off this one gear?

I would love to hear any suggestions or thoughts on what might be wrong.

Assuming it is something wrong with the converter (input side or pump drive gear), where will I need to look for parts? I looked at the spider gear from John Deere and all those parts are showing as not available. I didn't check the pump drive gear. Will a good torque converter shop be able to get these parts if I have the converter built?

I'd like to get the old girl operating again, but I don't want to break the bank doing it...

Thanks a lot.

[west25346]

I just rebuilt the transmission in a 550A dozer spent about $1500 in parts. Parts seem to be readily available (aftermarket and through dealer) also found several machines in salvage yards for parts. The transmission pumps are not available through aftermarket suppliers anymore. Can you get any information from the previous owner? Have you tested for pressure in the transmission? Good luck

[jonesrj]

West, thanks for the reply. That is certainly encouraging to hear about the transmission rebuild. What all did you have to replace? I was reading another poster here talk about checking and reusing the steel rings in the clutches and only replacing the sintered disks. With about 60 disks total at about $25 a piece any of the steels that can be reused is a good thing.

Can you get any information from the previous owner?

Unfortunately no. The municipality that sold the machine is not the one that owned it, and I couldn't get any real info from the folks I talked to.

Have you tested for pressure in the transmission? Good luck

I didn't hook up a gauge to the transmission, but the machine didn't budge in any gear. The pressure gauge in the dash didn't wiggle or anything. So with no loader hydraulics and nothing from the transmission at all, I'm guessing something wrong with the torque converter input. I plan on taking the top off the converter housing to check for rotation. Also going to pull the plug out of the bottom of the converter housing and check for rubber bits or any other debris. I meant to check the transmission filter for metal or clutch shrapnel last Saturday, but ran out of time. I'll do that too this Sat.

[Tigerhaze]

The pressure gauge in the dash didn't wiggle or anything.

FYI those dash gauges ore often inaccurate or inoperable- testing using a hydraulic pressure gauge directly hooked to the testing port on the transmission is the most reliable method as you can see how pressure changes with shifting. However the steps you indicated seem reasonable as a first check.

[west25346]

The plate the brake hinges on is over the top of the converter and you can see the rubbers there. I replaced all the plates in directional clutch and all plates in the first range clutch . Plus all the piston rings (steel and fiber) on all the clutch packs. I had to replace the 1st drum assembly with a used one, the sealing rings had worn the groove oversize. Found out afterward the dealer sells oversize rings (oversize in width) so the grooves can be cut wider on the shaft. The parts book shows oversize rings but has no description.Would have done that at work if I had known. So now I have a spare 1st/2nd drum.The wider rings are $31. each vs $8. for the standard ones. I tried to get some information on this site before I purchased the machine...did not get any replies. So if I can help let me know. Other posts say you can access the clutch packs from the top...it's not the way it works. Had to remove engine,torque converter housing to get to transmission.Really like the way the machine pushes dirt, the older service guys who worked on the machines back in the day told me the 550 had an undeserved bad rep for service. Dont know, this is my first 550 series dozer.

[jonesrj]

Thanks Tigerhaze. I will definitely inspect pressures closer if I find the converter is actually turning.

[jonesrj]

Great information, thanks West. It seems you pretty much did an entire overhaul on the transmission, that is encouraging. I too noticed the oversize sealing rings from JD, but I was assuming they were oversized on the diameter only and not the width, so that is good to know.

Assuming I have a torque converter drive problem and you were in my shoes, knowing what you do now would you go ahead and pull the transmission while you were in there, or just fix the torque converter and cross your fingers on the transmission? I guess what I'm asking is how troublesome would it be to tear it all back apart if I find out later I have a trans problem too. Of course the loader frame vs dozer blade may not be direct comparison as far as aggravation related to pulling engine and converter housing.

I had read on here too about working the clutch packs from the top rather than pulling engine and torque converter, and the manual mentions it also. But after looking over the transmission rebuild in the manual I had already decided to pull the whole thing out if I need to rework the transmission.

[west25346]

I made the same mistake when reading the tech manual.If you reread the section on the transmission it says you can remove/service the clutch packs without removing the transmission housing from the machine.There is no physical way to remove the clutch assemblies from the top. How far you go with the tear down is your choice. If you pull the torque converter the housing is not much more work, then the plate on front of transmission when removed allows access to the clutch packs. What is your plan for the machine? How comfortable would you be removing the engine,converter,housing , etc again if you assembled the machine and discovered another issue in the transmission? It was enough of a job I am glad it only had to be done with one shot.

[Tigerhaze]

I can't say it is the same concern with a torque converter in a crawler as in a auto or truck, but usually when the torque convertor fails it spreads contamination and debris throughout the transmission too. At a minimum I would want to completely flush the transmission if the torque convertor failed. Just a thought.

[jonesrj]

Eureka! west, you know I've never worked on one of these transmissions, but I have worked on quite a few others syncrorange, etc, and I kept thinking "how are you going to get those shafts out from the top of the trans??" But after you explained that statement makes perfect sense now. You can either pull engine & converter to get the guts out of the transmission, or you can pull engine & converter and trans housing and build it on the bench...is what the manual is trying to say. HA! Clear as a bell now.

I'd like to fix it and use it on the farm, or maybe clear some land in the future. Either way whether its this machine or another, I'll have a loader for that purpose. It certainly wouldn't be used every day and I won't be loading out of a pit with it.

How comfortable would you be removing the engine,converter,housing , etc again if you assembled the machine and discovered another issue in the transmission? It was enough of a job I am glad it only had to be done with one shot.

This is really what I was driving at with my question. If I only go into the converter and fix it, and still have a transmission problem, I'd probably be more inclined to sell it as is or junk out instead of going back into it. Probably need to just pull the transmission and go through it all at once. Just don't want to spend more than about $3000 to get her fixed. My labor is free...

I haven't yet committed myself moneywise to the machine i.e. I could quit now and still not go in the hole. And really that's the source of all the waffling and wondering. I guess I just got to tear into her and see whats what. I can explode the transmission, take inventory of whatever damage might be there and get a estimate for parts before I commit either way.

I really appreciate your help.

[jonesrj]

Thanks haze. I'm anxious to get to her Sat. and do some more diagnostics. I can imagine that if the drive coupling is the culprit, that the guts of the converter may still be intact and maybe has not yet contaminated the trans. However your point is still a good one.

West has about convinced me that in any case I need to pull the transmission and tear it down even if its ok. I would sure as heck hate to fix the converter and then find the transmission is wore out too.

[Tigerhaze]

BTW, have you read the archives on here about 550s/555s? There were quite a few good posts about transmission swaps and repairs for them that included Digitup2s perspective (he's a commercial user of the larger crawlers). I think that would be good "food for thought" in your quandry. Just use the search function at top right and search for "555".

[jonesrj]

Yes, I read everything I could find on the early 550/555s. Reading posts from Digitup2 was quite encouraging as it seemed all the others talking about the 555A transmission were so incredibly negative with little explanation as to exactly why.

[jonesrj]

Parts seem to be readily available (aftermarket and through dealer) also found several machines in salvage yards for parts.

Hey west, curious about the machines you mentioned in junkyards. Were those yards local to you (i.e. within driving distance) or something you found online or otherwise ordered? Just wanting to gather as much info as possible...

[west25346]

One machine is within driving distance others are not.I have the dozer with 6way blade not the model you have.I left the transmission housing in the machine when rebuilding the transmission.Until you find the problem its just a guessing game on repairs. You would only be out 3 hours or so if you had to remove engine,torque converter,etc again. I can usually disassemble something a lot faster the second time around. Plus you could put together just enough to see if it solved the problem to save time.I don't want to sway you one way or another, i'm like you labor is free and the parts $ start adding up fast .