Torque converter help

[Twisted]

I picked up a D65P-8 Komatsu at an auction to do some work around the farm. The previous owner said it was a good running machine that he just replaced the steering clutches in & the brakes needed some adjustment. I picked up a manual, adjusted the brakes, checked the fluids & took it for a test drive.
Now I am not a dozer operator by any means but have operated all types of equipment over the years so I have a very good feel for machinery including some old manual tranny dozers. This machine dosen't seem to push like it should. I removed one of the floor plates & can see it is the torque converter that is slipping. I am running the engine wide open & it dosen't seem to lose many rpm's before it stalls the tracks. It will push a load of loose dirt ok in 1st but won't cut much compacted clay. When I'm rolling across the field in 3rd & pull one of the levers to steer it, it will start to turn then come to a stop.
When I tried to check the pressures on the converter I got 2-6Kg/cm2 on the output side. The pressure rose as the rpm's did. Service manual says 2-3Kg/cm2. I could not remove the input test port. This makes me think there is a restriction somewhere downstream? Would that cause the lack of power or do I need a $10,000 converter?:Banghead
Any suggestions would be greatly appreciated.

Twisted.

 

[Dozer575]

So when it stalls, is the tc output shaft turning?
Check oil level, check for a plugged suction screen, does the tc heat up real quick?
If the tc output shaft is turing then the problem is the transmission.

 

[Twisted]

I verified that the tc output shaft is not turning when it stalls. I have not pushed long enough to tell if the oil temp is high. Only warmed up the machine & pushed a slot 3'-4' deep & 35' long to test. No climb in the temp guage after that.
What would cause the pressure to rise on the output side of the tc? even a plugged filter would relief at 1Kg/cm2. Would low flow through the tc because of a collapsed line or plugged cooler cause it to slip more?

 

[herbsupurb]

I'm only wondering if your torque convertor has a lock-up clutch inside of it and is either centrificully controld or by pilot oil some how. If you have the manual i would look at that. If your lock up is never working you will never be in direct drive, you will notice your engine will not bog down that much due to no power going to your trans from torque. As far as flow you should have 2 relief vavles, an inlet and outlet for you torque, maybe your outlet relief is set way low causing oil to just flow through torque and not do anything. NOT familar with your machine, just trying some basic items, hope this will help and good luck with it.

 

[tctractors]

Torque Talk

The Dash 8 torque is not a bad job to sort, as long as you are slim and not to tall, the cab can be a tad hard to work inside, the transmission pump is under your left foot when you sit in the seat, its worth popping it open and checking it's innard, bushing wear/damage being the common thing, not related but also common to fail is the drive shaft that drives the steering and transmission pump,(the gears wear on the shaft ) anyhow with a good pump and at any engine speed the short drive shaft from the torque to the trans,should stop spining once a speed clutch is selected, if it does but the tractor still has no poke (track spin in 1st at least,) you need to pop the torque out, firstly check the trans screen filter then drain down the main filter housing (plate on the inside edge of track hides drain plug) to check for bits, then remove under guard and drain oil from both the trans, and torque housing, on the front of the tran's at the lower edge is round plates, pop them off and check inside with your arm/hand for any bits, brass washers and chunks of circlips are the common finds,
Once all these little checks are done its time to pop out the torque, it lowers down by fixing a sling to the cab roof through both doors, then hang a pull lift down and fix a hitch point to the torque casing, its not a bad job at all to do, I always drive the tractor up on a few sleepers to make things easy to work on, the torque will come to bits easy, the things to check/replace are oil rings (like piston rings) and the bearings , the main bearing is in 2 parts both looking the same, on the outer edge is a V mark on both bits it is a "must" to get both V's pointing to each other, it should take about 2 days to sort this snag and have it working.
If you need any info or help, No Problem.

tctractors

 

[Sparffo]

I picked up a D65P-8 Komatsu at an auction to do some work around the farm. The previous owner said it was a good running machine that he just replaced the steering clutches in & the brakes needed some adjustment. I picked up a manual, adjusted the brakes, checked the fluids & took it for a test drive.

I really get pissed of when reading this...
this is excactly the same problem as mine:Banghead
read these treads also, maybe they give you some ideas!:
https://www.heavyequipmentforums.com/Forum/showthread.php?t=7114
https://www.heavyequipmentforums.com/Forum/showthread.php?t=7097

My Kommatsu won't pull reverse, or sometimes in first gear, and the forward is also lazy.
I got really good instructions from the Finnish Komatsu dealer, and hopefully i will get the filters tomorow so i can get trouble shooting.
It's quite hard to own a komatsu dozer here in Finland, they have sold totally 3 NEW komatsu dozers to Finland... and the importer didn't even know what a trackloader is ointhead
so it took me a while and plenty of phone calls to find some one who cared to help me with the problem.


IDEA!!!
should we start a club for people with Komatsu shifting problems? naaahh, i think thats a bad idea! who would make the first shift anyway? we would just try to slip away from work

 

[d4c24a]

tardis

if you pay tc enough of the folding stuff the tardis will be on its way to you
wherever you are
hope to see you this sunday tc
cheers graham

 

[Sparffo]

The Dash 8 torque is not a bad job to sort,
tctractors

Sounds like you have this thing in control!
do you know if the D41 has the same tranny? I have a D41s-3 series machine 1989 model.

 

[John C.]

Before you get crazy and start pulling the torque I would advise taking an oil sample from the transmission. If it's high in aluminum you probably have a problem. But if it's clean you should do some other checking first. You might even find you have the wrong oil in the tranny.

When those units go bad they usually create a ton of heat. You haven't stated what happens on the temperature gauge when the pushing gets weak. Maybe it's just hot oil. I have checked the outlet line on the converter and outlet line on the cooler with an infrared thermometer to see how much difference there is and just how hot it is getting. You won't learn anything by checking the inlet pressure. I wouln't worry about the outlet pressure your are getting at all. The usual problem is that there isn't enough because of internal leaking in the rotating elements. I believe the more the better up to a point. That also brings up another item. If I recall right there is a scavange pump in the bottom of the converter housing. If it quits the coverter housing gets slugged with oil and you loose ground power and create heat.

Pulling that converter will have you hanging up side down pulling wrenches at all kinds of odd angles. It is a job you want to avoid until you are absolutely sure you have to do it.

 

[Dozer575]

This is the one area where Cat really shines over Komatsu. I like Cats torque divider. It is a real positive feel for a torque converter/powershift.
The few things that can go wrong with the torque converter are, (1) major internal damage caused by something that came loose or was left in it. Like John says you will see lots of aluminum. (2) Fluid supply to it and from it. (3) Internal leaks (4) bearings
You need to check the suction screen/filters.
If I was going to spend 10k for a dealer torque converter, I'd go to a local machine shop and get one made from solid billet material. It would cost the same. I'm sure if it can not be fixed, there should be something used some place.

 

[Twisted]

Thanks for the very informative replies guys. I'll have to read through them again & make a decision on what to do. I would really like to hang on to this machine because it looks to be in really good shape otherwise. VG undercarriage, good sheetmetal, engine starts & runs great. The thing that scares me is for it to become a money pit. I called the dealer to get a price on a torque so I knew worst case & almost fell out of my chair when he said $7,500-$11,000 for a torque depending on my core. I didn't pay much more than that for the whole machine!

I guess I'll start with the easy stuff & work my way up. It's paid for & I don't need it right quick so I guess I'm gonna be a Komatsu mechanic for the time being. From what I have gathered, if I find "shiney oil" or "bits" where they aren't supose to be, I should button it back up & trade? Never had a torque apart & wouldn't be scared to if there aren't too many special tools needed. Is it possible to rebuild it myself for a reasonable cost? Dealer said they'll deduct 60% from the core if it appears that I tried to dissassemble.

 

[Twisted]

I messed up!

My dearest apologies to everyone who has looked at this thread. I forgot to post pictures! No one likes machinery pics more than me & it's just fair to see what we are all working on. Let's see if I can figure this out.....

 

[Dozer575]

You got a good deal, looks like not a high hour machine. And it is pretty straight. Looks like original paint as well?

 

[Twisted]

One more symptom. The tranny seems to have made extra oil. The stick shows a few extra inches & when I took it for a spin the breather dumped oil all over. I'm not sure where the level was before but the hydraulic tank seems to be a bit low now??? Does this make any sence at all?

 

[Sparffo]

sounds like the hydraulic pump has run it's hours...
when the pump is worn out, it starts to leak at the shaft. and the shaft goes in to the tranny!
that could also cause the lack of power, if they have hydraulic oil in it, then it will mess up the tranny oil also.
don't try to replace the seals in the pump, i would go for a new one! it should be quite easy to replace, it's located under the floor boards (at least on my D41).

 

[Twisted]

Now I may be getting somewhere. The hydraulics were fairly quick empty but when the blade was loaded it seemed to struggle some.

 

[AtlasRob]

Now I may be getting somewhere. The hydraulics were fairly quick empty but when the blade was loaded it seemed to struggle some.

Twisted, go back and read through the posts again. People seem to think you are being recommended to pop the Torque conv out. That is not the way I am reading things.
There are a lot of things that you are being advised to check before hanging upside down with a fist full of spanners Work through them and come back with the results, including condition of any oils you drop. and good luck :drinkup

 

[tctractors]

Twisted Torque

Twisted it looks like you might have found your snag?? the correct oil in the hydraulic system is 10w so a bit in the transmission is not the end of the Earth, as you will be draining the oil out anyhow, just thought I would say that often when a komatsu torque starts to play up they don't clash about like a Cat unit, and can often be repaired via a set of bearings and oil rings, I always check all the parts of the transmission before ripping it to bits as the customer always wants to know how it stand's on the $$$££££ side befor he gets in to deep, I hope you dont think I am inducing you to pull what looks like a great ride to a heap of nut's and bolts, anyhow in the U.K. there is a few good Co's that sell new and used items for Komatsu kit that dont ask total joke money, I can offer there names if it may help you,

tctractors

 

[Twisted]

Twisted, go back and read through the posts again. People seem to think you are being recommended to pop the Torque conv out. That is not the way I am reading things.
There are a lot of things that you are being advised to check before hanging upside down with a fist full of spanners Work through them and come back with the results, including condition of any oils you drop. and good luck :drinkup

You can believe me when I say the last thing I want to do is drop the torque on this machine. The two main reasons for consentrating on it are 1) the torque stops when the tracks stall & 2) that should be the worst case. I wanted to know what I could be getting into before I started to sink money into it especially if I was just going to trade it off.

There have been many great suggestions on how to trouble shoot this problem & I will have to read through them a couple times to insure I completly understand what is being said.

I'm off to the woods with the wife for a weekend of riding ATV's so prolly won't be much wrenching going on this weekend. Tough decision hugh?

I'll try to do a little work on it tonight & ponder the findings over a couple beers.:drinkup

Thanks again to everyone!!!

 

[tctractors]

D4c24a

See you at Ketton then Graham.
tctractors