Brand new to Yanmar and this board. I've owned two 8n's and an old D-6 from the Alcan Highway, but still "new" to this 40 year old technology. This question may be a little pre-mature as I am waiting on my manuals and haven't any resources other than online to troubleshoot the problem myself. Hoping someone has simple answer, or can point me in detail where to look. Bought this 187D that has obviously been neglected. The dealer told me the brakes were dragging, hence the reason it just didn't seem to want to "go" when under power. They also said someone had added gear oil to tranny, which made it sluggish. The yard was flat where I test drove and it did okay, but definitely not as fast or as quick to respond as it should. I confirmed brakes were stuck before I bought and was hoping this was the problem. Simple fix, I thought. Once I trailered it home, I removed brakes completely from both side, and sure enough, rusted solid. Test drove with brakes out hoping that was it. It wasn't. I actually had my doubts as soon as I unloaded it as my property is sloped and the thing rolled freely down the hill until I dropped the bucket. That was my first clue it wasn't the brakes holding it up. So now, my question is, what is it? It doesn't seem like the clutch. I have had slipping clutches before, and they usually seem to just slip the more you use, or the more power you apply. This feels as if the thing slowly builds up the more power you apply and the longer you wait and then limited power finally gets to the wheels, but still isn't right. Will barely climb the slightest slope. On flat ground isn't too bad. Best in 2nd gear, mid-range. Engine starts and runs great. What it reminds me of is an old Ford I had with a leaky automatic tranny that when it got a little low on fluid, the car just didn't want to go until the fluid pressure built up from the little fluid it had. Add fluid and, bam, back in business. I have no idea how the "power shifter" on the 187 works. Is it a fluid type auto tranny? I'm actually a lot confused on the two "trannys" to begin with. The basic one on the floor is pretty straightforward, but the "on the fly" power shift on the steering column, I don't get. I mean, I get what it does, I just don't understand how it does it. Is it an electronic shift like a split axle, or an entirely separate transmission? Can't wait to get my manuals, but any insight before then??
Just won't go
- Thread starter heloman88
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careyo63
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Gear oil may be the reason or who knows what was added. But my guess Is the pickup screen dirty. Clean Tans. Hyd. is most likely needed. You Can easily clean and replace it. Your Man. will go over it.
HYDRAULIC SCREEN: Yanmar Tractor Parts
HYDRAULIC SCREEN: Yanmar Tractor Parts
clemsonfor
Super Member
Like cary said clean the screen/filter. I bet it's plugged solid and gear oil is like 3x to thick. It runs on tractor transmission fluid, 303 spec, or you can use automatic trans fluid
normde2001
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Does the PTO work as it should under a load? (eliminates clutch slippage). If changing trans oil and cleaning screen do not fix it's probably a bad power shift relief valve spring, accessable externally in transmission.
California
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The shifter on the right side is three ranges. Like a Jeep that you shift to low range for heavy going, to give an example. Think of the three as Road Gear, Second Range where you will do most heavy pulling, and Low Range for creeping with a rototiller.
Then (logically) behind that range transmission is a second transmission, the Powershift. It is near identical to an automotive 3-speed automatic transmission - clutch packs engaged hydraulically, planetary gears, etc. But one big difference: There's no torque converter.
Move the dashboard shifter. After a moment hydraulic pressure builds and engages a clutch pack, and off you go with a direct mechanical connection from the engine to the rear axle. The internal hydraulic clutches soften shifting, but if you come to a stop still in gear you will stall the engine. You can shift without clutching but most of us soften the shock on the transmission by using the clutch pedal in the normal manner.
Another characteristic of Powershift is you can let the clutch out in Neutral and get a heavy rotary mower or rototiller spinning without moving the tractor then shift into gear to start moving.
Thanx for the quick replies and suggestions. Not sure about the PTO under a load yet as I don't have anything to run on it. I'll flush the tranny and clean the screen and give an update in a few days. Thanx again
Sorry for delay in updating, had some things - family - come up. Did the flush of tranny fluid, cleaned the screen (wasn't really that bad, a little slimy, but not clogged), changed the spin on hydraulic filter as well. I was actually disappointed when I saw the screen as I was hoping it was clogged solid and that would be the problem. When I saw it, I knew it wasn't. I even fixed my brakes which were frozen/rusted solid.
Verdict: much better than it was, but still not right. It definitely is sluggish in the power getting to the wheels. Doesn't matter if in 4wd or 2wd, forward or reverse, although I usually leave it in 4wd. I give it throttle and it just sort of sits there for 3-4 seconds, I can feel the power building (not the engine...it runs strong), then finally it begins to go, and then really go. Sort of makes it difficult to fine tune positioning a load of dirt with the scrapper. I have noticed if I am backing up a slight grade, it can take 4-5 seconds or longer to finally get going, and then if I make a gentle turn as I'm backing - which puts an additional load on - it slows slightly and has to build again. All I can figure is, it's got to be something to do with the clutch packs. It isn't the dry clutch slipping, I'm pretty sure. Engine would over speed and giving throttle would make it slip worse. This is the opposite of that. It's usable as is, and I plan to keep using it until this winter when I guess I'll have to open it up and see what is going on. Any one ever experience this and it not be the tranny screen?
Verdict: much better than it was, but still not right. It definitely is sluggish in the power getting to the wheels. Doesn't matter if in 4wd or 2wd, forward or reverse, although I usually leave it in 4wd. I give it throttle and it just sort of sits there for 3-4 seconds, I can feel the power building (not the engine...it runs strong), then finally it begins to go, and then really go. Sort of makes it difficult to fine tune positioning a load of dirt with the scrapper. I have noticed if I am backing up a slight grade, it can take 4-5 seconds or longer to finally get going, and then if I make a gentle turn as I'm backing - which puts an additional load on - it slows slightly and has to build again. All I can figure is, it's got to be something to do with the clutch packs. It isn't the dry clutch slipping, I'm pretty sure. Engine would over speed and giving throttle would make it slip worse. This is the opposite of that. It's usable as is, and I plan to keep using it until this winter when I guess I'll have to open it up and see what is going on. Any one ever experience this and it not be the tranny screen?
California
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Has an amateur been into that transmission before?
There's a feature in the Powershift that provides some braking when the tractor is stopped in neutral. I think this is so the tractor won't roll away with the dash shifter in neutral. Those clutch packs always have some drag and the brake counteracts this. It may select two gears at once or something to provide the braking. The braking was barely noticeable on the YM186D I sold, more noticeable on my present one.
It is most apparent when the engine is cold and the PS is in high range. Letting out the clutch cold loads down the engine noticeably more than just moving the tractor would cause. (This may also be why the manual calls for a five minute warmup).
If this braking feature were out of adjustment, it could cause what you describe.
There's a feature in the Powershift that provides some braking when the tractor is stopped in neutral. I think this is so the tractor won't roll away with the dash shifter in neutral. Those clutch packs always have some drag and the brake counteracts this. It may select two gears at once or something to provide the braking. The braking was barely noticeable on the YM186D I sold, more noticeable on my present one.
It is most apparent when the engine is cold and the PS is in high range. Letting out the clutch cold loads down the engine noticeably more than just moving the tractor would cause. (This may also be why the manual calls for a five minute warmup).
If this braking feature were out of adjustment, it could cause what you describe.
I don't really know the history of the tractor, but did call the owner just before I bought it. He definitely seemed unsure of himself and hesitated when I asked if he had ever added STP or equivalent to the tranny. Made me suspect he had, which I suppose could casue clutch pack problems, but I would suspect symptoms more along the lines of a slipping dry clutch if that was the problem.
I will look into the braking feature you are referring to. This problem doesn't go away when tranny is warm, and I really only use mid or low range, and usually low on power shifter. I probably only have 5 hours on the machine, so still figuring it out, but runs unlike any tractor I have owned or operated before.
