clutch not working properly

I'm away from my 'puter right now so I don't have access to the specific oil info, but it was a AGMA rated 20w machine oil. I'll get specifics when I get back.

You will have to tap into the clutch hydraulic system to see what pressure you're getting. It should be between 30# and 50#. This pressure overcomes the spring engaging pressure of the planetary drive servos (there are two, one forward – one reverse). There is also a possibility that the accumulator has lost it's charge for some reason.

It sounds like one or both of your servos is not releasing the spring pressure. These work very similar to the steering clutches.

Do you have the parts and owners manuals? If not I can send them to you.

The specific oil for optimum performance is ISO AW 150 machine oil.

This is available in almost all popular oil brands.

I forgot to ask if you had checked and cleaned the suction strainer in the bottom of the case.

Shop tip if you didn't already know: It's easy to tap into a hydraulic system anywhere there is a banjo bolt used. Simply drill and tap for 1/8″ NPT in the center of the hex head. Install a high pressure needle valve and a 3,000 PSI gauge. When you are done testing, install a 1/8″ NPT steel pipe plug.

I'll check and get back to you asap.

Closest match to spec is Shell Tellus 32 (preferred) or Tellus 25. Rotella is engine oil – not recommended in this application, I don't care what the dealers say.

Note: You won't need a 5,000 PSI gauge to test the clutch hydraulic system, a 200 PSI gauge will do.

There is a reason for the specific oil recommendation. Why can't your supplier get Tellus 32? Where are you purchasing the oil?

As I asked before, does your left saddlebag reservoir have a sight glass? This is where oil is stored for the shuttle clutch. This reservoir holds about seven gallons.

A picture of your left saddlebag (battery) compartment would be helpful.

180° to 200° is at the maximum upper limit. Should be around 160° to 170°.

Then how is your accumulator plumbed? Do you have a reservoir on the left side? That's one of the reason your oil temp is so high, the oil doesn't spend enough time in residence to settle out, cool, and deareate.

You have to shrink pictures to around 350MB then click the tree icon and navigate from there. If you get that far me or someone else can walk you through from there

I have a plumbing schematic I will post when I get home.

Do you have an outlet at the rear inside at the bottom of the unused reservoir?

This is what your left saddlebag should look like. Somewhat.

?

How about a big one on the seat side? Should look like the same one in the right saddlebag for the tractor hydraulics.

Your plumbing system should look like this:

Did you make sure the reservoir was meticulously clean before you added any oil?

Do you still have the tee'd line going to the accumulator from the pump discharge?

At this point where is the oil level on the dipstick?

Do you have provisions for a sight gauge on the reservoir? It would be a steel boss with two 17mm bolts about 3″ apart.

Hi guys–I'd just like to jump in here and say that I have all the exact same issues with my yct 306s crawler.I recently changed all the oil with the recommended grades—shell rimula 40wt for transfer case,  10wt hydraulic,  30 wt  engine.   But there are 2 fill holes on floorboard–front one for clutch case, rear one for transfer case,  and only the right side hydraulic tank is in use.  It will run and shift normally for about 5 mins,  and then will abruptly stop with NO neutral to be found.  I can wait 10 mins, start up and it will be okay briefly.  I am about ready to suck it up and pay someone to get it fixed, but can't find anyone willing to work on these Chinese machines.   Does anyone know of  mechanic in the Medford, Or. area who will??            thanks,  Jeff          

What is the “transfer case”? Do you mean the transmission and bevel gear compartment? If so, that's supposed to have 80W-90 gear oil in it, and 85W-140 gear oil in the final drives (one each side). And I'll wager that neither of you gentlemen are running the correct oil in your shuttle clutches. On the bottom side of the shuttle clutch there is a bolted flange that contains a strainer. This strainer must be cleaned periodically.

Who uses 30W oil in these engines? What is the API rating of that 30W oil? 

Hi Bob–Jeff here………….On the floor board, there are 2 fill holes; the one in front of shifter is labeled clutch case, and the rear one, gearbox.   Not to be confused with final drive-one on each side.  Under oil recommendation, it says-engine sump=30w high ash rimula,  transfer case/transmission box=40w high ash rimula,  hydraulic sump=iso 32//sae10…………nothing about shuttle clutch.    AND,  my left tank is not being used!    In that compartment–battery side- there is a cylinder(accumulater??) with one line going to it from rotator valve.  when I removed it,  a small amount of dirty oil came out(all the oil sumps are full of see-thru clean oil)  What is the function of this spring loaded cylinder?    I'm fairly certain the importer I purchased from had never set up a crawler before,  and he is no longer in biz.     Will I have to drain oil to check/clean strainer?       As a licensed denturist,  I spend more time grinding on teeth than gears.   I can handle the mechanical part,  I'm just a little short on the functional knowledge of this beast.   I have the feeling I'm gonna  get to know it better in time……and thanks for your time and patience………. ,    Jeff,  Gold Hill,  Oregon………

Hi Jeff,

Yes, I'm familiar with the OEM lubricant recommendations, however there is a lot lost in the translations. The shuttle clutch should be using ISO AW 220 machine oil. This oil is recommended for geared friction drives and has an AGMA grade rating of 5. Any brand can be used as long as it meets those specs. In my opinion this is the best selection for this type of drive that uses planetary gearing and friction clutches. You can also use Caterpillar TO-4 if you have a lot of disposable income.  There have been other owners that say shuttle clutch performance was greatly improved after switching. The clutch also runs cooler.

Yes, that is a hydraulic accumulator in the left saddlebag. That acts as a cushion and also stores pressure (about 40 psig). The clutch packs are engaged by spring force (kind of counterintuitive) and disengaged by servos using hydraulic pressure. The clutch oil must be drained in order to clean the strainer. This system should be impeccably clean.

What they are calling the “transfer case” is actually the bevel gear case which has a common sump with the transmission. This is a high gear tooth loading arrangement and requires an EP lubricant, hence the 85W-90 gear oil.

Did you know there is a dealer for these dozers in Oregon? KENO Tractor in Keno, OR.

Hi Bob and thanks for your time– Are you familiar with Shells top of the line transmission oil SPIRAX GL-4?  and could it be used in trans case or clutch tank.?  I think you recommended aw 220 machine for the clutch,  and 85-90 w for the transfer case(not the final drive).   And should I plumb the empty tank, lft side for the shuttle clutch oil??   research shows quite a variety of the 220 oil(sewing machine)–around $70-100 per 5 gals…….I think this is enough for me to take on for now!!   thanks,  Jeff     

The Spirax S3-G is a good oil for the transmission and “transfer case” in the appropriate weight. Don't even think of using it for the clutch – way too heavy.

Not sure where you get “sewing machine” oil, but here is a guide you can use to find substitute oil. And yes, that price is about right. Please bear in mind that I'm making recommendations based on my education as an engineer and many years of experience in the field, but you are under no obligation to follow them. 

http://www.duboischemicals.com…..0Guide.pdf