Bob Rooks

Hmm, my engine doesn’t have such a removable plate, but good for you, that’s going to be a challenge working around that equalizer bar unless you drop it, and if you do, make sure you have the tractor blocked securely.
As far as the fuel blockage goes, what did it look like? Sludge? If so, you have a case of diesel bugs and you will need to drain and clean the fuel tank and system thoroughly and treat at least four subsequent fuelings with a biocide ASAP because they are corrosive and can damage the injectors and fuel injection pump. I have personally witnessed the bugs bring a 10,000 HP diesel to it’s knees, and the subsequent $22,000 in repairs.

Daniel Halling wrote:

I’m not completely convinced that the shuttle clutch is the problem, but it wont turn. Internally the engine shaft is spinning but assembly will not turn. It wiggles left and right a little and you can see the whole shaft wiggling all the way back to the pto box. What ever happened is in the area of the shuttle clutch. Cant see problem with my inspection camera. Any idea how assembly could be stuck. The engine shaft spins freely inside the assembly. before I took apart I ran engine and engaged the forward and reverse lever, the engine would bog and almost stall and smoke came out of shuttle clutch dip stick hole.

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Not turning would be a steering clutch/brake issue, but that could be masked by a power input issue from the shuttle clutch. There have been instances in older machines where the splined input shaft to the shuttle clutch was not long enough for total engagement, and sheared the splines off. This could be the problem. I didn’t look specifically for that shaft, but it could be here:
https://www.circlegtractorparts.com/parts/?find=yuchai-bulldozer-all-yuchai-bulldozers-all-yuchai-bulldozers-6769
If not, perhaps Northern Tool.
Yeah, smoke is not good. This whole system will have to be flushed, and the directional control valve disassembled and cleaned. Hopefully the clutch packs haven’t been smoked.

Gary Griffiths wrote:

What was your oil pressure before the engine shut down? Oil pressure was showing about 3-4 on the meter. Starts at 5 when full, with cold engine, lowers to ~4 when the engine warms up. Decreases as I run engine. Usually lasts about 4 hours ’till it hits 2 and I stop and add oil. Takes about 1 1/2 qts at that time. Your gauge reads in bar if I remember correctly, so 5 bar = 72.5 psig, and 2 bar = 29 psig. All perfectly acceptable.

What kind of oil do you use in the engine? 15W40. I used Delo 400 initially, but have been using the cheap Tractor Supply oil since it started gargling with it. No problem there as long as long as it remains a multi-vis oil.

How many hours on the engine? 380 hours on the engine. Not many at all.

I have been advised by the diesel mechanic I talked with that if it sat for a long time (which it did) without running, the valves may have been damaged, and oil is entering the cylinders. This is misinformation, but he may have meant stuck valves (which is a very remote possibility) Otherwise, may be rings. This is very likely. There has been some smoke coming from the oil fill cap, but have been advised that may be normal as it serves as a vent for the crank case. Depending on the year of build, your engine may or may not have a PCV system. This consists of a hose between the valve cover and intake manifold. There is an orifice in the intake manifold hose connection. If you don’t have this feature some vapors from the breather may be present, but not a lot. That symptom, coupled with high oil consumption, do point to stuck or broken piston rings. You can perform a compression check to verify this. I don’t know what your resources or skill levels are for performing engine work, but I recommend pulling the cylinder head to check for cylinder liner wear/scoring. We can go from there.
From what you have told me, your engine seems otherwise healthy.

Well, your implement dealer is very ignorant. Parts are plentiful online.
What was your oil pressure before the engine shut down? What kind of oil do you use in the engine? How many hours on the engine?
It sounds to me like there is a fuel restriction. These tractors do not have an in-tank filter. First, observe the contents of the sediment bowl, then shut off the fuel and remove the sediment bowl and check the screen in the top. Let us know what you find.
I know it seems like I ask a lot of questions, but they are essential for an armchair diagnosis.
:yes:

All good advice from Piper. I would also ask if you topped off your fuel tank before you laid it up because condensation can build up and then it’s a breeding ground for diesel bugs. One thing that can happen to diesel fuel in cold weather is that it can gell. This is where the “wax” in the fuel becomes solidified and won’t let it flow. It can also plug the filters. There are anti-gell additives available to add to your fuel. Unfortunately, once the wax has solidified heating the fuel will not make it miscible again. However, keeping the fuel warm(er) will prevent this problem.
Please keep us posted.