350C Power Issues

[Jason37756]

I’ve got a 350c that spins the tracks in 1st gear but won’t move more than 3 feet when placed into 2nd gear. The crawler moves better in 3rd & 4th but has no pushing power. I have the same results in forward or reverse.

What’s your thoughts on where the problem is?

I’m no expert with the wet clutch machines and have read so much that I can’t wrap my mind around what is going on inside the reverser as it relates to the transmission. I have the tech manual.

I don’t hear any abnormal noise or feel anything grinding.

New fluid and filter in the reverser. I am unable to check the pressure on the valve due to the plugs being wallowed out…the shift rate from forward to reverse is good.

Thanks

[LeonardL]

Sorry I didn't see your post on the wallowed out test port plugs. Unfortunately that is exactly where you need to start. Your issue could be one of a few different things or a combination of different component issues.

I have used heat to help get those plugs out. Then I replace them with a pipe plug that has the square head on it instead of the inverted Allen socket that comes from the factory.

Unfortunately you may need to drill these out and hope that you don't leave shavings inside the valve body after you're done. I have actually started the machine once I have the plugs out and let it flush oil out through the ports to flush anything out that may have gotten inside.

Your only other alternative is to pull the reverser and then break the valve body down so that you can get to the individual plugs better. I know it's deep but that may be your best bet.

I doubt your issue is transmission related. Usually on a 350 with a reverser the only thing that goes bad will be the spines on the input shaft. If it was that then you loose all power because the reverser and transmission are no longer connected.

You really need to know what your reverser is doing before you can proceed to another component. Sorry to be the bearer of bad news but that is what you need to do. Check the pressures, especially the engagement pressure and it should be a minimum of 125 PSI. Preferably on a 350C it should be up around 150 PSI.

[Jason37756]

Thanks for the reply.

I’ve already disassembled back to the transmission and repaired the plugs as you mentioned…I had a little problem with one of them on the repair so I’m gonna try to never unthread from the valve again by installing a short piece of pipe. We’ll see if I have enough clearance to leave it.

I am a bit confused with spinning the tracks in first gear and barely moving in second gear. Is it because the transmission is asking for more speed and the reverser simply can’t supply it?

I’m not a big fan of putting this thing back together for a test run. I would prefer to just rebuild the reverser if that’s where my issue rest at. I read where someone used a motor or drill to power the reverser for test purposes…I may try that before I reassemble anything.

I broke a oil tube in the process, so I’ll be needing one of those if anybody has one…My John Deere dealer says they can’t get it because it an obsolete item…I may have to machine one.

[LeonardL]

I have had these do what you're describing and in most of the cases it was a leaking seal in one or the other of the clutch packs. I have also seen the steel sealing rings on the manifold leak and cause your issue. And yes, they will sometimes go ahead and spin the tracks in first gear but not in any of the other gears. First gear of course requires less energy so the machine will still function in that gear.

So the line you broke?? Is it an oil line or one of the tubes that goes between the valve body and the manifold? If it is one of those tubes then you can find those select used at machine salvage yards. If it is one of the lines on the outside then you can replace those by either getting them used or I have replaced them with a good grade of hydraulic hose and the right fittings.

Your idea for the stand pipe is a good one by the way. If you run into clearance issues then try a pipe cap for the pipe. Then when you need to check pressures you can put your coupler on it to connect your gauge.

Personally... I would go ahead and rebuild that reverser while you have it out. Mostly because it is such a long way into them once you install it.

You can check your pressures while out of the machine. I have used a large gear reduction drill that will spin them fast enough to get pretty close to what your idling pressure would be while on the machine.

I would be careful if you hook an electric motor to check pressures. Just make sure the rated rpm of the motor is similar to what the engine would be. But then you are probably smarter than I am and know exactly what to do. I've just never tried hooking a motor up to one of these reversers. I know there are a couple of guys on here who have done this with great results.

You can also bench test the clutch packs by using compressed air. Just be mindful of where you apply your air. I always use the tubes that fit into the manifold. One is forward and the other is reverse.

[Jason37756]

Thanks for the reply…really good info.

So the oil tube that connects the valve body and the manifold is what I broke. I’ll have to figure that out. We really don’t have any good bones yards around here for these dozers.

Sounds like a reverser rebuild is in order…I’m not sure what the steel sealing rings on the manifold are but I’ll take a look at the parts catalog and go from there.

We’ll see how the bench testing goes. Might just hook the ol’ 3-179 to the reverser and see what happens if my drill doesn’t do it.

[Jason37756]

Here’s a sealing ring #30 in the accumulator. Would that be the steal ring you’re speaking of?

Thanks

[LeonardL]

No... there are two sealing rings on the manifold itself. Look in the parts breakdown for the reverser assembly and you will see the manifold and then a steel ring on either side. One for forward and the other is reverse.

Now that being said... the ring you referred to can cause issues with slippage. So you will need to take a look at it for sure. Usually however if it is a broken accumulator ring then it will slip in all four gears.

As for salvage yards, we have a good one here in Missouri. ( Zimmerman Tractor 573-378-7210 ) They will ship to just about anywhere I think. There is also out in New Hampshire, ( PB & H Equipment Parts 1-888-588-3005 or 603-588-3005 ) They will also ship all over.

You might even check with Lavoy who owns this site and see what he can do for you. He sells a lot of parts although a lot of what he does is older stuff. Still I would check with him. He's also a wealth of information as well.

[Jason37756]

Leonard,

Thanks for taking your time to reply with your wisdom.

I looked thru the parts catalog last night and saw those sealing rings after I had posted.

I’ll follow up after I start the repair work. Thanks again!

[Jason37756]

Alright I was able to get a few parts in and test the pressure in the valve body.

After doing the checks and adjustments outlined in the TM the best pressures I could get are listed. I had to add a few pennies in the two valves and adjusted the restriction orifice out five turns. The crawler moves and turns good but can’t push any dirt or spin the tracks.

Clutch oil regulating valve at 2650 RPM
130 psi with shifter in neutral
20 psi when placed in forward or reverse
“Clutch” pedal dumps pressure to zero when pushed and re pressurizes to 130 psi when released.

Lube regulating valve at 2650 RPM
19 PSI when shifted between forward and reverse.

I replaced the clutch valve lever in the accumulator housing due to excess wear on one side. Against my better judgment I did not rebuild the reverser…I was hoping the thorough cleaning and valve lever would solve the problem. Also didn’t want to risk a poor reverser rebuild on a chance without even checking the pressures.

What’s your thoughts? Still leaning toward leaking seal rings?

No... there are two sealing rings on the manifold itself. Look in the parts breakdown for the reverser assembly and you will see the manifold and then a steel ring on either side. One for forward and the other is reverse.

Now that being said... the ring you referred to can cause issues with slippage. So you will need to take a look at it for sure. Usually however if it is a broken accumulator ring then it will slip in all four gears.

As for salvage yards, we have a good one here in Missouri. ( Zimmerman Tractor 573-378-7210 ) They will ship to just about anywhere I think. There is also out in New Hampshire, ( PB & H Equipment Parts 1-888-588-3005 or 603-588-3005 ) They will also ship all over.

You might even check with Lavoy who owns this site and see what he can do for you. He sells a lot of parts although a lot of what he does is older stuff. Still I would check with him. He's also a wealth of information as well.

[LeonardL]

Yes... I think you have a seal or a combination of seals that are leaking past. You could also have disc and plate wear that could causing this. But your pressures seem out of where they should be.

Your clutch will dump the pressure when depressed. That's basically all it does. It is basically an on / off valve with an accumulator to give it a cushion.

I need to get my book out and refresh my memory on these pressures as well. It has been a while since I was last inside one of these and I don't want to steer you wrong. But it does seem like you have something not right in the reverser.

It could be steering clutches causing it not to spin the tracks but usually it isn't both sides at the same time. It will be one side or the other but rarely both. You can isolate them by plugging the pressure line that goes to the steering valve. Then check your pressures at the reverser to see if they change any. If they jump dramatically then it could be a steering clutch issue.

Now... with that being said and before I get corrected by someone... Usually if this is the case then you will have an issue with fluid transfer. That being from the reverser going inside the transmission / steering clutch housings.

[Jason37756]

Ok, I’ll plug and check the line(s) going to the steering valve and see what I find.

Before I worked on the crawler I was able to spin the tracks in first gear, now I can’t do that. All the pressures seem fine except the 20 pounds I’m getting when placed in forward or reverse.

I’ve not ran the crawler much so I haven’t noticed any fluid transfer, but do have a leak coming from the input shaft on the transmission. I noticed it when I had the reverser out and also have fluid dripping from between the transmission and reverser housing. I don’t remember over filling the transmission, but could have.