350b Reverser shot?

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Jetboatjay
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350b Reverser shot?

Post by Jetboatjay » Wed Apr 07, 2021 6:36 pm

Hello folks, unfortunately my first post is because I’m looking for help. I’m sure this question has been asked before but I wasn’t able to find a similar post.

I have a 1974 350b I bought from a friend who has owned it for about 40 years. So far I’ve only put about 20 hours on it, and now when I engage the reverser in either direction absolutely nothing happens. No change in rpm, no noise, the pto shaft does not change direction. Nothing.

So what happened was I was trying to break up some frost and push it into a pile. I had stalled it a couple of times when I hit the solid frost but no big deal just fire it up again and carry on. It was working fine and the reverser was happily shifting forward and back as it should.

So I stalled it pretty hard one last time, it went from 2000 rpm to not running in a matter of probably 1-1/2 seconds. No weird noise, no chatter, no snapping sound, nothing out of the ordinary, but when I fired it up again the reverser seemed to not be working any more. Absolutely nothing happens when I shift it. Is there anything I can check for before pulling the engine and reverser out?

Now I did check the dipstick in the reverser and it was dry. It took about 3 quarts of fluid to put it in range on the dipstick. It still won’t move though. I have a hard time believing it failed because of low fluid level, as it was working perfectly right up until it decided to quit. Didn’t slip on me once.

Thanks in advance for any advise

Jay

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Lavoy
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Re: 350b Reverser shot?

Post by Lavoy » Thu Apr 08, 2021 8:01 am

My guess would be the isolator failed, but no way to verify without pulling the engine.
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Jetboatjay
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Re: 350b Reverser shot?

Post by Jetboatjay » Thu Apr 08, 2021 11:41 am

Lavoy wrote:
Thu Apr 08, 2021 8:01 am
My guess would be the isolator failed, but no way to verify without pulling the engine.
Lavoy
Hi Lavoy thanks for your response.
I was definitely leaning that way, but here is something strange. The winch drive has always “freewheeled” counter clockwise at a low rpm when the engine was running and reverser in neutral, and run at a higher rpm with the reverser locked in forward, then obviously it changed direction with reverser in reverse.
So now after “the incident” the winch drive is still free wheeling counter clockwise when I run the engine but is unaffected by switching gears in the reverser. How would the winch drive be turning at all if the isolator has failed and is not turning the main shaft in the reverser?

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Re: 350b Reverser shot?

Post by Jetboatjay » Thu Apr 08, 2021 11:44 am

Another point to make is, if the isolator has failed from the large amount of resistance when I ran into that frost layer, wouldn’t the motor have continued to run instead of completely stalling?

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Re: 350b Reverser shot?

Post by LeonardL » Thu Apr 08, 2021 3:04 pm

Your isolator would cause more issue if it was to fail. As in usually they lock the motor up by wedging a piece of something in between the flywheel and the bell housing. If they don't lock up then they will literally sound like an old hammer mill rock crusher!!

I would pull the floor boards to see if you have a shifter linkage come off or something simple before I would go to all the trouble of pulling the motor and reverser. If it was indeed low on fluid then I would suspect a number of things and all of them require pulling the reverser. You say your PTO is still turning so it sounds like you are still connected to the transmission. Put a block of wood against it to see if it is still under power or if it is just free wheeling. If you can stop it then you have a connection issue somewhere.

There is a splined coupler that connects the reverser to the transmission and those are bad to strip out and cause your issue. Especially on these older machines. If your reverser is still working then it should be making some noise even if it isn't connected to the transmission. You can pull the top off of the transmission to see if the power is being transferred through to it. This could also be stripped steering clutches although I doubt it. Unfortunately you may have to just dig into it to find the issue.
40 plus years working on JD 350s, 400Gs, 450s and other equipment both Ag and Construction.

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Re: 350b Reverser shot?

Post by Jetboatjay » Thu Apr 08, 2021 8:20 pm

Thanks Leonard.
Yes I can stop the pto winch shaft by hand. Shifting the reverser in either direction doesn’t affect it either way it just keeps free wheeling and I can still stop it. It is acting just like it did with the engine running and the reverser in nuetral before it quit working.
There is zero noise coming from anywhere in the drive line when I shift it. It’s just acting like the shifter isn’t working

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Re: 350b Reverser shot?

Post by LeonardL » Fri Apr 09, 2021 9:29 am

Okay so before I get completely stupid here... does your PTO have the shift lever down by your left foot that will engage / disengage the PTO? Some have the shift option and others were driven directly. I just want to make sure which way yours is configured.Obviously if the PTO is disengaged then it will free wheel just like you describe. If it shifts then make sure it is engaged to check transmission connection or engagement.

That being said, my next question is based on what you say you're "Not" hearing. So can you still hear the distinctive 350 rattle when the engine is running? 350's with a reverser have a given distinctive noise they make especially when the engine is idling. This noise or rattle is caused by the Isolator and the counter shaft inside the reverser. Your 350B will most likely have the five spring with center hub isolator. 350D's have a one piece rubber isolator but they still have the rattle coming from the counter shaft. When you shift the reverser you should also hear the distinctive high pitched whine that the 350 reverser is famous for. I'm just trying to get a little more idea of what you're hearing / not hearing.

You may have slaughtered the isolator but in my experience there has always been an even worse noise coming from the bell housing area or they lock the engine up. That does not mean it isn't broken. Anything is possible with a 350. If I have learned anything over the last fifty plus years is that a 350 will do exactly what you don't think is possible!

You may have sheared the input shaft leading into the reverser or may have stripped the splines in the reverser pump but you should still have the isolator noise. My point is, 350's don't just go quiet. They don't have quiet bone in their bodies.

Start simple and work out from there. Check linkage all the way through the valve body and foot clutch. If all of that is oaky and functioning then you will have to go deeper. If you don't have a tech manual then get one. Parts book can help identify parts but they don't always reflect what the tech manual identifies.
40 plus years working on JD 350s, 400Gs, 450s and other equipment both Ag and Construction.

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Re: 350b Reverser shot?

Post by Jetboatjay » Fri Apr 09, 2021 10:33 am

Hi Leonard
My machine has a direct drive pto. No lever on the floor

It sounds just like it always did at idle, and when I shift to reverse with the reverser lever it does not make the “reverse whine”. Absolutely nothing happens.

I do have the tech manual so I have a basic understanding of how the drivetrain works, but I have never worked on one

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Re: 350b Reverser shot?

Post by Stan Disbrow » Sat Apr 10, 2021 4:45 am

Hi,

I am thinking the reverser oil pump has a problem. It sounds like it can't make up the reverser clutch pack. Both forward and reverse need oil pressure. And it was said to have been low on oil.

There can be enough friction in the clutch pack to allow the winch shaft to turn slowly when in neutral. And that would mean the isolator is still attached. Especially as they sound like all the dwarves in Tolkein are mining inside the bell housing when they go....

Stan
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LeonardL
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Re: 350b Reverser shot?

Post by LeonardL » Sat Apr 10, 2021 8:25 am

So have you checked your shift linkage? Also while it is running and with the reverser shifted into either forward or reverse, work the clutch pedal a few times and see if it changes anything. That is if you haven't already. Check your reverser pressures with a gauge and see if you are getting any pressure through to the valve body. If you have pressure within specs then it will have to be something else. If no pressure is detected then I would check the valve body itself by pulling the end plate off to make sure your accumulator spring isn't broken or some part of the mechanism isn't functioning as it should. If the accumulator is stuck in the off position then it will dump pressure directly and you won't have anything. Some of the guys on here have had the shifting pawl on the inside of the valve body either come loose or is worn out and not shifting the reverser into gear. My point is, check the simpler, easier to get to stuff first. None of this is easy, believe me. But it is easier than pulling the reverser. Do the process of elimination. Follow the flow of how this works and rule out things as you go.

I would also check the filter to make sure it hasn't collapsed and gotten sucked into the pumps inlet side or the sump port. By you working the machine hard you may have jarred it enough to cause an issue with the filter. Otherwise... I hate to be the downer here but it sounds like you will need to dig deeper to find it.

If you do then start by pulling the motor to check the isolator and work in from there. You can check the input shaft and reverser pump without pulling the reverser. I'm not sure what you will find because it could be any number of things.

The reverser pump is a tough little bugger and I have only ever seen one that stripped the splines that drives them. I've seen them be pretty much destroyed and still try to pump fluid. I have seen more input shafts snapped in two than I have anything else. However that being said the pump drive splines can and will strip out. Lets hope you can find a simple solution to this and get back to work.
40 plus years working on JD 350s, 400Gs, 450s and other equipment both Ag and Construction.

Jetboatjay
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Re: 350b Reverser shot?

Post by Jetboatjay » Sat Apr 10, 2021 9:12 am

Thanks for the advice fellas. Right now I am using a rented cat 320 hoe and a small wheel loader to clear and level my property but the owner wants them back soon, so I’ve been frantically doing as much work on them as I can. So I haven’t had any free time to look at my crawler yet it’s just sitting off to the side out of the way.
I’ll definitely let everyone know what I found.

One question though how low can you let these units run on oil, and what would be the first thing to fail when it’s perilously low?

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Re: 350b Reverser shot?

Post by LeonardL » Sat Apr 10, 2021 2:29 pm

Your reverser holds about three gallons. Give or take a little. The issue of being "Perilously" low is hard to determine given it depends on what you're doing and what sort of terrain you're on. To me as the mechanic I want you the operator to keep your fluid levels up where they belong. Which would be within the operating range at the very least. Preferably right on the full mark. So anything below the bottom of the operating range would be too low for me to be comfortable. The fact you said the reverser was dry but yet it only took three quarts to bring it back to the operating range seems a little off to me. I'm not saying you were wrong. I am saying that three quarts low from the full mark is still leaving you with over two gallons of fluid. Which in theory should be enough to run a 350 reverser.
40 plus years working on JD 350s, 400Gs, 450s and other equipment both Ag and Construction.

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Re: 350b Reverser shot?

Post by Jetboatjay » Sun Apr 11, 2021 8:29 am

The reverser wasn’t dry, the dipstick was dry, and 3 quarts put it back in operating range

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Re: 350b Reverser shot?

Post by Jetboatjay » Sun Apr 11, 2021 8:34 am

I personally don’t think it failed because of low fluid. I had been working it on pretty steep angles earlier in the day pushing sand down a pretty steep bank running uphill and downhill both directions and it worked flawlessly right up to when I stalled it, which was on flat ground

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Re: 350b Reverser shot?

Post by Jetboatjay » Tue Apr 20, 2021 1:08 pm

Ok so I finally had time to look at this crawler today. I found that with the floorboards out all the linkage seems to be shifting smoothly. I checked the oil regulator valve pressure and found in the neutral position I have zero pressure, and if I shift it into either forward or reverse it slooooowly builds pressure up to about 22lbs and holds there. This takes about a minute. Obviously that is way low. Adjusting engine rpm has no affect on the pressure.
I haven’t checked the pressures in the cooler regulator valve or the lube regulating valve yet, since I obviously have a problem already

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