350B Reverser Input Spline

[pernsdorff]

Well, here is my first technical post as I dig into my crawler.
The machine starts great but it is obvious that it has been missing some needed TLC. So before I start putting the machine to some serious work I am going through it. I noticed that it has been run with both the steering fluid empty as well as no fluid on dipstick of reverser - likely damage reverser?

Right now I am tearing apart and cleaning off the years of debris and gunk. First step, off comes the engine.

So, 2 questions here, first off note the worn splines on this image. Is this an immediate concern or do I just run it until I lose all power because of it? Second, how loose are the springs supposed to be on the isolator.



Thanks for any helpful tips as the fun begins.

[jdemaris]

In regard to the splines - considering the cost of new one - I'd use it as-is. Just put some special grease on the splines designed to prevent future shock-wear. Most companies e.g. I.H. and Deere recommend using a molybdenum disulfide grease on splines to prevent them from hammering out. What about the other splines behind the reverser??

In regard to the springs - there's no room for allowing any wear. Same goes for the posts where they attach to the flywheel, the anchor clips, the pin-stops driven into the flywheel, and posts and splines on the isolator-drive-plate, etc. In addition, you need to make sure the openings of the spring-hooks face in the proper direction when installing. That type of isolator is a miserable setup and was the #1 failure problem with 350Bs on through the C series - and then Deere fixed it with an updated system.
You can install the newer system on your's - but it's expensive and requires a new flywheel. The first 350s used a conventional spring-loaded clutch disc - just like the 1010s and it worked fine. But late 350s on to the Bs used that awful isolator setup like you have. If anyone tells you it's "not a big deal" to fix - they don't know what they're talking about. At one time, we had a run of brand new 350Cs siezing up from isolators falling apart before they even got sold.

In my opinion - if you're pulling the engine out anyway - you ought to pull the reverser out and go through it unless you have reason to believe it's absolutley perfect. Get yourself a dial-indicator and check end-play on the reverser input-shaft. It should be .002" to .005". If a lot more, pull it apart. Do NOT try to check it by "feel" since the shaft will jiggle no matter how tight or how loose it is adjusted. Many "rebuilt" reversers fail almost immediately because the mechanics thought they could adjust by "feel" like a wheel bearing. It does NOT work. I probably rebuilt at least one reverser a week for many years and have seen what happens when people take shortcuts.

[pernsdorff]

I didn't check pressures yet on the reverser before pulling engine. End play "feels" tight. I will get a guage to confirm. The reverser seems to operate but it was finicky when it would decide to move. But that was before I realized the low fluid level and figure that was why.
Isolator is an odd looking setup. The springs seem quite loose. That plate can be moved about a fair amount -- almost an inch of twist by hand. One of the main reasons I went ahead a pulled the enghine was because the rattling noise it made whenever I shutdown the engine just didn't seem normal -- this seems to be where the noise is from.
Does this play sound exsessive? I assume the fix for this is new springs?

[jdemaris]

Isolator is an odd looking setup. The springs seem quite loose. That plate can be moved about a fair amount -- almost an inch of twist by hand.

Does this play sound exsessive? I assume the fix for this is new springs?

They are rattle-traps even when all the parts are new. Judging by your spline wear - I'm going to assume your isolator parts are worn. Look closely. The anchor posts that the springs attach too - on the flywheel and also on the center-plate are usually worn. The angles clips that bolt to the flywheel are usually worn. The stop-pins that are driven into the flywheel are usually hammered, bent, and/or broken. The center-plate usually has the brake-lining material ripped off it (it's supposed to have a facing on it where it contacts the flywheel. And, how are the splines in it where the input shaft goes into it? And, then there's the springs. They are just about always out of spec - but check your Deere tech manual - it will give you proper specs as to length. Look at the end-hooks for wear.

Keep in mind that when we were fixing them - these crawlers were being used daily - all day, every day. They weren't part-time collector's items.

I've probably fixed hundreds of isolators -and usually all parts get replaced when durability is an issue. You also have to use a lot of Loctite when assembling or it will fall apart. All that needs to happen is one of the angled-clips to twist a little and it will contact the clutch/transmission housing and all will fall apart.

The best way to go - IF all the parts are highly worn - and you really plan on using the crawler hard - is to upgrade to the newer setup. It doesn't cost much more and will never come apart.

If it's just a part-time user - then just patch it up best as you can. Maybe new springs if your's are stretched and lots of Loctite. If the front shaft if fairly tight - pull the front pump and check it for wear, install a new front seal - and leave the rest alone and take your chances.

In regard to the reverser - the #1 failure point is the center-bearing inside the reverser. It was too small in the early machines - but got upgraded to a larger bearing with the "B" series. So, hopefully, you've got the bigger one. When it gets worn, the front input shaft will show excessive end-play. That because they are all in one line - the front input shaft bearing, then the center bearing between the input and output shaft, and the the bearing at the end of the output shaft. Since they are all in one line, and if any one of them wears - the entire assembly gets loose. Since the centerbearing is smaller then the rest - it is the first to wear. It only turns when the reverser is used in reverse. That is why reverse is weaker than forward.

[gene s]

I had a similar looking input shaft, only worse. The splines were more than half worn down. Since I upgraded to the new flywheel and isolator setup I also decided to replace the shaft. I use my machine fairly regularly and already have a large amt. of cash spent on the isolator upgrade. Besides that, I have my good friend who is an equipment mechanic for a large excavating contractor here in north central ill. helping me and he told me I would be a f****** fool if I didn't fix it rite. The part isn't cheap by any means, but with all the repairs I've done to this machine over the last say 5 years rite now it's worth it.

[Tigerhaze]

Hi Gene-

JDEMaris has posted the parts numbers and costs previously for replacement of the flywheel and isolator; I have attached the link to that thread to save some typing in case you are interested:

http://www.jdcrawlers.com/messageboard/ ... php?t=2823