4320 Diff lock

tlock0331

Member
I just brought home a 4320, overall a very nice original tractor. 5200 hours, cab, ac works, needs some minor things, but overall, seems like a pretty descent tractor....

However, I noticed that when i turn, its kinda growly, like maybe the brake is barely getting pushed, pull up straight and it sounds normal and no pulling, steering works fine, but you can kinda feel it pulling in the rear.

I hit the diff lock and you can feel the difference, kicked in easy, released easy. Made a difference in how it steered, but released and started acting the same.

Any suggestions? I dont know a lot about the general operations of the diff lock, so start where people are a lot smarter than me...

kinda want to pull a split row 7000 planter this spring with it, but that growl on turns kind of concerns me.
 
I'm confused ? You should not be able to steer it with the diff. lock engaged ? It should keep going straight and slide the front wheels I'd think ?
 
Ya, I am a little confused as to what symptoms when. It
sounds like diff lock has nothing to do with the growling when
you turn.
Guys like Tim S might help. I can only offer a suggestion to
go to your JD dealer and get an oil specimen bottle, take your
sample and send it to the lab. That should tell you if you have
anything serious going on.
Paul
 
Sounds like your Spider gears are bad, in the differential,,you can look into the bung hole an the back of the case and maybe see if the shaft has been working in and out.
 
Does it quit growling,seems like it was
lightly sticking after awhile? I had that
on the 4020 that I just got done going
thru it. Thanks a bunch to TimS. Anyway
with the growling/lightly sticking I took
a chance that it might be a sticky brake.
I rebuilt the brake valve, no difference,
pulled the final drives put new
pads,orings,backup rings and cleaned the
pistons, that was the answer. May or may
not be the answer to your problem just my experience.
 
Yea, i didnt get everything on my mind out in the first post.

I wasnt turning with the diff lock on, i was trying to eliminate that by saying it locked in and out with what i thought were correct actions, and when going straight there is no noise, so it didnt seem like the brakes, but since there was no noise on a straight line, maybe the diff lock was putting some pressure on since it only made noise while turning, either left or right

Mike - it does try to slide the front wheels on turns with no brakes on and it does seem to need a light brake action to turn. i forgot to include that the first time.
Again, i am not leaning towards the brakes being the issue since there is no noise while going forward/straight.

I was hoping that maybe there was an adjustment in there somewhere, but based on the replies here, TimS and IowaJohn, i am betting on spider gears...which doesnt sound like ANY fun

So if a guy is going to get into the diff for the spider gears, is there any sort of an upgrade that could be done in there? heavier gears, or something else? if im gonna open it up i may as well try to make it better if there is a way....
 
Remove and cap the diff lock line before you tear it down,,that will prove the diff lock valve is not leaking a bit of pressure to cause a bit of drag,,Deere went from a 2 pinion set to a 4 pinion set then to a 3 pinion set, the 3 pinion set is the best,,but I would go for a good used 2 pinion one,, Mole board plowing was tuff on those back in the day,, the land wheel was always slipping a bit, since hardly no one plows like that any more a diff will last longer.
 

Thanks for the reply Tim, just out of curiosity, how many hours would a normal person expect to have into this. Not someone with your skills, but a normal dude. lol

If a guy is getting in there, are there other things that should be looked at and or planned for?
 
If you don't have a cab its not to bad. I had to replace the diff on a 4520 once doing the same as yours, I installed a 4840 diff in it. The rockshaft and both axle housings need to be removed. I left the tire on the axel when I removed them but if you don't have a way the lift it all have fun with the wedges! You will need to shim it back into specs also. I have a tech manual if you need any specs.
 
Like 4520 said it's not a bad job,,maybe 10 hours or so,, you should have a look at the transmission pump while it's out,look at the brakes, and change the left pinion bearing too,it's on the pull side so it will have more wear on it for sure,,I leave the wheels on the axles set the complete wheel,final drive off in one chunk,,if you have actsess to a couple floor cranes you can jack the wheel up and let it rest on the crane legs and use it for a dolly.
 
Check the brake pedals to see if they are both up . Sounds like the brake valve might have a stuck piston letting one brake drag . What kind of oil is in the tranny , DEER uses bearium in the oil to keep brake chatter down . just a thought .
 

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