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John Deere final drive

jimmy s

Plastic
Joined
Dec 31, 2019
Hi all, I have an elderly neighbour with a john deere 350 dozer that has had a major fail in the final drive. i've volunteered to help rebuild it and the two main jobs are to sleeve the output bearing/duo-cone seal location and to make a new pinion shaft. I've made quite a few gears before but they've all been smaller metric types and use 20 degree pressure angles. This little dozer's pinion (13T) looks to have a pitch of 3/4" and a tip diameter of 3.661" but i don't know the pressure angle and am struggling with the DP online calculators... I'm wondering if anyone has experience with these machines and can advise what cutter i should be looking to buy... thanks
 
OK, do you have exact model number? is 350, 350 c. 350 D etc, serial number is needed. not a crawler loader, a bulldozer for sure?
T24862 may be part number, need more info.
T23707 may be part number, also.
NOTE; catalog show several mating gears, all with 56 teeth, not sure what is the difference.
 
Here it is

In all seriousness, I would be getting one from a tractor junkyard. We have a significant number of these in the US and are much better solution than attempting to make a new pinion gear.

Even though the 350 is a low horsepower dozer, there is a lot to making that pinion gear and not just in the tooth profile.

There is probably a reason why you are having trouble with the tooth profile and that it is a non standard profile engineered specifically for the application. The heat treat on this is crucial. To hard and to deep, the teeth break off. Too soft and the teeth fail quickly.

What does the bull gear look like? Usually if the pinion looks like that, the bull gear will be missing at least one one or two teeth.
 
Yes it's a 350c bulldozer. In this part of the world (and with the virus causing so much havoc)its difficult and costly to get spares for these relatively rare machines, hence my offer to help him out with a rebuild. I'm sure i can help him out and it will only cost me some en 36 and case hardening, as well as purchasing a cutter.
 
In all seriousness, I would be getting one from a tractor junkyard. We have a significant number of these in the US and are much better solution than attempting to make a new pinion gear.

Even though the 350 is a low horsepower dozer, there is a lot to making that pinion gear and not just in the tooth profile.

There is probably a reason why you are having trouble with the tooth profile and that it is a non standard profile engineered specifically for the application. The heat treat on this is crucial. To hard and to deep, the teeth break off. Too soft and the teeth fail quickly.

What does the bull gear look like? Usually if the pinion looks like that, the bull gear will be missing at least one one or two teeth.

We've checked for used spares but no luck. I'll instruct the heat treatment people to aim for Rc 58/60. En 36a or better still En 39b is a good tough material for this part. The bull gear is in surprisingly good condition considering and i'm confident with some careful dressing it'll go another turn.
 
We've checked for used spares but no luck. I'll instruct the heat treatment people to aim for Rc 58/60. En 36a or better still En 39b is a good tough material for this part. The bull gear is in surprisingly good condition considering and i'm confident with some careful dressing it'll go another turn.

Your missing the point about the tooth profile being proprietary. Due to the small pinion diameter and bull gear diameter ratio. I think JD engineers used an approach that used a varying pressure angle profile to get a good tooth pattern and to get the needed torque transfer. Not saying you can't do it but you won't find the needed cutter in a catalog. Almost guarantee it that it is a custom.
 
Thanks Ziggy, I've got a pet gearcutter i can take it to and look into him cutting the same profile on the new shaft.
 
OK the T43410 Is the only option that I see. It is possible to use an complete, housing and internals for a later model, if you can verify bolt patterns are the same.
 
Yes it's a 350c bulldozer. In this part of the world (and with the virus causing so much havoc)its difficult and costly to get spares for these relatively rare machines, hence my offer to help him out with a rebuild. I'm sure i can help him out and it will only cost me some en 36 and case hardening, as well as purchasing a cutter.

You live, essentially, in the arse of the world. But you have Internet access, so you can pretty much access the rest of it.

How badly do you want to be involved in the next rebuild?

Personally, I'd start looking for a used parts dealer in the US or anywhere else that will talk to you, and swallow hard and accept the tariff that will have to be paid to get the part you need, delivered.

I don't know who or what you have access to as far as a custom cutter grinder goes, but the chances of pulling one out of a catalog are likely around zero.

If it were a shitty piece of farm equipment that was seldom used, and easy to access to repair, maybe going by guess and by golly would be a viable method, but what I see is a WHOLE lot of work getting the parts in and out, that will be down the shitter when the part you made follows the original one to it's doom.
 
If it were a shitty piece of farm equipment that was seldom used, and easy to access to repair, maybe going by guess and by golly would be a viable method, but what I see is a WHOLE lot of work getting the parts in and out, that will be down the shitter when the part you made follows the original one to it's doom.

+ 1 on what he said.
 
"You live, essentially, in the arse of the world" I had a chuckle at that... Yeah its a long plane ride down here but otherwise its paradise. I've made an enquiry with a trader in the US and we'll see what the shipping quote is. A buddy recently got quoted $500 US to airfreight a small part from michigan to NZ on account there are very few planes coming this way at the mo. once (if) the tooth profile can be reproduced the rest of the job is pretty routine and there is no reason why it wont see us out.
 
Obvious answer get it sent sea freight ....and I' d get the matching bullgear too.....Im well experienced with dozers ,final drive parts usually fail because bearings are loose....check the sprocket drive bearings and seals......No part you could make would last in a dozer....might be OK in a machinery rally type crawler tractor.
 
"No part you could make would last in a dozer" Well I'm sorry John but we are going to disagree on that, if you choose carefully which jobs you take on ...of course this machines less than 5 ton/40 odd HP.
 
"No part you could make would last in a dozer" Well I'm sorry John but we are going to disagree on that, if you choose carefully which jobs you take on ...of course this machines less than 5 ton/40 odd HP.

What part of "forged" are you not understanding ?

yes it's low HP, but the shaft is sized for only that HP, and a not even low enough
for the severe service it see's as the frequency of repairs in that area are many.
 








 
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