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Help me diagnose my D6c final drive

D6c10K

Senior Member
Joined
Apr 1, 2008
Messages
681
Location
Iowa, USA
About two years ago I had the LH final drive worked on. Bored out and put a bushing in to get the dead axle back to spec when it's pressed in. At the same time I put on new chains, sprockets and rollers.
Not long after I noticed a clunk in the undercarriage I hadn't noticed before on the left side. I kind of chalked it up to new undercarriage being different.
Didn't use the dozer much the next year, but used it quite a bit last summer cleaning out a pond and pushing out fence and a lot of trees.
I began to notice a clunk again in the LF final drive, and found that it only happens when backing up a slope and shifting to forward. It's a pretty good clunk but if I idle it down more and come to a complete stop before shifting to forward, it doesn't do it. Doesn't seem to do it at all shifting from forward to reverse.

I dropped the oil (80-90W GL5) out of the final and found some steel fuzz and some small flakes but no big pieces. The odd thing is the oil also had quite a few brass flakes and the oil had a very pronounce brass color. As far as I know there are no brass components in the final drive so I don't know where it could possibly be coming from.
I don't think its a seal problem between the bevel gear case and the final because I don't lose trans oil and the final drives don't get over full. (the finals don't leak either)

I also dropped the oil out of the other final drive and it just had a small amount of steel fuzz on the magnetic drain plug. There might have been a tiny amount of brass color in the oil but not enough to notice if you weren't looking for it.
One guy I spoke to said he had seen some final drive pinon bearings that had brass bearing cages but that's the only possibility we could come up with.

I also backed off the brake band on the LH side, pulled out the access plug on the side of the bevel gear case, and used a pry bar against the clutch drum to see if I could detect any movement from a loose bearing, but couldn't see any.
I suppose it's possible the bearings on the second reduction gear could be loose but there's no way to see it.

Anyone seen this before? Do I put in new oil and watch it to see if it gets more brass/steel accumulation?....or is it about to grenade on me?

Here's most of the steel I could fish out of the oil with a magnet and off the drain plug. Funny thing is it looks like some of the brass is picking up on the magnet, but I suppose it could have some steel imbedded in it from going through gears.
Magnet.jpg

The next three pics show brass flakes and brass colored oil

brass flakes.jpgbrass in suspension.jpgbrass settle out.jpg
 

.RC.

Senior Member
Joined
Nov 27, 2012
Messages
770
Location
Qld, Australia
I may have found where your brass is coming from.

Aftermarket bearings.


While a USA made one

 

D6c10K

Senior Member
Joined
Apr 1, 2008
Messages
681
Location
Iowa, USA
That's the only thing we could think of. With that much brass in the oil I wonder how close to flying apart it is. I once saw a D9 final drive that had a double handful of shrapnel in the final drive...and a split bull gear hub.
 

D6c10K

Senior Member
Joined
Apr 1, 2008
Messages
681
Location
Iowa, USA
I spoke to the guy that worked on it last time and he was less than enthusiastic about working on it. His idea was partly the age of the tractor and the cost since you have to pull both the final drive and the steering clutch to do the job.
I would tackle it myself if I had the necessary pullers for the sprockets and clutch flanges.
I did rent a puller from CAT to do the bevel gear shaft one time, but you end up renting it twice. Once to take it apart, do your repairs, and rent it again to put it back together. I'm guessing renting the sprocket press would be a bit more expensive.
Anyone know of a puller set for sale?
 
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