D6C Steering Clutches not completely releasing

[D6c10K]

Someone with more experience overhauling finals might comment, but I'd be a little concerned with the pinion gear flaking out as much as it is.

 

[D6 Merv]

pull the right hand brg cap off on the bevel gear; side that takes the thrust and visually check the brg.
Your in this deep and its only 6 bolts. That is the brg that gives all the trouble in there. It was actually updated to a larger brg on D6Ds from the previous C models. There is a cat service magazine article about regrinding the shaft to fit the improved brg if an owner wanted to do it.
As TC and Bob said its a slow and careful job setting up bevel gears and brgs so take your time. Also make sure you rotate the shaft at least 20 revolutions to force the rollers up on the brg ramps to make sure they are properly seated before checking preload; which is 30-40 inch pounds on a D6C

 

[Metalman 55]

Someone with more experience overhauling finals might comment, but I'd be a little concerned with the pinion gear flaking out as much as it is.

I wonder if these marks on the teeth are from some sins from the past where something broke & got wedged in the gears, chipping them? To me it does not look like anything recent, but not having much experience with such things, cannot say for sure. Can anyone else weigh in on the marks on the gear teeth??

BTW D6C10K, with your problem with the steering clutch's not releasing, did you change all the disc assemblies & metal discs on yours? Were the inside splines on your hubs rough like mine are (see pics)? We have decided to buy all new disc assemblies & metal discs & just clean up the rough on the inner splines.

 

[Scrub Puller]

Yair . . . Metalman55. I believe what you see is wear and tear, possibly made worse by a worn bearing in the past.

In my experience on larger tractors the gears hold up fairly well until a worn bearing allows some misalignment and they don't start popping teeth off wholesale until there is a complete bearing failure.

When we got severe spalling it was standard practice to swap gears to the other side to present a better face on the load side.

Cheers.

 

[D6c10K]

BTW D6C10K, with your problem with the steering clutch's not releasing, did you change all the disc assemblies & metal discs on yours? Were the inside splines on your hubs rough like mine are (see pics)? We have decided to buy all new disc assemblies & metal discs & just clean up the rough on the inner splines.

I didn't replace any of the discs as the stack height was good and none were warped. Your drum looks to be grooved on the top of the spline teeth from the edges of the steel discs but not so much down in the splines. I had the same kind of wear but perhaps not quite as much.
If there isn't much wear down in the splines I think taking a disc sander to the tops of the splines would be fine......I think I did the same thing to mine the first time I had it apart.
I did have a small amount of wear down in the splines from the disc teeth but the local shop didn't think it was a concern. I did stone/file the splines some just to be sure.

During this last go around I was just about frustrated enough to replace everything in sight but that gets pretty expensive. Mostly I was fighting with a low oil pressure to the clutches. Trying to get that fixed is was led me to make my own full-circle clutch seals.

 

[Old Magnet]

D610K,did you have a chance to try out your full circle clutch seals and could you share the results please.

 

[tctractors]

Just my thoughts, but those plates, drum and hub look very good to me, the marks on the top of the splines are nothing that would get me spending coins, just swap the clutch over to the other sides would be the only thing I would do, the top pinion spins very fast and is often found knackered like the thing you have, a CAT Classic Part is the best way to go on this item, don't forget the bearing is pinned also don't use a cutting torch to Nip things through as you will damage the shape of the housing/s. tctractors

 

[D6c10K]

D610K,did you have a chance to try out your full circle clutch seals and could you share the results please.

So far the seals seem to be working fine. I ran the machine with the bevel gear case open and they were sealing up good. The original seals spray oil out at the end gaps on the seal....the full circle seals hardly leak a drop. You can't see the clutch plates in assembly, but I could tell the clutch was releasing because of the oil movement out of the clutch drum when the clutch was released/engaged.

The pressures came up quite a bit with the new seals...still just a little below spec. but I think that's probably caused from something else. Two likely suspects: trans relief valve bypasses more oil than seems normal and the clutch control valve bypass that lubes the bevel gear bearings seems excessive too. With pressure close to spec. I decided not to replace more parts.

All said, I still get a little clutch drag when cold....don't think it's ever going to release like a dry clutch. With the double reduction of the final drives it doesn't take much to move the tractor.

 

[Old Magnet]

Thanks for the info. Seems you have done about all that is practical. Some drag when cold is expected.

 

[oldirt]

I had a final rebuilt in my 6D a year and a half ago, used a cat pinion, but replaced the outer gears with cat classic. they ran 116 hours till the intermediate pinion shelled out taking the other outer gears with it.

my advise is never ever use cat classic anything. There is NO cat warranty on any of that "classic" junk. I was lucky, no tooth got caught between gears and destroyed the case. this was 10G that I didn't need to spend.

 

[tctractors]

I use plenty of "classic" junk gears but I do think the C.G.R. stuff is O.K. the Classic junk has the same Warranty I think as pucker CAT? anyhow there is often other variable points that cause trouble within a gear train that might be the reason of early failing, so I am not put off using lower cost gear sets, some of my customers will only have the genuine parts fitted to their tractors, I don't try to sway anyone to buy anything usualy just giving the customer the parts list of items I need letting them sort out the requirements, the "classic" junk range is better than lots of junk that is being sold at this time, I probably do more F/Drives than anyone else in the U.K. at this moment so my comment is a fair outlook on things.
tctractors

 

[oldirt]

I might have been better off buying the c.g.r. parts here, but cat didn't sell them and was pushing their "classic" aftermarket parts. I have used c.g.r. parts several times before and they have all been fine.

I just thought my experience might help somebody else avoid this kind of a disaster. wish I could have had you come over and help me with it. I did use all new bearings/seals all the way and replaced them all over again after all the metal went through them.

 

[Bob/Ont]

I had a final rebuilt in my 6D a year and a half ago, used a cat pinion, but replaced the outer gears with cat classic. they ran 116 hours till the intermediate pinion shelled out taking the other outer gears with it.

my advise is never ever use cat classic anything. There is NO cat warranty on any of that "classic" junk. I was lucky, no tooth got caught between gears and destroyed the case. this was 10G that I didn't need to spend.

Better to get good used cat parts than Classic or any aftermarket. I saw a Chineese bull gear destroy the steering clutch and bevel gear case of a mint condition 13X 955. Some $avings.
Later Bob

 

[Metalman 55]

We pulled the hub off on the "abuse" side of the bevel gear to expose the bearing & race in the hub & all looks good we think. We do not plan to remove the bearing from the shaft at this point. We plan to tighten up the backlash a bit more by moving one shim to the opp side then check the preload. The thinnest shim appears to be about .007", so thought we would try that first. Can anyone weigh in on this while it is still apart?

 

[Old Magnet]

One thing leads to another....the ring gear needs to be removed to get an accurate pre-load torque on the shaft once your shims are set. As mentioned torque should be 30 - 40 in-lbs although up to 60 in-lbs is probably ok. Might be able to reduce some of that back lash in the process.

 

[Metalman 55]

One thing leads to another....the ring gear needs to be removed to get an accurate pre-load torque on the shaft once your shims are set. As mentioned torque should be 30 - 40 in-lbs although up to 60 in-lbs is probably ok. Might be able to reduce some of that back lash in the process.

Ok, thanks for the additional information. We were glad to find the bearing to be in good shape.

 

[catfxr]

The actual spec for this test is 275 psi +- 25 psi, at idle, at operating temp with the clutches disengaged

 

[Metalman 55]

We were able to locate a used "Genuine Cat" LH top pinion from our local cat dealer to replace the one with the wear for reasonable cost. All other parts & seals appear to be readily available too, so hope to start putting things back together in a few days.

For the reinstall of the hubs that go back on the bevel gear shaft & the top pinions, someone with extensive experience mentioned that you do not use the retaining nuts to pull the hubs on, rather they need to be pressed on. Our manual is not clear on the reinstall of those components. Can I get any information or diagrams on what kind of hardware in required in order to press the hubs back in place?

 

[D6c10K]

Here's the manual pages:


View attachment Cat0001.pdf


View attachment Cat0002.pdf

I'll get the inside hub pages shortly....

 

[D6c10K]

Here's the inner hub page: