208d planetary

Firewoodjoe · April 03, 2020, 02:40:58 PM

So one planetary was getting hot. Torn it off and I see lots of metal flake and it is the axle shaft and outer ring gear sliding out and rubbing on the spider. Creating metal. Everything else looks good and only one brass pin has a tad bit of movent. What is supposed to keep the axle shaft from walking and the smaller center gear that slides on the end of the axle shaft also slides more up to the snap ring. No spacer washers anywhere. I'll post a pic if necessary. Thanks.

Firewoodjoe · April 03, 2020, 02:50:53 PM

Correction the shaft itself doesn't move only the small gear and large outer gear slides out and rubs on the spider. I hate to tear another one apart just to see.

Firewoodjoe · April 03, 2020, 06:22:09 PM

So I couldn't resist and tore the opposite side off also. It's identical except for the wear and shavings. I was starting to think it's all from a previous problem that had been fixed. So I cleaned it all and reassembled. Well the opposite side slid together good. The problem side I couldn't seem to push the spider tight by hand I had to draw it tight with the bolts. Didn't seem to go hard but harder than I could push. So I'm waiting to hear from one out there. It's assembled and ready for oil but I won't put any in until I hear something. Sorry for the multiple post. I just get impatient and end up tearing into things🤓

barbender · April 04, 2020, 12:55:28 AM

I've made it 44 years without having to tear apart a planetary, and if I never do that's ok by me😁 Therefore I am no help at all in this situation 🤷‍♂️

nativewolf · April 04, 2020, 05:33:10 AM

@Firewoodjoe -wish I could offer insight. However, I'd be really careful about putting it back together, making sure the metal is out. What was causing the issue? is a bearing or seal shot?

bushmechanic · April 04, 2020, 06:04:56 AM

Hello Firewoodjoe, if memory serves me those ring gears have just a pin coming off the bearing nut that you have to line up in order for it to fit together. The hole in the ring gear is impossible to see when trying to assemble it so I use the closest spline and mark it on the outside to get in the general area, then move it to the right or left until it fits properly. If you had to force it together you may have the pin damaged now. To answer your first question the axle float is controlled by the pin in the center of the planetary cover, if there is too much end play you can adjust by driving the center inwards when it is all installed. Hope this helps.

Firewoodjoe · April 04, 2020, 07:57:37 AM

Thanks guys. The ring gear slides over the end of the spindle which has splines. There is no peg on the wheel bearing nut just smooth. Also the outer spider cover is solid. There is no adjustments except the outer wheal bearing.

Firewoodjoe · April 04, 2020, 08:05:20 AM

Firewoodjoe · April 04, 2020, 08:06:05 AM

Dang maybe that was the peg right there.

Firewoodjoe · April 04, 2020, 08:06:43 AM

Firewoodjoe · April 04, 2020, 08:07:22 AM

Firewoodjoe · April 04, 2020, 08:26:49 AM

Quote from: bushmechanic on April 04, 2020, 06:04:56 AM
Hello Firewoodjoe, if memory serves me those ring gears have just a pin coming off the bearing nut that you have to line up in order for it to fit together. The hole in the ring gear is impossible to see when trying to assemble it so I use the closest spline and mark it on the outside to get in the general area, then move it to the right or left until it fits properly. If you had to force it together you may have the pin damaged now. To answer your first question the axle float is controlled by the pin in the center of the planetary cover, if there is too much end play you can adjust by driving the center inwards when it is all installed. Hope this helps.

Well it's looking like you are spot on. I apologize for my speedy ignorance. How do u determine how much play the axle shaft is supposed to have.

bushmechanic · April 04, 2020, 11:29:47 AM

I'm not sure exactly what the clearance would be, I'd just give it a few taps till it touches and that should do it. The pin needs to be on the nut because that is the lock for the nut. When the pin is in the hole of the ring gear that prevents the nut from backing off. I've seen the wheel come off that model because the nut backed off. I've only saw that design on the 208's, others have a split wheel nut with a pinch bolt, and no hole in the ring gear.

Firewoodjoe · April 05, 2020, 05:43:56 PM

Found the problem. The tall ring gear is from the problem side and it is tight against the spider cover before the bolted surfaces touch. That's with the dowel pin in the hole on ring gear as it should be. I checked everything with my calipers and this is the only difference between the right and left wheel.

Firewoodjoe · April 05, 2020, 05:59:33 PM

Using a straight edge the center gear is the correct depth. Only the ring gear teeth are out about .300. Only option I see is machine the ring gear teeth down but that would leave less teeth surface area or find the correct ring gear. Casting number on the old/correct wheel is RS47. No numbers on the newer/taller ring gear. Also just for reference if anyone needs to know I wrote down the bearing number tm716649. Thanks

Firewoodjoe · April 05, 2020, 10:09:47 PM

I think I'm going to machine the tall ring gear down or space the spider cover out. What do you think?

FFLM · April 06, 2020, 04:54:27 AM

Joe if my memory serves me correctly, that taller ring gear would be from a C4 Treefarmer, I ran into the same issue about 10 years ago. Last time I purchased a new ring gear it was about $700.00. Having the gear machined may work for you, good luck.

bushmechanic · April 06, 2020, 05:14:33 AM

Good catch on the different parts! Is there a hole in the back of the narrower ring gear? If not it may be from an older model of that planetary. The 208's that I have worked on had a different cover on them from the older ones. On the earlier covers it was just the pins and the gears with the gears being held on with circlips. The 208 cover has the gears held in place with a big plate and three spacer blocks that are bolted down with six 3/8 bolts. Seems to be a beefier design but when the fail they break up in a grand fashion! I think you need to find the right ring gear, to machine that it's going to be difficult as they are hardened for wear. It may be that the wrong gear is the non problem side, I'll check my garage I think I have an older one there and I'll measure it. Looking at the pic's the gear seems too far in the hub on the non problem side. The gears run thousands of an inch from the planetary cover and that looks like fractions on an inch. What I'm getting at is the contact area is not the full gear when it's bolted together.

Firewoodjoe · April 06, 2020, 06:20:48 AM

Quote from: bushmechanic on April 06, 2020, 05:14:33 AM
Good catch on the different parts! Is there a hole in the back of the narrower ring gear? If not it may be from an older model of that planetary. The 208's that I have worked on had a different cover on them from the older ones. On the earlier covers it was just the pins and the gears with the gears being held on with circlips. The 208 cover has the gears held in place with a big plate and three spacer blocks that are bolted down with six 3/8 bolts. Seems to be a beefier design but when the fail they break up in a grand fashion! I think you need to find the right ring gear, to machine that it's going to be difficult as they are hardened for wear. It may be that the wrong gear is the non problem side, I'll check my garage I think I have an older one there and I'll measure it. Looking at the pic's the gear seems too far in the hub on the non problem side. The gears run thousands of an inch from the planetary cover and that looks like fractions on an inch. What I'm getting at is the contact area is not the full gear when it's bolted together.

The covers are the beefier ones with the plate and wired bolts. Both sides have the dowel pin. They are both identical. Except for the taller ring gear. I also have thought about the shorter ring gear sitting in. The spider plate and pinion gears are a "fixed" position and the ring gear is a "fixed" position. That means the gears would not have the full surface area if the ring gear is sitting to deep. But it's not deeper than the single center gear that's on the axle shaft. And those both ride on the same gears. Just one inside and one outside. 🤔 But that one is not the problem side. It may be weaker but only time would tell that. And the taller one may be more correct in the case it needs to be thousandths of an inch from the spider plate, but it gets hot! Like wood stove hot and is visually wearing into the plate. And as I said I can't push the spider plate tight. The bolts must draw it in that last little bit.

bushmechanic · April 06, 2020, 06:57:05 AM

Here's a pic of the older stuff and a measurement of the thickness of the ring gear, might help. If you drive that center dowel in it keeps the side axle from walking out.

Firewoodjoe · April 06, 2020, 07:14:04 AM

That measurement was identical on both my ring gears. Only the total exterior height was tall. (As picture shows with straight edge) I'll measure mine again so I have the actual numbers. What if I made a gasket/spacer between the spider and hub bolt flange/housing. Would that make it to weak? Even if it was very thin it would have to help.

Firewoodjoe · April 06, 2020, 07:24:16 AM

Sorry I see u measured face down. That would be the same as my straight edge measurement.

Firewoodjoe · April 06, 2020, 07:45:21 AM

Firewoodjoe · April 06, 2020, 09:54:02 AM

Well just discovered something else. The problem side doesn't have the washers between the pinion gears and the spider. The opposite side/none problem side has the washers/spacers. Does anyone know who I could call that would be able to have a diagram and the parts I need. Thanks.

snowstorm · April 06, 2020, 06:59:41 PM

harold's logging in hamden me

Firewoodjoe · April 06, 2020, 07:26:34 PM

Thanks. I have the gear at my machinist buddy. He already cut down the outside and working on the inside. I'm hoping that works. Quickest fix and way cheaper. Also I plan on just finding some appropriate size trust washers for the pinion gears.

Firewoodjoe · April 07, 2020, 01:10:22 PM

Firewoodjoe · April 07, 2020, 01:11:28 PM

Done deal. Took some off the very top of the teeth and the ridge just under the teeth just for clearance. Time will tell soon.

GRANITEstateMP · April 08, 2020, 08:55:58 AM

Let us know how it works out. I second Snowstorm on Harold's Logging in Maine. I called them years ago and did a not great job describing my problem over the phone. 2 days later the correct parts were at my doorstep, and a copied diagram in the box!