Diff. Ring Gear Failures

[AmiSMB]

Mine has not failed but I have noticed little pieces at the outer edge of some of the teeth are missing. Looks to me like the rear ring gear is cast and maybe then have minimal finishing. All the 1/8th ring gears I have seen look like they are completely machined from solid metal.

[Gonzo]

Originally Posted by AmiSMB

Mine has not failed but I have noticed little pieces at the outer edge of some of the teeth are missing. Looks to me like the rear ring gear is cast and maybe then have minimal finishing. All the 1/8th ring gears I have seen look like they are completely machined from solid metal.

Exactly, I'm also thinking little pockets of air or impurities in the molding process cause these failures. I received once a new ring gear with a corner missing, so it's completely possible that an imperfection is at the inside of a tooth.
Off course all the precautions we mentioned here will minimise stress on this gear and will minimise failures. But I also would prefer machined gears, that I can use untill they are worn instead of broken, even at a higher price (already broke 8 of them in a year and a half)

[dr_elvis]

as i said in the beginning of this thread, something is going really wrong with the diff ring gears. newer gearboxes have too much space for the bearings even if you drag the screws left and rightfrom the bearings like hell.

second problem is if you are using the R Spec or the plastic sidegards and the plastic rear brace on the pro spec car that there is too much flex an the rear drive shaft can knock on the button head screw in the rear slipper outdrive which causes stress on the rear diff ring gear too

third things are the bearings in the hole car - for aprox. 500 bucks imo bearings have to be more then just the cheapest crap on earth

and last but not least the drive shafts center rear and front and at all axles are not really straigtforward even more like mister hood's bow.

all in all too much stress on the complete driveline imo - and diff ring gears are only sintered and then hardend but not machined like the bevel gears.

But and this is the big plus of the car - it goes pretty well and makes you happy when driving it.

[slowjun]

Originally Posted by Gonzo

I've put a 5mm x 30mm tape in the same direction as the bevel axis, so longitudinally over the seatings of the bearings, both in upper and lower half.
Way easier than taping bearing per bearing, and the tape doesn't move because it makes some 90 degree turns once everything assembled.
If the slop would be sideways, different story...
Again, still testing this...

And what type of gear-grease would be best to use on the diff ring? A sort of type instead of a brand would be nice, so I could buy some non-RC quantities of it

Gonzo,

did this and problem solved, thanks for the Idea, at first i did not feel the need to do this but when i saw this thread. it made me thinking.. you guys had a point. after seing and reading thru here... arrived home and did as explained. then viola!!!! problem solved. and it did not even take any $$$ to solve the problem....

thanks guys,!!!!

[Gonzo]

The tape was not my idea originally, but worked for me to, that s why I posted it here.

Originally I put the tape as I mentioned above, but after a couple of runs you can carefully remove the "up standing" parts of the tape using a cutter, it will make the little bearings move more freely, but still no slop.

Now the slop on the bevel was away, I focused again on the sideways play of the diff. The manual of the normal DEX stated copper-copper, the manual of the R version stated copper-iron (iron on diff ring side). With the slop gone, I noticed the extra pressure from the iron shim is not needed for my car, so I use copper-copper on all my diffs now. Again, this lets them work more freely, and so far no breakages. I also think there are less sideways forces on the big bearings with copper-copper, because those bearings showed sideways play too soon on my car as well.

Should have done these things much earlier!

[dpackster1980]

Put electrictions tape where the bearings sit on both halves of the gearbox and no vertical movement on the input shaft like there was before?

So far so good and it's quieter too, fingers crossed.

I don't want to back the slipper off anymore as the slipper comes off really warm so if I back it off anymore it will cook the plates so it's got to be right.

Does this sound correct for setting the slipper?

[stegger]

How has this gone for people, anymore prob's ???

[JohnM]

Never had a problem with the diff gears in the first place

[mikeyscott]

Have had any probs with mine yet, but only been running my R since beginning of Jan. Was very careful when I build mine to get it spot on 2.8mm and done up properly etc.

Keep meaning to get a spare gear though.

It's not related to the potential updated part as highlighted in the Petit article?

http://www.oople.com/rc/photos/petit2011/index.html