Anyone have bearing/diff issues?

[Patella]

Tore into the diff tonight and found some interesting things. I think what I found may explain a few of things I've noticed over the past couple of weeks. One of the first things I noticed from the start with my car is that when I would come off the throttle suddenly the rear end would want to whip around to the drivers side. I thought maybe it was just a weird torque issue as this is my first high powered brushless setup. The other thing is that I've felt like my car was a battery hog. Today I really noticed it when I had already burned through a 4000 and 2 5000's before most people had finished their second battery. When the rear end let go towards the end of the day I thought maybe I crunched my diff gears. Below is a pictorial of what I found when I tore into it tonight. Sorry if I don't know all the terminology when it comes to the internals.

This is what I found when I took the bulkhead off.




You can see the outside of the diff case melted and fused to the bearing.


Diff casing is gone.


Ring gear is shot.


Outer diff casing gear is shot too.



The good news is the the spider gears inside the diff look perfectly fine and still spin freely. When I looked at the manual it showed two shims between the bearing and the diff case and I could only find one. At this point I think I will need a new rear bulkhead (diff casing), new ring and big diff gear, new bearings and shims, and the diff housing as that frozen bearing tore it all up around the output shaft.

I don't know if it just got wet and froze up that first weekend we ran, but like I said I've always noticed the car's tendency to want to spin to the driver's side on decal since I first got it. Maybe it was just a bad bearing from the get go. Any thoughts?

Jake

[Szczerba]

Don't see any pictures.
What car you referring to? My Kyosho DRX has smoked rear axle carrier bearings pretty quick. I'll need to fix/upgrade soon.

Good thing you found your issue.

[Patella]

Sorry fixed the pics issue. Had tried to import the post over whole from my local forum and pics didn't come over.

I"m ordering new bearings for the whole rear end. One of my big wheel bearings lost a shield and was pretty gritty too. Going for rubber sealed.

[Szczerba]

You don't run any grease on the ring/pinion gears?

Also when I tore apart my DRX for the first time. There was only one diff bearing shim on one side as well.

[Patella]

I was just running it stock so whatever was in there.

[TURTLE]

Originally Posted by Patella

I was just running it stock so whatever was in there.

Yeah you need grease! Really the first thing you need to do when you get this car is open the diffs up, check them, grease them and make sure everything is in place.

I have blown two outer bearings on the knuckles in the rear, but that is it. I also rebuilt the entire car and greased EVERYTHING before I ever drove it.

Been driving mine now for almost a year with zero diff issues.

[Patella]

Originally Posted by TURTLE

Yeah you need grease! Really the first thing you need to do when you get this car is open the diffs up, check them, grease them and make sure everything is in place.

I have blown two outer bearings on the knuckles in the rear, but that is it. I also rebuilt the entire car and greased EVERYTHING before I ever drove it.

Been driving mine now for almost a year with zero diff issues.

Definitely a lesson learned. What are you using for grease in there? On payday i'm ordering everything to rebuild the rear end and a fresh set of rubber sealed bearings from Avid (1.00 a bearing). This car is my first high powered anything, I've always been a slow scaler type.

[TURTLE]

Originally Posted by Patella

Definitely a lesson learned. What are you using for grease in there? On payday i'm ordering everything to rebuild the rear end and a fresh set of rubber sealed bearings from Avid (1.00 a bearing). This car is my first high powered anything, I've always been a slow scaler type.

Inside the diffs I use fluids anywhere from, 3k to 7k depending on terrain and which diff it is going in. I also recommend going to 4 gears in each diff. For grease I use either tamiya grease, or full size automotive grease. The only thing, from my experience, that doesn't hold up well in go fast cars is marine grease. White lithium bicycle grease also works really well.

[Creepy Inc.]

Originally Posted by TURTLE

For grease I use either tamiya grease, or full size automotive grease. The only thing, from my experience, that doesn't hold up well in go fast cars is marine grease. White lithium bicycle grease also works really well.

DAMN IT!!! I just repacked all of my diff's with M Grease.

[TURTLE]

Originally Posted by Creepy Inc.

DAMN IT!!! I just repacked all of my diff's with M Grease.

Any why it doesn't work is because of how fast the diffs move. I used to run it in my TB-01. I checked them after a couple weeks and the grease had dried out and become a thin layer of tar on my diffs. The heat generated in the diffs drys the grease out pretty quickly.

The only luck I have with marine grease is in crawlers and that is because of the slower rate the diffs move and my constant submerging in water.

[Creepy Inc.]

Originally Posted by TURTLE

Any why it doesn't work is because of how fast the diffs move. I used to run it in my TB-01. I checked them after a couple weeks and the grease had dried out and become a thin layer of tar on my diffs. The heat generated in the diffs drys the grease out pretty quickly.

The only luck I have with marine grease is in crawlers and that is because of the slower rate the diffs move and my constant submerging in water.

I may be ok then, I actually used the the Marine grease the pack in the bearings of the diffs not the ring and pinion. Just like pictures shown above my diff bearings have become very dirty and sound like a peeper mill when turning. I've just cleaned them out with HPI Nitro ( HPI NITRO CAR CLEANER (HPI74116) | RC Planet ) then fill with grease. That cleaner is wicked for getting grit out of small spots and it melts oil off the shock bodies. Patella, one thing I've looked in to doing is replacing all of my bearings with high quality ones. If you read the description of these ( 12x18x4,#YCWK6701-2YS NB2,Metric, Radial Bearings ) they sound like they'd be perfect. It's just bit much to spend but, it may be cheaper then replacing cheap ones every other week. TURTLE have you ever bit the built and picked high dollar bearings?

[stormridersp]

Originally Posted by TURTLE

Inside the diffs I use fluids anywhere from, 3k to 7k depending on terrain and which diff it is going in. I also recommend going to 4 gears in each diff. For grease I use either tamiya grease, or full size automotive grease. The only thing, from my experience, that doesn't hold up well in go fast cars is marine grease. White lithium bicycle grease also works really well.

I've been testing grease a while ago. My favorite so far is the Molykote High Speed G-2001 Grease. Its water proof, corrosion protective, plastic-metal compatible, high speed, good lo-high working temperature and is lithium based.

[Creepy Inc.]

Originally Posted by Patella

There's one thing I found with mine that's weird. The manual shows two shims on the diff. Both being placed on the ring gear side of the diff. When I put mine back together I put one on each side by accident. Last night I tore them apart and placed both on the same side and, the mesh was way off. It was super tight. Maybe after you rebuild them try and play with the shim placement.