Notorious Need some help

[bicketybam]

Just tested my Notorious after replacing the front diff pinion gear and initially it ran fine. After a few minutes and a few jumps it is making a noise and stuttering on hard acceleration. If I go easy off the line it doesn't do it. I made a video but it doesn't seem as pronounced as it does it person. But trust me....something is not right. Anybody have any ideas?

 

[Krathead]

I took my Kraton out the other day and it did the exact same thing. If I go real easy it is ok but hit it and it stutters. Like it can't take the amp draw. I'll be watching this.

 

[bicketybam]

I took my Kraton out the other day and it did the exact same thing. If I go real easy it is ok but hit it and it stutters. Like it can't take the amp draw. I'll be watching this.

I'm running a brand new BLX185 ESC and it did it with the previous ESC. I have a spare motor. Maybe I should swap that in and see if it makes a difference. But I still can't be sure it's not a diff slipping.....

 

[-Dusty-]

I am probably wrong but I heard this similar sound in another video a while back except it was an e-revo. Turns out the cylinder (not sure if its the right term) in the motor was all cracked up

 

[joostin420]

similar?

https://www.arrmaforum.com/threads/nasty-noise-from-center-differential.8620/

 

[Mr.Duke]

Sounds like mine after I rounded off the tips of 4 of the crown gear teeth. Thought it was an electrical stutter at first but got much worse the higher I was in the punch setting.
Pulled the front diff, cleaned off the grease and this....

 

[bicketybam]

similar?

https://www.arrmaforum.com/threads/nasty-noise-from-center-differential.8620/

He removed the video but it's not as bad as his was.

 

[bicketybam]

Sounds like mine after I rounded off the tips of 4 of the crown gear teeth. Thought it was an electrical stutter at first but got much worse the higher I was in the punch setting.
Pulled the front diff, cleaned off the grease and this....

I'll pull the diffs again and check. But as of yesterday they were good.

 

[Krathead]

Mine seems more like a power problem. I'm checking connections first.

 

[olds97_lss]

Odd sound for sure. Doesn't sound like gears hopping teeth like my outcast did when I knocked the tips off a few teeth on the ring gear. It sounded like a quick pop pop pop sound. Almost sounds like a center diff cup or pinion is slipping on the shaft. Then again, it could just be the camera taking the harshness out of the sound since you mentioned it sounds more pronounced in person.

 

[Drtybird]

Check bearing to housing tolerance to be sure you don't have any movement under load

 

[Rich Duperbash]

I'd make sure your drive cup isn't slipping on the input shaft. Might also check your diff cover is flush and tightened evenly. Sometimes persistent slipping can be from a cracked diff case. I've cracked a few on the bottom chassis plate area. Couldn't see it until removing the case off the truck. I'm assuming your crown gear is healthy ?. Also shim the crown gear side bearing with 2-3 Tekno #1222 shims.

 

[Jerry-rigged]

Check the bevel gears inside the diff rear diff. That is my guess.

 

[bicketybam]

Ok, tested a few things out. First I think the best way to describe what I'm experiencing is "chattering." It's not like gears stripping and if it were, I usually will experience the slipping under heavy braking....and I'm not. Have you ever had one of your motor leads come lose? You know how the motor is when that happens? It's like a smaller scale of that. And to reporoduce the symptoms, I have to go from no throttle to nearly pinned instantly. If I go zero to nearly pinned but take just a fraction of a second longer to do it, no chatter. If I'm at half throttle and go full, no chatter. It's just from no throttle to instantly pinned.

So today I swapped motors to a spare and dropped the pinion from 16t to 13t. I don't understand why every other 1/8 scale Arrma has a 2 step gap from normal to speed (well, the Kraton is now 3 since they went to 15t). The Notorious goes from 12t to 16t. That's quite a jump. I'm thinking 16t, with those big Backflips and the graphene batteries I run is just too much. I may buy a 14t, but all I had laying around was 12 and 13 so I went with 13. Initial results were much better but it would still chatter a bit when I would go WOT from a dead stop. I almost got through the whole battery when the truck just stopped and was making a sound like a motor lead had come off. Sure enough when I popped the body off I found this:

It just melted. I grabbed a temp gun and the motor was over 200 degrees. Yikes! The ESC was around 90, so not too bad. Then again it's 32 degrees out.

I think the Backflips have something to do with this. I know @olds97_lss had heat issues. When I had the Backflips off they felt like they weighed 5 pounds apiece. I may try a lighter tire. Plus they tear the poop out of my lawn, lol.

Anyway, I don't think it's a diff issue. I think it's electrical. My permanent solution may be lighter tires or an aftermarket ESC/motor combo.

 

[Krathead]

If everyone else is running them you should be able to also. I think my problem is very similar to yours but it mine cuts right out if I give it too much throttle. What happened to you should not have happened, even with backflips.

 

[Jerry-rigged]

Have you vented your tires? If they feel like 5lbs each, they may be water logged, with all that snow running.

Glad you found the stuttering issue. And a cheap fix! Winning! LOL

 

[Drtybird]

What would be the chance that it could have affected the ESC

 

[olds97_lss]

For their size, the backflips are lighter than the proline trenchers 3.8's I was running. I weighed them on a USPS scale, the backflips are 12.5oz whereas the prolines were 13.4oz. I have a mildly used set of kraton stock tires I might try next season, they are 10.5oz. I'm currenlty running a set of t-maxx 3.3 tires/wheels that are 11.5.oz with I think a 15T pinion, but they really hamper my in air control and the rim cuts through the sidewall when running at skateparks, which is where I spend most of my time. Kind of why I really preferred the proline trenchers. THe sidewall was thicker, but also taller like the backflips, so there was more rubber between the ground and rim to absorb the impact, which made them less likely to cut the sidewalls up.

I may try going back to the prolines and just live with the fact I can't run in the grass constantly, or take it a bit easier. I just like those tires too much to give up on them. I have them on my erevo, and it's so much lighter of a truck, you really notice the added weight of those tires on it. On the outcast, they don't feel as bulky. I have a set on my savage flux as well and really like them there too.

Kind of funny... I have 2.8" trenchers on both my stampede 4x4 and converted ejato. I just really like that tire in both sizes. lol!

 

[bicketybam]

The plot thickens.

Took out my Notorious and within 3 minutes it was just running in circles. One of the rear tires had no power to it. Take it inside and pull the rear diff:

Sun gear and pin were in pieces. Surely this must have been the source of my issues! I rebuild the diff using all new parts except for the ring gear cover. I put it back together and go test. I still have the chattering and after 10 minutes the motor is 205 degrees. FML. So what haven't I checked .......ok, the center diff. I have a brand new one from Jenny's RC. I take the truck inside and disassemble (this is where that Markhor top deck just blows to have). I shim the new diff and replace the fluid with 500k. As I'm putting the truck back together something catches my eye....

Take a look at where the CVD goes into the diff cup. WTF?!

That's a new one for me! It was actually hitting the a-arm pin and catching. So I replaced the whole CVD and reassembled the truck. I also swapped out the backflips for the Trenchers I run on my Kraton. I go out and test and I only heard a slight chatter once. But the Trenchers rub against the body I can't win.

Tomorrow I'm going to out the Backflips back on and running for a bit to check for the chatter and excessive motor temps. I have to tell you this truck has me baffled......

 

[olds97_lss]

That CVD thing happened to my bashing buddy on his talion. I've read that people replace those when they wear, the pins, but I don't know how they keep them from moving. Green or red threadlock maybe?