Arrma Fury - problems

[poombah]

Hi Guys,

I was on the Arrma "goforit" Forum and was recommended to join here. Been a Tamiya guy for about 15 years and rebuilt my own cars modifying them (TA03F, TT01D, TT01E).

Been keen to try offroading - after about 2 months of research and strong recommendation from a friend decided on the Arrma Fury 2014 BLS.. went to hobby store and they had the 2013 BLX on super duper sale price so opted pay the small extra and get the BLX instead.

Having a few dramas now with the Arrma Fury... as mentioned bought it brand new 7 days ago and have had the diff spider gears exploded after 2 days (2 full battery runs). I've been pretty tame with the car - run mainly on grass (ie park/oval) and on soft yellow sand (construction site)... not tried to jump it or do anything exciting at all still getting used to the handling (and SPEED) compared to my Tamiyas. After diagnosing the diff as the fault I took the diff in to where I bought it and they rebuilt under warranty - but used molyendium (sp?) grease instead of silicone oil as they recommended this.Put diff back, regreased and re-assembled.

Car ran again for about 10 minutes fine then started making griding noises. Took it all apart again to check for issues - reset the clutch/slipper - reset the gear mesh numerous times. Ran just motor and transmission fine but soon as reassembled and load on the wheels grinding noise.

Took car back to store and they drove it around carpark - i could just hear the noise but they said they couldnt hear anything and car seemed fine.. told me to take it out and give it some proper hard running and if noise got worse to take it back. Lunchtime same day took it to oval accross from my work - drove hte car 15 metres, turned around and drove it back towards me.. lost power and it just started griding on the spot.

Have taken complete car back to store this time.... feeling a bit miffed after doing all the research and deciding on Arrma (seemed to be best price point and reliable) - really just wanted something i could drive on deep grass, sand etc. I've driven my tamiya 1/10th road cars like 100x times harder than this and never broken anything except where ive crashed and maybe snapped an arm or something... Driven this Fury like a gentleman and aside from a few light scratches on the cover and dirty tyres the car still looks like new.

Just wondering if anyone else experienced these issues... just not sure if i should be asking for them to replace the chassis under warranty - have no faith in the car considering how gentle ive been to it and it has broken twice in the first week.

Cheers.

 

[poombah]

Heard back from store this evening. They have rebuild the diff with 2014 parts and hopefully we should be good to go... *fingers crossed*

 

[Aflan]

I am not sure...But the wise men and women can correct me if I am wrong...
But there was/is a problem with the washer in the diff of the mojave and fury's 2014 versions...They are to thin...Which causes to movement in the diff, and eventually leeds to a nice grind to make some coffee with...See other thread of mine with a picture...
When you use the 2013 replacement set all will be well...Good luck...

Erik
aka Aflan

 

[Unusual RC]

First of all, welcome!

Indeed Aflan is right.
The last delivered BLX cars featured diff problems. I have 2 Mojave BLX's with a serial number which differs over 4000 increments.
The highest serial got the same problems. The lower one has been punished with 3S 5000mAh without any problems.

The rebuild kit works! Install it and you will be fine! Highly recommended!
And I got it under warranty.

And do not be fooled! The diff needs silicon diff oil. 10.000 weight is default. For off-road you can go easily to 5000. I am currently running 7000 in my rebuild version.

 

[poombah]

Thanks - gave the car first proper bash today with another mate - made a jump from some scrap wood and had a ball. Car is transformed now - have to back the slipper/clutch off so i can stop the bloody thing wheel standing - if you full throttle it does backflips!! When i first got the car it would barely lift the front wheels.

Thanks for the tip on silicone oil - the guys at the shop who are doing the warranty have put the grease in and stand by it - car has 2 year warranty so i don't want to go an change it to the oil and have it upset the guys providing the warranty.

 

[Unusual RC]

That is also my experience with my Mojave/Fury BLX on 2S: Backflips from a dead start, and even wheelies possible from half throttle to full throttle.

On 3S things get mental! Different wheels and better shocks needed to keep things in a straight line

The diff is designed to work with silicon oil.
Grease can be used but will give more wear.
Since the oil is much thinner smaller dimension tolerances can create problems with the diff. So adding very thick grease will solve those to start with. But it also makes the diff function less good.
You could notice the difference when you turn on tarmac. With grease the turning circle becomes larger.

For bashing, no problem.
For racing, go for silicon oil!

 

[poombah]

Fingers crossed it all stays together... Had another day of driving and nothing broke.... Confidence restored

 

[mrbelloso]

Hi poombah, great that your problem was solved. Now enjoy the ride.

 

[poombah]

Thanks - just relieved - fanciest spec'd RC car id bought to date couldnt believe id managed to break it so easily - just looking forward to having some fun in it now... so hilarious wheel it wheel stands just love it.

 

[mrbelloso]

No problem mate, hope you enjoy it as much as i do with my kids.

 

[FuryGuy]

I had a road race today. DESTROYED the diff. Rebuilt it twice at the track. The first time to take a look because it is a known issue, but didn't see anything wrong even though it made the grinding noise. I stopped immediately hoping to catch it soon. I ran it a few laps and it did it again. I had the original diff with me and used the shims out of it. That helped, but, I think the gears where already shot at that point.

I have one more new diff. I am going to add the extra shims before I run it. I think it is a compound issue. The diff probably needs to be shimmed and the fact that the truck has insane torque. The guys at the track couldn't believe it was a stock motor / ESC.

I would recommend shimming it out of the box.

Hope this helps!

 

[Unusual RC]

It should not be necessary to shimm the diff in the gearbox housing.
Nevertheless I did it too to my Mojave who also had the diff problem. And it holds very good ever since!

 

[poombah]

Spoke too see - took for a run on the front lawn today and the steering servo seems to have packed it in. Has made weird noises since i got the car and i thought it was over-extending and fouling on the chassis so i backed it off on the remote - kept backing it off every so often - now in order for it not to make clicking/grinding noises in the steering its backed off to like 30% - but only works for a little while then either wont turn right or it gets stuck on full left lock. Opened the cover to ensure there was nothing fouling in there etc, and the steering works fine when off the ground but as soon as wheels have contact with the ground - ie load - just plays up.

back to the store again for warranty hopefully...

 

[Unusual RC]

The plastic gears, I tell ya
Both my Mojave's have aftermarket full metal gear upgrade servos installed

 

[poombah]

Did they fix under warranty or?

Anything else i can expect to break? just want to drive this thing without having it break every week.

 

[Unusual RC]

I did not bother, bought some Savox alternatives anyway.

But servo often are replaced under warranty, many got them replaced by their reseller or distributor. But they will break again...plastic gears are no good on trucks and cars

 

[poombah]

Went to store and they wont repair under warranty.

Have ordered these parts online $18.90 including shipping (http://www.arrma-rc.com/part-info2.php?partNo=AR390093) as the store i bought car from wanted ~$36.

Hoping they fit the original housing - cant find anything anywhere to say they don't and Arrma lists this part specifically as the upgrade for the ADS-7 servo.

 

[Unusual RC]

This works, and is cheaper than a new servo with metal gears.

It is up to the shop if they replace a new servo. In most cases it is user error. But unfortunately these plastic Arrma gears are too weak for even the servo itself. Quite powerful for an RTR servo

 

[FuryGuy]

Did they fix under warranty or?

Anything else i can expect to break? just want to drive this thing without having it break every week.

The diff is the only issue I have had. I did install my Savox from the get go though.

 

[poombah]

Do the metal gears in AR390093 suit the standard ADS-7 case? Arrma support page on Facebook contact tells me I need to get the metal casing too? There webpage mentions nothing of this.

I've got a spare futaba 3003 servo spare I'm going to try in meantime whilst waiting for new gears to arrive.