E-Revo Diff Question
 

Got an E-Revo a few months ago and finally got it all put together. Im running the mamba monster system on 6S. I keep having problems with the rear diff. Any suggestions or clues as to why? Is 6S too much?
Anything helps! Thanks!!!

It's because traxxas is garbage! It "should" be able to handle a 6s because they advertise and sell it like it can, BUT:

Apparently.

The stock differentials don't really hold up to 6S, no. The problem is that the differential casings (plastic) flex under load and allow the ring and pinion gears to change mesh, which blows up the teeth, as you've no doubt already seen.

This is a problem on both Traxxas Monster Trucks (Maxx & Revo).

Replacing the differential cases with aluminum cases will solve most diff issues you'll run into. The rear diff takes a much harder beating than the front end, so if you're strapped for cash, doing the rear end first is an option that works.

If you blow the spider gears (cup comes apart) later, you can fix that with an aluminum diff cup. FLM makes these for the Revo & Maxx, and they include a modified ring gear that takes larger (M3) screws to boot. Integy, GH, and HR all make diff cups that take the regular M2.5 screws that bolt up to the original gears, however.

If you explode the diffs after that, your only option is the RC-Monster Hybrid diff cases, and those take 1/8 Scale diffs. Problem is, you'll be changing diff ratios (2.85:1 to 3.31:1) so you'll have to regear some.

Hope that answers your question. 6S is fun, but the truck requires some upgrades to handle it reliably.

Wait....hybrid diff case's for a revo? Since when???

I don't know how some of your brains think....:weird: If you buy something with quality money at a HIGH quality price NO ONE should have to spend more money for more parts to make it work properly like they advertise it should. Then they make more money at the parts counter on EXT diff cups and other Jag Off-Mickey Mouse set up's..:nod::rolleyes:

Traxxsucks= (The expensive name in RC) for plastic junk and non heat treated metals.

RC-Monster makes them.

Edit: They are currently out-of-stock. RC-Monster Mike says they'll be re-releasing them, however.

Haha, stick a MMM on a MBX and see how long it last on 6S lol. Nitro parts last longer than high end brushless, because they have less punch and harshness off the line, brushless are pretty near instant. I know, I've run them both. If Traxxas is the only crappy truck out there, why do manufacturers sell upgrade parts for almost all other brands as well? Because they all push the limits on parts, that's why. You're vitriol sounds personal to me and really doesn't contribute to solving his problem. Maybe he should go into the programming of the Esc and turn the punch down. More like a nitro.

Eta, Jr, a MM on 6S puts out 5-6 HP, that's extreme for a 1/10th car. No matter what the brand.

There is a big difference in a "upgrade" and/or a CRUTIAL/VITAL part to let it run like they say it can...:tire:

Vitriol? Nil.

EDIT: Let me add something, he never asked for a "solution"...... He only asked "WHY"..

Why? Because 6S is brutal for ANY 1/10 car. He asked if 6S was too much, Yes, if he's bashing and doing 25 foot jumps and backflips. Speed runs, probably not. Maybe he just doesn't know what the limits are yet and needs advice.

As mentioned the plastic diff case flexing is an issue, but the Revo ones do better than the Tmaxx ones ever did. Another thing is shimming the diffs to get rid of any play (too loose) or notchiness (too tight). You can play around with those stupid Traxxas Teflon washers but it's really best to get the right size shims for the pinion and the spider gears. Unfortunately you can only put shims on the pinion with Traxxas diffs, there's no room for them on the sides. Another thing is to get rid of any play in the drivetrain. Play causes shock loads to be transmitted everytime you gas or brake and they'll find the weakest link eventually.

+1 on that. The plastic shafts flex, so if you're still running into issues after replacing the diff cases and cups, this is something to look into once you're at that point. Shock loads are bad for anything in the driveline.

I have an e-maxx with a MMM 2200kv setup and have also had to replace the rear diff gears twice. In both instances, the rear diff gave out when landing standing backflips with the throttle still on, on 6s, sporting summit wheels and tires, complete set of steel driveshafts, with the slipper locked. Other than those two occasions, I've had no issues with jumps, wheelies, and general tearing up some grass and dirt.

From my experiences, no, Traxxas does not 'suck'. There is the same amount of logic in stating that they don't make their parts strong enough, and that they put too much power in their product. Personally, I'd rather have more power than the chassis can handle and use it smartly than have an underpowered chassis within the same price point. Of course, lots of power in a chassis that can handle it is best, but when choosing two from 'powerful/bulletproof/inexpensive'....
I think arguing that a brand 'sucks' because certain parts can't handle extreme abuse at the max ratings is a bit silly. The fact is electric motors have a much higher torque output relative to the watts/HP, and is near instant, when compared to nitro engines (which is what the diffs were originally designed for). Certain parts could be made better, which is what the aftermarket is for.

IMO I don't think they really flex that much, maybe a little at the ends but the splines keep them from twisting much in the middle. Either way I feel the bigger problem is the holes for the universals go from circles to ovals as you use the vehicle. This creates play, backlash and shock loads in the drivetrain.

If I owned a RC company, your my target customer! Oh yeah, they don't own the motors or the speedo's that their drive train can't handle. You don't need "extreme abuse" to grenade a traxxsucks diff, all you need is a 6s and a trigger finger. You act as if I don't know what I'm talking about, I've probably owned more traxxsucks garbage RC at one time or another then all the posters in this thread combined....

Well thank you everyone for their input! Maybe I should have worded it differently. Of course Im looking for a solution not just asking why. I know 6S is a lot of power, but man is it fun!:nod:

I'm not 'acting' one way or another, simply sharing my experience. I consider the scenario where I had two rear diffs fail overly abusive. Just because you CAN do something with a given product, doesn't mean it SHOULD hold. There are no stated warnings not to jump 30ft high with a MT, even though it may be capable of doing so, just as there are no stated warnings not to do standing backflips with oversized tires. The specs simply state that the truck is capable of running 6s, not that you can abuse to a given point and not incur damage. Ideally, it should not fail, but at the price point of the truck itself, I'm one that can look past that detail. I no longer attempt standing backflips as often, but when I do I just make sure to tap the brakes mid air to transfer some weight from the rear to the front, inducing a flatter landing, and taking stress of the drivetrain, and the diffs have held up well.

Any idea as to where the best place to get an aluminum case would be?

As expected, fan boy post.... As I mentioned, you do not need to "abuse" truck to grenade the diff, simply pull the throttle using a 6s with some traction. Traxxsucks obviously knows about the problems and does nothing to fix it.. That's a great company!! You deserve them!

Wow! I'm excited!! I must have some super rare, magical ring and pinion gears! Just give throttle with 6s while keeping traction you say? That's crazy, I've done just that but these gears just keep going. I wonder what I'm doing wrong :confused:

Yeah, you must have bought yours from the same guy that sold Jack his bean stalk....

meno1103: DNFTT

eBay. STRC Diff Case here.

Or Stormer has the blue Integy cases still.

That's about all I can find. Seems like it's harder to find Revo parts then Maxx parts, despite the Revo being the flagship now. Weird.

All brushless high power car diffs need shimming no1 put quality bearings in new diff no2 replace plastic diff case with alloy no3 lube with100wt oil not grease no4 diff problems solved

Not to put too fine a point on it but ANYTHING running 6S will need near constant maintenance.

Think NHRA top fuel/funny car where the engines get opened up on an average of every 5~10 MINUTES of run time.

If you don't mind spending more time working than running then stick with 6S.

It's possible to build a stock traxxas diff that will hold up to as well as anything else to 6S but it's not something I can explain in a few paragraphs and requires a through working knowledge of how to properly remove any trace of backlash without binding anything up. If you really want to a badazz traxxas diff take a set of diff cups to your friendly neighborhood machine shop and get them to make you some press in inserts for the blind side of the cup. You will also need several different sizes of shims, some grease with a droop point of at least 500F, and the ability to feel the difference between no backlash and binding.

I have cars and trucks that I run 6s in (5 in particular are a Savage flux, GT2Pe, DM-1 conversion and 2 Mugen ECO) none of which needs any "more" maintenance (because of a 6s) then any other unit I've owned. Some have said that this traxxsucks is a 10th scale and it needs work to handle a 6s and that's fine but they should not advertise this truck being able to handle it was my point..

funny vorza can handle 6 s power and is just as heavy. they use spiral cut gears for strength, no issues.

Truck aside, spiral cut gears don't really add any strength versus bevel cut, and cause other issues when you run the spiral in reverse. Helicals also have issues with axial loading (the helixes will push apart), so shock loads will actually harm them more then your standard bevel gear.

http://en.wikipedia.org/wiki/Gear#Helical

They actually wear harder. The real benefit to Helical Gears is that they are quiet, and don't whine like standard bevel cut gears at high RPM. The power transmission is also a little smoother, since there is more gear material in contact with itself, and the resulting friction reduces drive lash.

Bigger fan of bevel gears myself. Louder? Sure. But more suited to bad situation driving. :) Though I can see why Helical Gears are popular in racing, where you just drive a track.

New and revised RCM hybrid diff cases should be coming out soon (within a month according to Mike). Finally ERBE owners can kiss all their diff problems goodbye.

The single biggest issue I see with people blowing out diffs is they always run their slipper clutch too tight !

I have had my EREVO since the very first day they were released (bought the brushed version as the brushless version wasn't available) and I have never had a diff go bad , but I make sure that slipper is set right so it does its job and absorbs the shock loads put on the driveline from landing on throttle . I dont know why people think standing backflips are so cool when it probably is the most harmful thing you could do to your RC .

First off where have you EVER seen Traxxas advertising their vehicles capable of handling 6S.

I talk to their techs all the time and in private they even hedge when asked about 4S.

The most Traxxas has ever officially said run in their brushless rigs was 3S.

Be that as it may, I build Traxxas cars for 3 different people who all run 6S and none of them have much problem beyond a shorter maintenance interval on the driveline than one might have running 3 or 4 cell.

Oh and they are all street/rally cars. Two are 4x4 LCG slash converted to street and one is a rally and all 3 are fast as hell. :D

+1 on the slipper. If you are racing electric, slipper adjustment is your single most important tuning tool after tire selection.

As for the standing backflip, they do it for the same reason they used to roll reverse than slam forward to get wheelies back in the brushed motor days. Also the most harmful thing one could do to both motor and ESC.

"First off",, Right here strippy....:rolleyes:

I colored it in RED so you can see it better. OH, here's the link too....:tire:

http://traxxas.com/products/models/e...erevobrushless

◾Top Speed: 50+ with included Power Cell LiPo batteries, 65+mph All-Out!
◾Includes two Power Cell 5000mAh 3-Cell LiPo battery packs
◾Includes two LiPo Balance Chargers
◾Equipped with Castle Creation's Mamba Monster Brushless System
◾Traxxas TQi 2.4GHz Radio System with Docking Base
◾Equipped with RPM/speed, motor temperature, and voltage telemetry sensors
◾Up to 25.2 Volts of Massive Brushless Power
◾State-of-the-Art Integrated Chassis Design
◾Heavy-Duty 17mm Splined Aluminum Hex Hubs and Wheel Nuts
◾Hard-Anodized PTFE-Coated Aluminum GTR Shocks


That's great!.. I never talk to any manufacturer tech's because there is no need! (you probably did not get that so I'll break it down for ya) No need meaning the RC's I own don't break! If they do I know how to fix em!!:lol:

Really? That's cute! Please refer to the link I posted up top...:rolleyes:;)

Don't really care what you build, you could build a frickin Zephyr, the facts still remain!

Metal or a monument?:lol::rolleyes:

I sent you a PM with the link to this thread so you don't forget to come back! I know how you 4 post reading posters like to post...;)

Sorry.. I had to register JUST to respond to this..

I can't post URLs to other sites yet so I'll quote the overview page of the E-Revo Brushless Edition section of the official Traxxas website for you..

"Built For Brushless
We built the E-Revo for 6-cell LiPo and brushless power right from the start. For other companies, brushless-ready means just making some nominal provisions for battery and motor installation and letting the aftermarket develop the upgrades necessary to make it survive. Not Traxxas. We heard the call for more power so E-Revo was tested tough for durability with brutal 6S LiPo power and intense custom-wound brushless motors. For the uninitiated, this extreme 65+mph motor and battery combination is ordinarily a predictable recipe for a box full of twisted and mangled parts. Not so with the E-Revo Brushless Edition. E-Revo's driveline has been engineered to endure the kind of horsepower and punishment that's possible with today's motor and battery technology."

Don't get me wrong.. I LOVE my Revo. I have had it since the day after the 2.5 came out. That 2.5 was converted to a 3.3, then it had an OS21tm, then an LRP.28R and now I am in the process of converting it to a full on E-Revo (Not just a conversion kit, I'm swapping the chassis and everything).

The Revo is the only RC I own, but far from the only one I've driven. I LOVE my Revo and I think Traxxas is a fantasic company. However..

They really didn't design the diffs well at all. They are far too small and too weak to be considered durable for even the 3.3 nitro engine, much less a brushless motor on 6s. A truck that size, with that much traction and that much power should have had an 1/8 scale diff from the start. Which is how i found this thread in the first place.. Google for "rc monster hybrid diffs rerelease" brought me here because with as much money as i spent on replacement diffs through the years, i want something that is going to hold up to my new 2200kv brushless motor. Even if I'm only going to run it on 4s.

That may be true for the 1/10 scale stuff with the Velenion systems like the slash or rustler, etc.. but if you try to run a brushless revo on 3s you are only going to cook your battery, or fry your ESC. The voltage is just too low. You NEED at least 4s to run the Revo.

And one last point.. The newest brushless E-Revos come from the factory with 2 3s lipos and the ESC is wired in series.. If Traxxas never meant for the vehicle to be run on 6s, they sure are doing a great job of covering that up..

And hey, I'm not picking on you.. You asked a question and I'm answering it is all.. no hard feelings.

vorza done

OK guys, I like my crow with a lot of salt.

I'm a nitro MT guy because of all the problems I see and hear about from people trying to run large scale electrics.

Everyone I know who race 8th scale have tried electric and are moving back to nitro because they are tired of the constant trouble they are having with ESC's, BEC's, and servos burning up or failing after a short period of time.

We all race 2wd and 4wd 10th scale electric and have zero problems with that but every racer around here who runs 8th electric has been frustrated by a high failure rate of the three components I mentioned.

Either way, enjoy your dog piling on someone who got caught out writing checks with an alligator mouth that their hummingbird azz couldn't cash.

I'll be sure to read more on large scale electric before I run my suck in the future.