i need a indestructable rear diff, please help

[blueb8llz]

so my rear diff blew out for the second time. the first time, the ring gear's teeth was chipped off. and now this time, one of the ball bearings (attaches to diff/pinion gear) broke into pieces. so the diff/pinion gear and ring gears tooth is shaved. now my plastic diff case is sorta warped and cant close tight.

can anyone suggest me the best options for me are. i think i will need a new rear diff case, maybe a aluminum diff cup, ring gear and diff/pinion gear, shims, and whatever else i may need.
oh...maybe stronger better ball bearings haha. dont even know how they even exploded like that.
thanks for all help guys!

oops forget to tell you guys. im running a emaxx 3905 with 7xl/mmm on 4s

[suicideneil]

Easy.

1) UE ultralite diff with 6 or 8 spider gears, or just use the case and get ofna 1/8 scale inards.
2) FLM hybrid bulks and use the ofna or hotbodies inards again (buggy, rather than truggy gears).
3) Modify some Muggy or LST2 diffs to fit.

You can find a how-to in my Emaxx FAQ (scroll down, you'll see it).

[blueb8llz]

sorry neil . the diff section is totally all new to me. so your telling me i need the flm bulks to fit the UE diffs? whats the bare mininum i can get away with on making a better stronger diff? i sorta wanted one with no mods, just a direct fit. is there a place to just buy each thing seperatly since i dont need the whole set up. most places sell them with the front and rear diff.
sorry for the newb questions. like i said, the diff is all totally new to me.

[suicideneil]

The FLM HYBRID BULKS are what you need to use 1/8 scale diffs.

You could just use an alloy cup and case from FLM, but that wont fix the fact that stock emaxx diffs are rather shite, with only 4 spider gears, compared to 1/8 diffs that use 6 or 8 spider gears.

The cheapest solution would be the muggy/lst2 diffs which can be bought on ebay for like $20 each; a small amount of work is all thats required to have bullet proof diffs:

http://www.rc-monster.com/forum/showthread.php?t=9153

Much better and cheaper than messing around trying to make stock diffs stronger with an alloy cup and case.

FLM hybrids are similar to the UE VBS setup, or the UE ultralite case which fits any maxx bulks, and uses 1/8 scale inards. You can find a kit in the RCM store with hotbodies 1/8scale buggy diffs and the required pinion gear and bearings etc.

[lincpimp]

Interesting Neil, I am going to start making adapters to put the lst diffs/cases in maxx bulks. Just need to get a setup mocked up to get the correct dimensions.

[blueb8llz]

wow, thats a very informative and interesting thread to read. thanks neil. surprised why i never bothered to read that thread. i think i may still just go with the AL casing and cup.
im never really good at modding things so the direct bolt ons are best for me. plus, my spider gears never had any problems, it was always just the ring gear and pinion teeth.
i think the AL cups and casing would solve the flexing and issues.
heres what someone recomended me:
http://www.rc-monster.com/proddetail...zerdiff&cat=47
http://www.greatassemblyrc.com/Differential_Cases.cfm

[George16]

It's the flex of the plastic cups in addition to the flimsy 2mm screws that won't stand the power of brushless setups.

I'm running UE ultralite with 8 spiders on my diffs and they stand the power of the 1515 1Y on 6S.

If you don't want to spend a lot, just get the FLM or Nova-RC alum cup with 3mm screws.

[blueb8llz]

hey george16, thats funny how you said that, i was just looking at those nova cups on ebay. are these the ones your talking bout

http://cgi.ebay.com/DIFF-CUP-S-Maxx-Aluminum-Traxxas-2-5-3-3-Differential_W0QQitemZ330271679759QQcmdZViewItem?h ash=item330271679759&_trkparms=72%3A1205|39%3A1|66%3A2|65%3A12|240%3A13 18&_trksid=p3286.c0.m14
but it says pick the 3mm hole mounts only if i have modified gears. which i dont, im using the stock traxxas gears. will it still fit or no. if not, should i still get this with the 2mm screw holes? i think as long as i get this case, the screws shouldnt matter tooo much would it.
one last thing, should i purchase a AL casing? i think thats also just as important, cus that flexes and causes the ring and pinion gear teeth to break.
heres one i found for cheap
http://cgi.ebay.com/T-MAXX-2-5-3-3-E...QQcmdZViewItem

[lincpimp]

Originally Posted by George16

It's the flex of the plastic cups in addition to the flimsy 2mm screws that won't stand the power of brushless setups.

I'm running UE ultralite with 8 spiders on my diffs and they stand the power of the 1515 1Y on 6S.

If you don't want to spend a lot, just get the FLM or Nova-RC alum cup with 3mm screws.

Gotta drill out the stock ring gear if you go with a 3mm screw cup. $100 bucks a diff for the cups and the case sound like highway robbery. I could think of a better way to spend 200 bucks, myself. Or are you only going to do the rear diff?

[George16]

Like Linc said, you still have to drill the ring gear t o accept 3mm screws. I can tell you that it's a pain in the ass to drill them unless you have a drill press. Traxxas ring gears are made of hardened steel.

Yes, those are the Nova alum diffs.

Here's the FLM diff drilled out to use 3mm screws. No drilling required. You can get a pair for $60 plus shipping.

http://www.2coolrc.com/detail.aspx?ID=93

[blueb8llz]

i only need the rear. my fronts are holding quite well. wow. thanks for that link george! so that flm al cup will fit my 3905 correct? so do you guys still think ill need the al diff casing? i think i might as well get one, i think i read that, thats what causes the ring and pinion gear to break,because of the flexing of the plastic casing. the cheapest one i found was this one....you know if itll fit my 3905?
http://cgi.ebay.com/T-MAXX-2-5-3-3-E...QQcmdZViewItem
and this one:
http://www.2coolrc.com/detail.aspx?ID=382

will any of these fit my 3905 without any mods onto my stock traxxas parts such as the bulks, driveshafts, etc..
or do you guys have one that you wanna suggest me instead. the flm ones are $45 kinda pricey.

EDIT: after browsing around, those two are the only two AL cases i can find. i know the ebay one fits the 3905 , cus the seller said so. i would think the integy fits for the 3905 as well.
so now, which one would be more reliable?

[Just go Play]

Taking the time to properly shim your diffs will make them last a lot longer and costs little except the cost of the shims and your time. Aluminum cases may help but you still need to shim them if you want them to last.

[JERRY2KONE]

Originally Posted by Just go Play

Taking the time to properly shim your diffs will make them last a lot longer and costs little except the cost of the shims and your time. Aluminum cases may help but you still need to shim them if you want them to last.

That was going to be my line. You can buy all the best aluminum parts, but if the gears are not shimmed properly they will still eat each other in a very short time. Everyone looks to save a few bucks trying to go with the cheapest parts they can find. If you truly want bulletproof diffs as you first said in the thread opener, then get a good setup the first time and shim the gears properly. You will have more time playing instead of rebuilding, rebuilding, & oh yea rebuilding. Personally I would go for the FLM hybrid diff cases, and put the Hot Boddy hardened gears inside, with an FLM aluminum cup. I believe that Mike sells all of this here in RCM.

[George16]

Here's my reply to your email. Might as well post it here so other people can benefit from the info.

Ray,
Thanks for the kind words. Yes I’m using ultralite cases and ofna Hyper 7 diff on one of my trucks. The gmaxx uses ultralite cases with ofna 8 spider diffs (stronger than the 6 spiders). There will be no mods needed to fit them.

Here’s the link for UE’s Ultralite cases:
http://www.unlimitedengineering.com/...ore/13551.html

You’ll need 2 of these. You’ll need shims for use with the Ofna Hyper 7 diffs.

8x10mm in varying thickness (.05mm, .1mm, .2mm)
6x8mm in varying thickness (.05mm, .1mm, .2mm)
4x6mm in varying thickness (.05mm, .1mm, .2mm)

Bearings you need:
8x16x5mm (8)

You need rcmonster coupler (2)

For the diff output shaft, you can either buy those from RCmonster or make them like I did. You need the revo stub axles. Just cut the threaded portion off. That’s what Mike basically did. A pair of Revo stub axles costs $4.79 at Tower so you need 2 pairs.

http://www3.towerhobbies.com/cgi-bin...?&I=LXHFY7&P=7

Here are the Ofna Hyper 7 diffs. You can see the diff outputs I made in the foreground.


If you dont want to buy the coupler, you can drill the plastic yoke to 8mm like I did here:

But you also need to drill a 2.5mm hole on the pinion shaft so you can use the stock setscrew.

Here's what it looks like on the UE ultralite case:




GA 7075T6 bulks and UE ultralite cases:


I only recommend things I have personal experiences knowing that it will work . I researched all this stuff last year.

Here's the 8 spider diff and UE Ultralite cases I'm using on the Gmaxx:




Lito

[tc3_racer_001]

wow. they look pretty damn strong. can u get the 8 spiders for hyper 8 buggies? how much are they? ive got the 4 gear ones at the moment (LHS guy made a bet that i couldnt break the stock diff and if i did he would replace it with a better one...

im afraid wheeling down the street may cause them to break and they just look so sexy!