What's a Good Replacement Rear Diff for the E-Maxx?
 

Stripped yet another 3.3 model diff, starting to look into stronger diffs, any recommendations?

I'm low on cash... =/

Maybe some LST diffs modded in....

=/

something like this:
http://cgi.ebay.com/Team-Losi-Afters...lenotsupported

Eh, modded as in..... I have stock bulks.

A 3905 emaxx diff is the strongest available that will drop in. Other options are the lst diffs and the hybrid bulks for 1/8 diffs. Or try to find some ue ultralite cases...

hmmmm I guess that's the way to go.

3.3 diffs...
What should I upgrade, inside the 3905, to make it as strong as possible, without completely overkilling it, or raising the bill to so high, I can only dream? :p

A 20 dollar 3905 diff from ebay is about as cheap as you can go. from what I can tell getting an al case for the 3905 diff is most likely the next best bet, as it will keep the ring and pinion from moving due to case flex. The 3905 diff internals look to be pretty robust, but you can always get the flm cups. Not too sure if flm make a case yet, but golden horizons do, if memory serves me correctly.

Next is the lst diff swap, but you have to change both and it will cost at least 100 bucks in parts.

Oh then, screw that LST :p

I love being cheap.

So, just pick up the cheapest aluminum case or is that bad too?
Any recommended.. cheap case?

No much choice, but I have never bought one so there may be more available now.

FLM51500 is the 3905 diff cup, they do not seem to list a case. You can also get the cup with gears, FLM51000, that can take m3 thread screws which is a good idea. Still costs 32 bucks, but if you need new ring and pinion that along with 5382x will upgrade you to a solid new emaxx style diff

Hmm, I'll be checking fleabay.
Hows this?
http://cgi.ebay.com/GEAR-BOX-x4_W0QQ...lenotsupported

Says it's compatible with the 4909 only (TMaxx) and not the 4908....
Que!?

i have rd aluminum cases and cups on my brushless revo platinum and i havent been able to brake a diff with my 1515 2.5D on 5 cell lipo

LINK!

I like that..

http://monster.traxxas.com/showthread.php?t=460119

Says that he's rating the RDLogics (If that's what RD means..) a 3...
Gah?

Heres a link to the cases that accept the 3905 diffs: http://www.ghhobby.com/proddetail.php?prod=2584

Hmm, sounds good.
So I could just buy a set at a time, as my front diff hasn't busted a diff yet... *knock on wood*.


What diff oil do you recommend?

EDIT1:
Anyone have any experience with these?

Looking at the various threads, they seem to lack the info that the 3905 maxx diffs are superior in design to the 3.3 and previous diffs. They have steel inserts to keep the spider/output gears in alignment. The al diff cups mainly help by not flexing, and the flm with the 3mm bolts and modded ring gears will handle more abuse than the stock 2.8?mm bolts and plastic cups will. The cups will not help the ring and pinion gears survive. Al cases will help them survive better, as the al does not flex like the plastic stock cases do, which alters the ring and pinion mesh.

So if I was to do this I would go with the flm cup with the modded ring gear, and the golden horizons diff cases. You can do the rear first as it takes more abuse, unless you jump alot, then the front can take some abuse during landings.

So about 25 shipped for one case and around 35 bucks for the flm cup/gears. And about 15 bucks for the 3905 specific internals. 75 bucks for 1 diff... Makes the lstd diffs cheaper, if you plan to do both (as the lst ratios are different to the traxxas ratio so you have to swap both).

So you all are starting to see why I went to the lst... Diffs are stout stock, no need to fool around like this.

Of course my 3905/E-Revo diffs have held up to 6s abuse quite well. If your cheap just try that first. I had issues previously with 3.3 diffs but these others in my maxx and e-revo have been great. If I start to have problems I will just go straight to the LST2 diffs and skip the others.

Hmm, I originally went the 3.3/3905 diffs, and I believe that is the one that is busted.

I guess if I adjust the slipper more, would it be more "gentle" on the diff? Or am I on the wrong track?

Do you mean new 3.3tmaxx, or old 3.3 tmaxx? The old 3.3 diffs are not as good as the 3905 diffs.

Slackening the slipper off would make life easier on the diffs, but, too loose and the slipper will melt...

Did you shim the diffs at all? Are all the bearings good, espeically the ones that support the ring gear/diff itself? I've put 3906/old 3.3-2.5 diffs through he'll with no problems when they are shimmed, even with plastic 3.3 cases. You only have to shim the pinion, but the driveshaft or cup must be attached. Why, any cup or shaft that uses the stock style drive pin helps determine the pinion depth, even some with grub screws do as well if they line up with the hole in the pinion. You can pm me for further explanation or if you'd like the hardly used pair of Integy cases with perfectly shimmed 3.3 gears/bearings I have no use for :lol: I know what everyone says about integy, but I have no complaints with these cases.

Hmm, I guess it's time to use those shims then..

PM Sent Overdriven.

So on eBay, what should I be looking for, just regular 3.3 diffs?

If you're going the eBay route look for 3905 emaxx or 4908 tmaxx diffs. These models are said to be stronger, and are also sealed units like the revo. All 3.3 models have the 4 screw plastic diff cases so you can't tell that way. Best is to ask what model they were pulled from if they don't list the model number. Btw a pm will be there in a few minutes.

Not the 4909?

Great, waiting for the reply.

Nope, not the 4909. The 4909 got the Revo driveshafts and sealed pivot balls, and 4 screw diff cases, but not the Revo style sealed diffs.

The ones you want are the 4908 (and 3905 E-maxx) which have the Revo style Sealed diffs, which are in different housings due to the different size bearings used.

What about a rear spool?
So it should be a solid axle, right? Or am I thinking of something else...
Either way, is this a good or bad idea?

I don't race, just into bashing really.

The problem with spools is that for anything but off road it will give you issues. It is much harder on your drive train and drastically reduces turning radius. I have run with a spool and also used to use a positrac setup and much prefer tuning the diff action with diff oil. The other thing you may not realize is that with a spool you only get rid of the spider gears but still retain the ring and pinion. No way around that really.

To revive an old thread...
Would this work guys?
Revo 3.3 Spec diffs = the same thing as this link?
http://cgi.ebay.com/NEW-TRAXXAS-TMAX...lenotsupported

No not necessarly. We were upgrading to Revo 3.3 specs before traxxas came out with the improved 3905 diffs. Take a look at these couple of links. The difference between the old ones and these are the metal pieces beef the differential up and make it more solid.

THis is the cup which is also has a seal, the metal side plates and takes a 2.5mm screw instead of a 2mm. The 3.3 specs don't
http://www3.towerhobbies.com/cgi-bin...?&I=LXTKN0&P=7

In this link the addition that the older diff don't have is on the left with the three holes in it. The diff Carrier Support I guess is what it is called.
http://www3.towerhobbies.com/cgi-bin...FVSEARCH=5382x

This is the ring and pinion gear to go with the other items. It's from the revo but also used on the newer emaxx. Major different is the size of holes is for a 2.5mm screw instead of 2mm.

http://www3.towerhobbies.com/cgi-bin...?&I=LXNZW6&P=M



If you are buying a set off of ebay make sure the differentials are the ones that were removed from the 16.8v e-maxx 3905

THe 4908 T-Maxx and 3905 E-Maxx have the revo spec diffs and should be the strongest. Its very hard to tell the difference from the outside of the case and the seller doesn't list the model # of the donor truck. However the seller's other items are all from a 4908 T-Maxx, but I'd ask him if they are or not to make sure. Don't assume anything

Here a set of aluminum cups already setup. Doubt they have the improved internal gears of the 3905 but they are an considerable improvement over stock. I ran a similar setup in my FLM maxx without any issues for some time.

http://cgi.ebay.com/ws/eBayISAPI.dll...m=120429907461

I'd guess the final price might end up close to be double of what the current bid is right now.


Is the 4908 T-maxx the improved on they put out after the 16.8 e-maxx? Makes sense they use the same beefed up diffs.

Thanks for the lesson Gee, and here I thought I knew just about everything about traxxas monsters. I was just looking over the exploded views and noticed the 3905 has the e-revo spec diffs with the I-bar carrier support you mentioned, the 4908 T-maxx does not. Although the outer cases, bearings, ring+pinion are the same and both use 2.5mm diff cup screws.

BTW I still have those Alum cased diffs all shimmed ready to go

BTW I still have those Alum cased diffs all shimmed ready to go[/QUOTE]

the outer casing is alum too? or just the diff cup? does it have the 3mm screws too? is it the 3905 internal diffs.
how much you selling them for?

pm sent

So I should be looking for TMaxx 4908, or EMaxx 3905 diffs, right?

Those are some neat diffs Gee, but, damn, that's a lot of money I can't deal with... right now.
But hmm, I will be getting about some cash flow in pretty soon, how much would you bid for that?

Like, the max, you would lay down for those two diffs:
http://cgi.ebay.com/ws/eBayISAPI.dll...lenotsupported

you should ask the seller if they are shimmed. even with the al diff cup, it can still break without a shimmed diff.
too bad it didnt come with al casing.

Your in the same boat as the most of us were at one time. Tearing into the diffs once a week to replace a blown diff or beveled gear. Kept doing it due to the cost of the upgrae and the stock gears were cheap. That got old fast and so did we. Not old but fast at replacing the diffs. How many of you guys out there timed how long it took you to get a diff fixed on the maxx? Was lightning fast compared to the first 2 hour differential. I was doing them in my sleep. JK I was doing them too often though, running masher 40's and endos to flip the truck forward.

I didn't have much of a problem with the internal gears once I went with the aluminum cups. Still ran into an occasional beveled gear problem though. Shimming and setting the brakes so they don't lock up on asphalt helped with that problem. It's been a long time and a lot of other differentials and parts since then. I have 35.00 a piece stuck in my head for what they cost back then. The cups were close to 20 each, the internal gear weren't anything special but you needed a ring gear that accepted the 3mm screws. That left you with the Robinson Racing ring and pinion. Which is where the other 15.00 comes into play. I was watching to see what that auction went for so I had an idea what these ones might go for.

http://i212.photobucket.com/albums/c...emaxxdiff3.jpg

Your not drooling or humping the screen are you rawfuls? I know how attractive these must look to you right now. I almost didn't post the picture but hell I couldn't resist it. First it's wow, I'd sale my soul for a set of those, then a bit of envy flows throught the viens, after that you end up a bit pissed when you realize that I'm not the only rcm brother you have that has just got these laying around with no use for them. Don't try being nice to me now. I will know what your up too. But don't worry plans have been set into motion for you. More on that later, back to rambling now...

Where was I..... End up going through differential so often you have plenty of spare parts. Enough to have working diffs just waiting to be dropped in when a problem would occur. Instead off having down time, just drop in a working one and fix the other later. Some how those two worked thier way out of the rotation.

I modified an existing ring gear to accept the larger screws on one of them. I used graphit powder to lube that one and packed the other with grease. The graphit does the job just fine and is not the mess like the grease is. Doesn't break down either. One has the RRP ring and beveled pinion.

Sorry for rambling, got a case of the happy fingers, been typing it up all over the net tonight. I've got to remember that it doesn't matter how long your post is. It still only counts as one post. lol

Okay back to your differential envy problem rawfuls. I talked to the boss and he thinks we might be able to put you a payment plan if your interested. Will just want to make sure you fit the profile we are looking for. If your debit to income ratio falls into a catagory that your are likely to default or be late on a payment, then your in. That give us a customer for life and you an opprotunity to a line of useless credit with us for the rest of your life. Once we bump the interest rate over 30% for a late payment. Your credit line will soon me maxxed and every payment you make will be almost all toward the interest and your credit card will become useless except for scrapping ice off your windshield. Don't know what the college student in Florida use them for, but that's what the majority of college students are using them for up here.

Oh, one other minor thing. We'll need some info about your first born, if it hasn't happened yet all the better. :diablo:

Seriously, send me a pm and I will see if I can help you out.

Aluminum cases and shimmed gears help a ton. With the new I-Beam diffs in aluminum cases (aluminum cups can help, but definitely get the cases) you shouldn't have a problem with them. Most Ring/Pinion strippage is because of the stock plastic cases which flexes under power which throws off your mesh and screws your gears over. Aluminum cases don't flex under power nearly as easily.

I think the LST (or perhaps Muggy) diff mod is the best way to get bulletproof diffs on the cheap, with the aluminum cases those things are tough as hell! I'd like to see Ofna Spider diffs in a Revo though (pretty sure the 8 spider UE diffs are rebadged Ofna diffs but I'm not totally sure).

I really would like to go see the LST mod, but, eek.
I'd need new bulks as well, wouldn't I?

---

Gee:
HEY BEST FRIEND!

Geez, is that a PM in your box? Hmmm :whistle:

So the seller of these:
http://cgi.ebay.com/ws/eBayISAPI.dll...:X:RTQ:US:1123

Says they're pulled from the new, extended, TMaxx 4909, are these the ones I want?

Overdrive said the t maxx diffs do not have the cross bar like the 16.8v emaxx does. I just looked also at the newer 4908 & 4909 models and none of the tmaxx exploded view show the cross bar in the diagrams or have the 16.8v differential carrier listed as the part to use.

Your best bet is to stay away form any diff that is not advertised as the 3905 16.8v emaxx differential. The seller will know what he/she has and specifically indicate it is a 16.8v differential instead of a 2.5, 3,3 fit all differntial type listing.