SAVAGEry

Hi, again..


Got center diff some months ago, but the diffs keeps on crackin'. Using very thin oil in da center diff... it barely accelerate... ive replaced all my bearings.
Has anyone tryed the new rear bulkhead, the same part# just with an additional "X"?


¨No-one else having this problem?

Im now running 3s LiPo, but with the center diff it's slow at accelerating... I guess the only thing that Ihave not replaced /Checked (in/ aboutthe drivetrain) are the bulkheads.


and im sorry for my broken english.

SAVAGEry

now...


which tires do you use for it?(you who don't strip any gears)

gforce2448

My Feedback: (12)

I have not stripped any diff or center diff gears. I have had my Mini Revo for quite some time now. I was running Nimh batteries and switched to 2S lipo recently. I was running Proline Dirt Hawg tires with Titus Beadlocks, but the extra weight and hard landings caused my chassis to break and rear housing to crack. I replaced those and went away from the heavier tire/wheel combo. I still wanted an oversized tire so I have gone to the Traxxas dished wheels made for the Mini Revo. Which any type of 2.2 rear buggy tire can be used with them.

dacaur

Im still running mine stock, only thing I have changed is the body and I used 2 of the stock NImh's in parallel. I'm not easy on it, but not issues with the diffs at all....

For the one who keeps breaking them, whats your setup other than 3s lipo? You are using the "speed" pinion, right?

SAVAGEry

I use Speed pinion, centerdiff (with lithium grease=thingrease), Stock motor, but I may replace my bulkheads... with the new ones from Traxxas and see if that helps

dacaur

Well, the only other thing I can think of then is stop running into things.... 3 cells might just be too much for your driving style... You using stock wheels/tires?

SAVAGEry

That may be.
I'll be getting a 2s LiPo from hobbyking. That + new bulkheads. and Isoo wanna remove the centerdiff... Ihate the way the car handles now...or maybe I'llgetsome thicker oil...

Thanks.

SAVAGEry

lol.. Iguess Ishould try it on 7,2 volts first, as Ialready have got one of those...

spoock

Hi

Have you tried the bulkheads with the "X" in the traxxas code?
Did it works better then stock bulkheads?

Thanks

cooldriver385

I think I screwed up my rear diff too. I opened it up and there was this black dusty stuff. Some of it looked like it was between the metal teeth of the ring gear. Do I need a new ring gear/pinion? And what's with all this talk about diff fluid?

dacaur

black dusty stuff? not sure, metal dust maybe? if its still working ok, dont worry about it. as for the fluid, the differential should be filled with diff fluid. thats the part attached to the ring gear. that the outdrives attach to.

cooldriver385

Well when it's opened up the ring gear and pinion mesh alright, but not completely free. Then when I put everything back together, I try to spin the shaft, and the ring and pinion don't move at all. The thing is, is that even when it's all opened up, they don't mesh and spin nice and free.

dacaur

hmm, so it wasnt working and thats why you opend it? Need more info... the black dust could also be plastic... is it magnetic? that will tell if its metal or plastic... I would check the bearings, they may be seized.

cooldriver385

I opened it up because when I was driving I would hear a grinding noise and when I let off the throttle it would come to an abrupt stop instead of coasting. Something was sticking. So I knew there was something wrong. Everything was fine, then the input shaft for the rear differential wouldn't freely move. Opened that up and there was black stuff. I called Traxxas and they said I might need a new diff set. He said that black stuff might be hardening grease, but how does grease harden? The output shafts that are connected to the wheels spin freely in opposite direction of each other, so I think the differential itself is fine. But it's the ring gear and pinion that aren't meshing correctly, I think. And seized bearing? As in the rubber-sealed ball bearings? How do those seize? The black dust is not magnetic.

dacaur

If its not magnetic, this its probably grease. I have not cracked mine open yes so cant really help much, but if nothing looks melted, its 99% probably just grease... Rubber sealed bearings are not immune to going bad, just more resistant. If you have ever driven it through water, you have a chance of a bearing going bad. it could have a defect in the rubber seal, or the seal could have been damaged during assembly. there is also a VERY slim the chance the bearing didn't get any grease at the factory, in which case it wouldn't even need water to go bad...

There are two bearings on the pinion shaft, one inside the diff case, the other outside. Take them out and see if they spin freely. if not, replace them. From your description, it sounds like thats the problem.

cooldriver385

I solved it. There was some grease that I guess hardened in some spots so the ring and pinion couldn't mesh and would get stuck. Good to go now! By the way I haven't driven it through water or mud or anything.

The cracked egg

i just stripped my ring gear does anyone know about stronger ones

The cracked egg

its all on how u drive i striped my ring and spur within a mounth of driving it

The cracked egg

put it in serize ull rip ur diffs up like me

dacaur

Yea, I'm really happy with the performance in parallel... I couldn't even imagine how insane it must be in series!!! No thanks... as it is on the stock voltage I sometimes put it in "training mode" when driving on rough terrain so i flip it less and get longer run time

NitroNuisance

I got a mini slash I've ben running on 3s for about a month and it runs fine but it might be clicking a little. Idk if this is just in my head after reading about the problems and the new updated diffs or if they are really going bad. Either way I'm gonna see if traxxas will send me a a set of the new ones and if not I'll buy a set for when min give out. I have heard shimming the difs is suppose to help. Is this required on the new ones too? Can anybody show pics or a link on how to do this? I know how to drive a high powered rc and don't beat on mine but I have noticed 1 other weak spot and that is the axle carriers. The stupid littl clip in ball caps are crap. I broke 3 out of the 4 in a single quadruple rollover. I upgraded to the rpm ones and that took care of that. I've also read that the t-bone is suppose to strengthen the chasis so I'll be getting one of those.

dacaur

That weird, I have rolled, tumbled, and cartwheeled mine hundreds of times and never had anything but a a-arm break, and that wasnt from a roll, it was from going fomr 3-mph to a dead stop due to a pointed rock embedded in the dirt....

I have not heard of a new R&P set, when did that happen?

NitroNuisance

Have u taken the wheels off and inspected them lately? 2 of the 3 that were cracked weren't completely broken apart yet. If there's excess slop in the wheels I'd check because it is definately a weak point. The rpm ones are lighter, stronger, and actually have screws holding the pivot ball caps on. I talked to traxxas support today and they are sending me the updated bulkheads for free. Not sure what u mean by r&p but if ur talking about the bulkheads yes they fixed the problem on the new ones. They added a screw that crosses the 2 halfes and hods them tighter eliminating some of the slop that the old ones have. the part numbers are the same but there's an x at the end. That's how u can tell if u have the new ones or the old ones. If u have the 2.4ghz vxl merve u probably already have the new ones but I don't think the slashes have them until they release the 2.4ghz version of those. I have the vxl slash and I got the old ones.

larryjgarner

hello,,i too have had major trouble with ring/pinion gears with this truck,i have gone through 7 or so sets in three months,,shimmed diffs,new bearings,,same thing,,to me,it looks like there are a few reasons for this issue,,one is the fact that the rear case that was on my truck when i overpayed for it,would never line up when out of the truck,two-it looks like when the motor engages the center drives and starts to work that rear pinion,it looks like there is much sideplay from the tork,i used a shim to pull that pinion closer to the diff case to take some play out and this worked and everything still spun freely,,one shim on the pinion,and two on the diff itself yeiled the best results so far,,,i too see the "black stuff" in my rear case,,this is grease and diff fluid binding with the dirt that snakes its way through the cracks and stuff on these things,,,i tried some RTV  sealant around the bottom half of the assembled diff case before i put on rear arms and skid plate etcetc and used a pair of vise grips to hold it together until it dried,,not to tight though,,this seemed to do the job half way,,,then on the dissasembley after that i noticed there was less dirt but it still was letting dirt in from the top of the case,so something around the case to seal it up might work,,idk..,,but that is about the only nagging problems with this truck,,,also these ring gears seem to be off center,it seems,anyone else notice tight spots,,also i have seen the integy aluminum diff case and was wondering if any1 has tried it,,it looks as though it might be a better made product with tighter tolerences than the stocker,,the quality on these rear diff cases are bad it sounds like,..and a $50 dollar diff case is crazy but so is buying gears all the time,,,,still like my inferno st-r better,,,,nothing leaks,binds,strips,squeeks or cracks,cou[le squeeks,,,but thats after driving it for over 5-6 years atleast 3-days a week,,HARD,,

dacaur

out of curiosity, what voltage are you running, and on what terrain?