Hippopotosaurus Posted July 24, 2014 Share Posted July 24, 2014 I bought the kit version of the axial exo terra just over a year ago and after I'd built it, it all seemed to be running fine. However, recently, upon braking there was a horrible grinding noise- thanks to a different thread I realised it must be one of the diffs and sure enough, upon taking the front end apart I found a load of metal shavings in the front diff housing which had come from the crown gear- although it won't show up in a photo very well, one side of each of the teeth had been worn down to an angle that must have meant the pinion and crown gears slipped past each other when put under stress, like braking, creating the grinding noise. Obviously I'm going to need a new crown gear (the pinion seems fine when compared to the identical rear diff pinion, although they come together anyway...). However, when browsing modelsports website for a replacement I noticed you can get an upgraded crown/pinion but I can't see the difference (other than gear ratios) between that and the standard crown/pinion as both are heavy duty and cost around the same? Here are the links: Standard- http://www.modelsport.co.uk/axial-heavy-duty-bevel-gear-set-36t-14t/rc-car-products/370997 Upgrade- http://www.modelsport.co.uk/axial-scorpian-heavy-duty-bevel-gear-38t/rc-car-products/30067 So I was wondering which one would be best for me to get to prevent this happening again and also what gear ratio would get the best speed out of my kit (I'm running a castle sidewinder combo with 3800kv motor on 2s) although if I get the upgrade there is only 1 ratio to choose from Also does anyone have any other tips on how to stop this happening in the future- the only other thing I can think of is to tinker with the esc settings and hope there's an option to set up the braking to be slightly less aggressive (I can't do this until the weekend though because I have the castle link programming kit instead of the programming card but I don't have my laptop with me like an idiot lol) Thanks for reading- any advice is helpful Quote Link to comment Share on other sites More sharing options...
hebby Posted July 24, 2014 Share Posted July 24, 2014 (edited) First up you will have problems buying them from the links as there out of stock Second, buy a few because this will not be your last time replacing them Third, Try some shims to keep the diff in place as you will find lots of movement LOTS! i had the exact same problem and almost every second run needed a new diff. did i stop the problem? Nope! but i did find an intresting read why people speculated that axial stopped selling the kit version and every one pointed to the poor plastic used on the kit and since released the RTR version in the end i split my EXO into bits and sold for spares and if i remember rightly some other person had trouble finding the diff gears and ended up buying both my front and rear gears that had never been run just fitted and then left. would i buy another exo? yeah but not from a kit version Edited July 24, 2014 by hebby Quote Link to comment Share on other sites More sharing options...
Hippopotosaurus Posted July 24, 2014 Author Share Posted July 24, 2014 Funny how you find these things out having spent Quote Link to comment Share on other sites More sharing options...
hebby Posted July 24, 2014 Share Posted July 24, 2014 nope was on both diffs and less greese will be worse Quote Link to comment Share on other sites More sharing options...
Hippopotosaurus Posted July 24, 2014 Author Share Posted July 24, 2014 Ok thanks Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
ghazghul Posted July 24, 2014 Share Posted July 24, 2014 The HD gears are stronger (try drilling one!) and also spiral cut which should mean they engage better but have less tolerance for being out of line so need to be shimmed properly if they don't sit right straight away. RC-GO on eBay (taiwan) has them at a price that is tempting me to import some my my current crawler build. A well shimmed diff. should cope with anything you can chuck at it ESC / motor wise... my heavy crawler copes with full throttle to reverse on big grippy 2.2s and snaps CVDs / dogbones. But if the housing for the diff is warped / flexible then you will never get them to mesh nicely and they may move about under power, I'm not sure what the EXO housing is like but worth checking it for wear etc. Finally check all the bearings as a dead / wonky / badly seated bearing will ruin the mesh. Quote Link to comment Share on other sites More sharing options...
hebby Posted July 24, 2014 Share Posted July 24, 2014 (edited) the housing on the diff cases is made of rubbish plastic Edited July 24, 2014 by hebby Quote Link to comment Share on other sites More sharing options...
danb1974 Posted July 24, 2014 Share Posted July 24, 2014 IIRC there are some HPI gears that fit axial diffs As for going 2wd, yes you have to lock central diff and I expect you will start breaking the rear diff Quote Link to comment Share on other sites More sharing options...
Hippopotosaurus Posted July 24, 2014 Author Share Posted July 24, 2014 Hebby, you say you would buy the rtr version over the kit, presumably because they don't have the problem with the diff, but if this is the case then surely you could just buy the diff housing that is advertised as spares for the rtr and replace the ones that came with the kit? Otherwise I can't see why the kit version would have this problem and the rtr version doesn't? Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Hippopotosaurus Posted July 24, 2014 Author Share Posted July 24, 2014 And ghazghul- can you put a link to those hd gears, I can't seem to find them :/ Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
ghazghul Posted July 25, 2014 Share Posted July 25, 2014 And ghazghul- can you put a link to those hd gears, I can't seem to find them :/ Sent from my iPhone using Tapatalk Normally I wouldn't but as MS are out of stock : http://www.ebay.co.uk/itm/131085102593 You can get upgrade diff bodies (http://gcmracing.ca look shiny) but I am guessing it's the outer pieces that clamp the bearings in place that are weak... which has got to be a pain as the whole front / rear end bolt to them so plenty of forces going through. Quote Link to comment Share on other sites More sharing options...
Hippopotosaurus Posted July 25, 2014 Author Share Posted July 25, 2014 so whilst looking for upgrades that could help me out on this found this great website: http://www.asiatees.com with loads of nice upgrades for the exo and not too bad a p&p cost, what I was really interested in though was this: http://www.asiatees.com/display?id=56397&brand=Axial&model=EXO , an all aluminium front/rear bulkhead- do you guys think this coupled with the gcm diff bodies and of course a new crown gear will solve the problem- all aluminium reducing the play? I'm also looking at some aluminium chassis supports (front and rear) too, which would make the whole setup even more rigid Sent from my iPad using Tapatalk Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.