xxxcr diff barking

[harryg]

hi folks, please help very disappointed, my xxxcr diff began barking when racing in mansfield last night, got home stripped and cleaned everything, clear grease applied and put back together, ran on my drive for 3-4 minutes when it started barking again? tightened up again ok but why does it come loose? it sounds like a bag of broken marbles-very metallic! if the diff is knackered what parts are actually knackered as i cannot fathom what breaks down? please help as my faith in the xxxcr is diminishing rapidly, I must persevere for all my mates use b4's are cannot bare the hideous remarks of my xxx or my inability to run consistently Thanks in advance. h

[big air]

Have tried taken in to the vets

If its working loose the diff bolt nut is knackered, new balls and diff plates time
as the balls might not be round no more

hth

[Fiddybux]

Right then. CR diffs are great as long as you treat them right, as are all Losi diffs IMHO. And I know what you mean about all the Associated yobs giving you hell!

First, load up the diff with absolutely tons of grease. When you think there is enough in there, put more in. If you don't want to use expensive diff grease, then just use standard petroleum jelly (Vasolene). It really makes naff all difference if you ask me because of the quantities you put in there.

Then, assuming all your diff rings and shims are okay, tighten it up really tight. Not so that it locks, but nearly. You shouldn't be able to spin it all at all by hand using drivers in each outdrive to lock it. Or you can use a diff tightness gauge thingy instead of the drivers...but I just use the drivers. I have broken drivers doing this though, so use an old one or a thick one.

You should only really be able to spin the diff when it is installed using the wheel / CVD / dog bones to add torque.

Put some threadlock on the screw if you have to, but you shouldn't need this if you use a new or new-ish nylon threaded nut on the other end of the screw. If yours is old this could be the reason it is coming loose.

If the diff is new, then it will loosen a little as it beds in, so its worth checking after every run to make sure it is tight enough.

Hope this helps.

[super__dan]

Interestingly I couldn't disagree with you more on some of those points

[Danny McGee]

Im my opinion. It sounds like the doff just needs a rebuild with the new bits below;

Diff plates
Thrust race
possibily the balls too.

I very rarely have any problems with my diff and they usually last at least half a season before they need some tlc. Here's what i do (all new bits)

put a bit of grease (losi clear) in each of the holes for the diff balls, then pop the balls in using a pair of tweezers so not to get any other greases on them. Then i build up the trust race using the greyy/brown grease that comes with the kits. I put some on both the lower and the upper thrust plate but not a massive amount.

If you have the cr diff i also put some of that grease on the bronze rings as it helps it not slip.

I then bang it all together, possible adding a little bit more grease in the main gear (i dont put shed loads in though as its pointless) Then tightern it all up using a flat bladed screwdriver. I dont do it up tight at this point. Give it a few turns to make sure the grease is covering all the bits inside then tightern it up a bit more. I then install it in the car and set the diff by holding the slipper and making sure that the slipper "slips" first and not the diff. If its a new install you will need to crank it a little bit after the first run probably.

I think thats about it

Anything else feel free to ask

Danny

[super__dan]

Worryingly I agree with nearly everything Danny has to say.

My main points are do use the correct greases, don't put too much on as it will only 'attract' and hold dirt in the diff. Also I completely agree about turning the dif by hand to bed in, then gradually tightening.

[Chris Doughty]

do you not diff it out to bed in the diff Danny?

quarter throttle and hold each wheel for 30 seconds each side, and then set the diff?

[migsy]

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ann summers have now stocked up on the latest vasoline and are exspected to sell out due to the build craze of rc cars.

RC world we solute you. LOL

[Lee]

Originally Posted by DoughtyUK.net

do you not diff it out to bed in the diff Danny?

quarter throttle and hold each wheel for 30 seconds each side, and then set the diff?

I do this, funnily it was another CD who taught me to do this many moons ago whilst racing on road.

[Chris Doughty]

MF of Losi XXX-T MF2 fame taught me. it makes a lot of sense if you think about it.

[Lee]

Craig told be too when i was melting plastic rear diffs in the tc3, they were like a spool when they heated up, which actually made on road more fun

[Southwell]

Originally Posted by DoughtyUK.net

do you not diff it out to bed in the diff Danny?

quarter throttle and hold each wheel for 30 seconds each side, and then set the diff?

I do it with new builds/new internals as it beds in the plates, then i set it.

[Stu]

Originally Posted by Fiddybux

Right then. CR diffs are great as long as you tr................................................ .................................................. .................................................. .................................................. .................................................. .......sen a little as it beds in, so its worth checking after every run to make sure it is tight enough.

Hope this helps.

Originally Posted by super__dan

Interestingly I couldn't disagree with you more on some of those points

That's another 'Dan-post' where I can actually hear your voice in my head as I read the words -
More people should make a point of starting more sentences with world like, interestingly, worryingly, actually, or such like - in the style of a Dan.

[Lee]

Amazingly, i also read Dans posts with a little Dan voice in my head, the same with Yardy, i always visualize him telling me the story and getting very excited doing so.

[super__dan]

Ace

[Northy]

Danneth, the gentleman (and a little bit posh) racer of toy cars

Interestingly I too read his posts with his voice in my head, but I like it when he uses words like 'gash'

G

[Southwell]

Woof.

[ashleyb4]

Interstingly, another thing to check is that you have the internal diff bearings seated correctly my diff barked and after about 5 diff rebuilds with new outdrives gears balls thrust race screws etc i found this to be my problem.

I hear the people read there posts out most of the time its stu and charlie fraiser.

A

[ben]

Originally Posted by ashleyb4

Interstingly,
A

Ash if your gonna make a joke, atleast spell it right.

[ben]

Originally Posted by Lee

i always visualize him telling me the story and getting very excited doing so.

Do you get a semi-on?