Unlock rear diff

[joerc2013]

Can anyone help me with part list to unlock the rear diff? I like to make it corner better.

[cruz1383]

i dont know but maybe just maybe a exo terra diff might work. dont knw for sure though as most axial owners dont really like unlocking anything lol its more of how do i lock this or that..

[altd896]

Same parts, as per your manual, as the front.
If you don't have your manual the instructions are on the axial web site.

[ark1t3kt]

Check out this thread. It's not as simple as putting the front diff into the rear.

how to unlock the axles in my wraith

[altd896]

Originally Posted by ark1t3kt

Check out this thread. It's not as simple as putting the front diff into the rear.

how to unlock the axles in my wraith

Rubbish
It's precisely as easy as fitting a set of the exact same spider gears/pin/orings to the diff cup in the rear as in the front & filling with diff fluid of your choice, on my 2.2 U4RC rig it's 1mill wt Mugen gel.
That post you linked says nothing different.

[ark1t3kt]

I stand corrected. For someone reason, I thought you had to modify the shafts to fit inside the diff. Like in the front, the outdrives are C clipped so they don't move. Sorry for any confusion.

[camperwill]

How do you go about filling the rear diff with fluid since it doesn't use the same sealed output shafts as the front?

[ark1t3kt]

Originally Posted by camperwill

How do you go about filling the rear diff with fluid since it doesn't use the same sealed output shafts as the front?

according to altd896 above, you would use the same rubber o-rings that go onto the front out drives.

[camperwill]

Originally Posted by ark1t3kt

according to altd896 above, you would use the same rubber o-rings that go onto the front out drives.

But this still doesn't seal anything since you would need to fill it prior to installing it and then slide the axles into place.

[ark1t3kt]

I agree, it's not that simple. That's why I questioned the advice in the first place (see post #4 above).

Take a look at this post, start reading at #82. Finally - a 1/10 trophy truck built in the axial yeti

EDIT: Take a look here as well. open diff rear end Same problem as you described, but with a workaround. Not ideal, but you can make it work.

[bee200sx]

Hey guys just wondering what oil would be a good starting point for unlocking the rear diff.

I hear some ppl using 500k but it sounds like that would pretty much lock it.

Anyways would be good to hear what you guys are using.

[camperwill]

500k still offers plenty of play. I had mine unlocked but both outer o-rings kept breaking due to how the rear axles sit, this caused all of the fluid to leak out after a couple of sessions.

[bee200sx]

Originally Posted by camperwill

500k still offers plenty of play. I had mine unlocked but both outer o-rings kept breaking due to how the rear axles sit, this caused all of the fluid to leak out after a couple of sessions.

Anyone had any success with unlocking the rear diff without it leaking?

[HDMM]

Originally Posted by camperwill

But this still doesn't seal anything since you would need to fill it prior to installing it and then slide the axles into place.

The only thing that gets "sealed" is the housing the spider gears and side gears are in, there are o-rings that go behind the side gears and seal the unit. Also a gasket between the ring gear and housing. It doesn't have to do with the axles, or axle housing.

Kinda like this;



While not a ideal design with the Axial straight axle because of the flats in in, it should work with thick enough diff fluid.

[camperwill]

Originally Posted by HDMM

The only thing that gets "sealed" is the housing the spider gears and side gears are in, there are o-rings that go behind the side gears and seal the unit. Also a gasket between the ring gear and housing. It has nothing to do with the axles, or axle housing.

When you put the diff back together you have a hole on each side gear where the rear axle slides into, this is unsealed until the axles are put into place. Based on the front diff each side of the diff housing has two o-rings, one that is internal and is placed under the side gear and one that is external. The force of the axles causes the external o-rings to break.

[HDMM]

Part of the sealing effect is the oring, washer and back side of the side gear. I can see where there would be a issue trying to stick it together with fluid coming out while your trying to stick the axle shafts in there. Unless there are side gears that are not machined all the way through, for this application.

I'm used the the gear diffs in Short Course trucks, the outdrives get pinned in there essentially sealing the diff. When I ran Durango, I had 3 assembled gear diffs with different weight fluids for different track conditions.

[HDMM]

Here's a pic of the SCX10 open gear diff, it anyone needs part numbers or anything.....

[ark1t3kt]

Originally Posted by HDMM

Here's a pic of the SCX10 open gear diff, it anyone needs part numbers or anything.....

What I find interesting is that the instructions call for you to grease the spider gears instead of using silicone diff fluid. This should eliminate the issues others have been having with the fluid leaking out after a few runs. Also, it only calls for 2 o-rings instead of 4, and both of them are inside the diff case.

Thanks for the info.

EDIT: How well will the grease work instead of silicone diff fluid? Would it still be "locked" if the grease is thick?

[RustyUs]

This is the exact same situation I've been trying to figure out all morning. The only possible way I can think of to fill the rear diff with oil is to have one axle inserted, and use some type of mini hose (or long enough syringe) to inject/fill diff housing from the other side.

My next option would be to possibly try some Bad Horsie Diff Locking Grease. Description says..."creating a limited-slip-like feel".

[altd896]

What weight diff fluid are you guys trying to use?
Cos the 1mill weight Mugen gel I have in mine doesn't run & you don't pour it, you scoop it, use a popstick or plastic knife. By all accounts from the guys here the ½mill is still a similar sticky gel.
The guys here are using either of the above 2 gel in their Yeti, mine is in the front axle of a U4RC 2.2 trophy rig but the axle goes together exact same as Yeti rear.
Green slimed o-rings & gasket same as doing shocks.
Assembled with the just o-ring under the spider gears, drop the bottom gear in the cup, scoop gel in till its all but full, sqeeze the cross shaft & side gears in, push the other spider in & used the axle shafts to keep the gears all aligned while I screwed the ring gear down, pulled the axles out, dropped the centre in the housing & put the axles back in.
Nothing comes out while the axles are out, takes barely a minute to pull axles, drop in centre & put axles back in, you can do the centre bearing caps after the axle is in.
Been through 2 u4 race days & its still in there.