Arrma differential rebuild

[Unusual RC]

Short update!
I opened my diff, which has never been opened by myself in 3 (!) years!

How did it look?

• extremely difficult to open, lit did not want to come off
• the silicon oil became black, thick goo. Almost like grease, which it is definitely not
• All gears show no wear or damage. All gears have their "teeth" (WRONG, see next message)
• most remarkable: the biggest conical shaped gears do not have a shimm at all!? (wrong again, they did have the narrow shimms, not visible under the thick dirty silicon oil)
• when put back, it works again. However you feel there is fine debris in the oil, if there is a bit of sand in it

When I have cleaned out the oil I will make pictures.

The absence of the shimm, which is the reason the later diffs of the same series failed, is quite a discovery.
This would mean the satelite gears must have different thickness in order to fit?

To be continued!

 

[Unusual RC]

Small update.

I was wrong concerning the gears.
Here you can see (if you look carefully, hard to see) a perfect half breach in one of the two small satellite gears

Because my car is already two years old, I have decided to completely rebuild the car...oh boy

 

[Unusual RC]

Small update.

I am doubting to create a new topic on this.
I rebuild my old diff.
I did replace all the rubber seals.
I kept the outdrives since they did wear a bit, but still are in good condition.
I do have all the the outdrives (both diff as wheel side) new as spare.

I have rebuild over four diffs now, so I should get a bit familiar with it.
Everything fitted nicely, until I closed the diff.
When I turn the diff both by the outdrives by hand, it feels very rigid. It can turn, but with a lot of constant resistance. Unlike my previous rebuilds with equal diffs and part numbers.

What I did not like was the metric screws to close the diff lit. The originals are non metric, but can be opened with a small torx bit.
The metric screws should be better. But the hexes break out way to easily. Very week metal.
Bummer, put back the original ones.

I put back the diff in the tranny, and put it back in the truck.
Still I have to rebuild the front end, as well as refill the shocks (minor) in order to do a full surface test.

The brushless sensored 8.5T combo works, and if you pull out the sensor cable it can operate as a brushless sensorless combo. So in case or damage it is not the last resort!
I will do a test to see the difference.

The diff feels not right. Thinking of disassemble everything again!

To be continued!

Diff maintenance kit, diff outdrives, wheel outdrives

Inserted the new rubber o-rings (red)

Black seal and satelite gears and washers in place

Filled with 7000cps silicon diff oil

 

[ajdragon]

Hi

The diff's are a hit and miss when it comes to rebuilding them. The qulity of the rebuild kits is way off the mark, I have 3 different diffs for my Raider XL BLX, the diff that came with it is in ok shape, the second diff I built with new parts was completely unusable, that is until I took the dremil to it, and the third one came from Arrma after I told them about all the problems I was having with the diff's, that one actually seems to be working good. So you may want to contact Arrma and see about getting a good working diff from them.

 

[Unusual RC]

Hi

The diff's are a hit and miss when it comes to rebuilding them. The qulity of the rebuild kits is way off the mark, I have 3 different diffs for my Raider XL BLX, the diff that came with it is in ok shape, the second diff I built with new parts was completely unusable, that is until I took the dremil to it, and the third one came from Arrma after I told them about all the problems I was having with the diff's, that one actually seems to be working good. So you may want to contact Arrma and see about getting a good working diff from them.

I have 3 Fury/Mojaves here, all 2013 model.
This diff is the oldest I have, and did last the longest off all.
This is also my third rebuilt kit (rebuild my brother in law's 2013 SPEC Fury a few weeks ago) I have done.

Did you use the new bolts?

Personally I do not think the rebuild kit is of poor or deviating quality. My personal suspect is the casted diff housing itself.
Diff tolerances should be tight, very tight. But not too tight.

i found my diff outdrive shim's (.1mm) yesterday, so I am getting it out anyway since there is some play.

To be continued...

 

[Steveoarrma517]

My bad, after working on shimming aluminum diff cup I have noticed that I have been installing pin side blocks into housing round end up.don't do this,we'll make you think gears are binding up.

 

[Steve]

I'm still amazed at how much better my Vorteks drives and the increase in traction all from adding 5000 diff oil.

Worked so great, I did the same to the Vorteks cousin car, my Raider.

 

[AceM]

The gear in the diff case has some type of wax on it, should we clean and put oil or some grease there

 

[AceM]

which type of grease should i put in the diff case on the 2 gears

 

[Steve]

which type of grease should i put in the diff case on the 2 gears

I believe @WoodiE rec'd on a thread long ago, can't recal when, using white lithium grease.
Hey Woodie, is my memory clear or cloudy on this?
Thanks!

 

[Raji]

I tried to climb over some big rocks and trees roots. but one of the front tires spins alone. If I add a thick Diff oil in the front do you guys think it will reduce that one tire spinning?

 

[WoodiE]

I believe @WoodiE rec'd on a thread long ago, can't recal when, using white lithium grease.
Hey Woodie, is my memory clear or cloudy on this?
Thanks!

Yup, for the gear teeth I've used white lithium grease with great results.

 

[AceM]

I found in another group to use mobil lithium grease so i got that

 

[Kraton_Kev]

I tried to climb over some big rocks and trees roots. but one of the front tires spins alone. If I add a thick Diff oil in the front do you guys think it will reduce that one tire spinning?

Yes. From what I hear, and have yet to try, is 250k center and 80k front/rear.

 

[Steve]

I tried to climb over some big rocks and trees roots. but one of the front tires spins alone. If I add a thick Diff oil in the front do you guys think it will reduce that one tire spinning?

My crawler buds said they have locked diffs.
When one wheel is in the air, they still have power and control.
A couple guys have the OJ Simpson Bronco from Traxxas, which has servos to lock and unlock the diffs on the fly.

 

[Matt74]

I am



No need for that sir, it has the right title if you read the text sir.

No harm here

With that said, we have a lot of Granite owners that think it is informative.

View attachment 7555

Have a superb evening

Hi Thomas,

You meantion at the start that you needed to cut the X-ray 355080 diff pins to fit the diff housing....

May I please ask how much you trimmed off each end and what you used to do it?...

 

[TpPartsRcXtreme]

Hi Thomas,

You meantion at the start that you needed to cut the X-ray 355080 diff pins to fit the diff housing....

May I please ask how much you trimmed off each end and what you used to do it?...

No i am so sorry buddy i do not ?. I eyeballed it, marked and cut, some small adjistments then to make it perf2vt

 

[Matt74]

No i am so sorry buddy i do not ?. I eyeballed it, marked and cut, some small adjistments then to make it perf2vt

No worries... guess I could use the stock one without the notch in it that comes with the diff maintenance set to get the right length... then try cut it with a Dremel and clean up any burred edges..

Cheers

 

[Niz55]

Nice. Very helpful video.

 

[cootertwo]

I just made 2 spools, the easy way. I had 2 new Hot Racing diff cases, and 2 new center diffs from Jennys. Just put everything into the Hot Racing aluminum diffs, with shims, new sealed bearings and 1M diff fluid !!! I might of well used play dough. They are STIFF! One's going into my Nortorious, and one in my Kraton. For sure won't have front tires ballooning, but will probably bust the pins, or the front or rear diffs. We'll see.