Kraton Kraton EXB Differential situation?

[jackka]

So Arrma's CEO Jason Dearden told us that the Kraton EXB rear diff issue at the factory has been fixed. And I believe he said that future batches of the Kraton EXB will ship with LSD for both the front and rear, as opposed to the original LSD in the fron and open diff in the rear configuration. Is this true? Because it makes me thoroughly confused.

1. What was the reasoning behind it originally shipping with an LSD in the front and open diff in the rear?
2. What is the reasoning behind now switching both to LSD? Open diff no good?
3. Some members have said that having a LSD in the rear makes the car handle like crap. I'm curious why this would be, and what the best front and rear diff combination would actually be.

 

[dk3000]

You are definitely late to the party. They made the change from open diff rear differential to lsd diff options as a fix or temp fix to a massive issue with the open diff design and QC. The open diff design was I believe the best for driving but a fix was needed. They are not changing the front to my knowledge and since it is 29mm it fits in the rear. Easy fix for them. I hope it's temporary but really only time will tell.

 

[SentFlying]

Edit

 

[jondilly1974]

There is a thread here somewhere where someone received a replacement diff that had 12x18x1.9mm shims instead of LSD plates for a rear open diff. Nothing official about that being the fix, but I would hope it is true.

 

[Brisbane_North]

https://www.facebook.com/groups/889415401161941/permalink/2772952109474918/

Basically, the more you lock the rear the more the car wants to do donuts when turning under power - so an open rear diff is best for handling.
The original open rear diff has a little "give" in it causing the sun gears to strip...the more power the easier it strips.

The second batch will have an LSD rear diff - but LSD x1 - meaning minimum LSD effect.

You can also still have an open rear diff as long as you replace the 3 LSD plates with the 12x18x1.9mm spacer...

 

[jackka]

https://www.facebook.com/groups/889415401161941/permalink/2772952109474918/

View attachment 106716

Basically, the more you lock the rear the more the car wants to do donuts when turning under power - so an open rear diff is best for handling.
The original open rear diff has a little "give" in it causing the sun gears to strip...the more power the easier it strips.

The second batch will have an LSD rear diff - but LSD x1 - meaning minimum LSD effect.

You can also still have an open rear diff as long as you replace the 3 LSD plates with the 12x18x1.9mm spacer...

Ah, now everything makes much more sense. Thanks for all the info!

Curious why Arrma didn't decide to ship the second batch with the 12x18x1.9mm spacer, as it seems to be a better solution than the LSD x1.

 

[jondilly1974]

Ah, now everything makes much more sense. Thanks for all the info!

Curious why Arrma didn't decide to ship the second batch with the 12x18x1.9mm spacer, as it seems to be a better solution than the LSD x1.

Agreed. The LSD rear is terrible to me. I even tried 3x star plates (no circle) and it was still way too locked. Only 12x18 shims opened it up enough to turn under power.

 

[Rcproponent]

Agreed. The LSD rear is terrible to me. I even tried 3x star plates (no circle) and it was still way too locked. Only 12x18 shims opened it up enough to turn under power.

@BashingBrian ’s fix with the 12x18 shims is the only way to go ??Feels like an RTR with the added beef factor that was SUPPOSED to be there from the start. super solid now. ????

 

[jondilly1974]

@BashingBrian ’s fix with the 12x18 shims is the only way to go ??Feels like an RTR with the added beef factor that was SUPPOSED to be there from the start. super solid now. ????

Oops I forgot to shout out @BashingBrian ??‍?

 

[suchtragedy]

@BashingBrian ’s fix with the 12x18 shims is the only way to go ??Feels like an RTR with the added beef factor that was SUPPOSED to be there from the start. super solid now. ????

I have done the 12x18 shim solution as well with a slight variation and am very happy with it. I went with one extra 6.2x13.7 0.2mm Arrma shim added to the 3 stock shims stacked under the output shaft pins and then I added a stack totalling 1.7mm of the 12x18 spring steel shims (0.5mm x 3 + 0.2mm x 1) behind the sun gears. It felt a tiny bit notchy after dry fit reassembly but I decided to run it so I filled with 10k diff oil and after a pack it felt smooth and no broken teeth noise and continues to work great no issues after 6+ packs through it.

I run this rear setup combined with the middle and front diffs still equipped with stock LSD plates with 25k front, 100k center diff oil and I been really happy with how it drives and turns now. The only things that I've broken on my EXB since doing this has been my plastic rear wing mount ?

 

[jondilly1974]

I have done the 12x18 shim solution as well with a slight variation and am very happy with it. I went with one extra 6.2x13.7 0.2mm Arrma shim added to the 3 stock shims stacked under the output shaft pins and then I added a stack totalling 1.7mm of the 12x18 spring steel shims (0.5mm x 3 + 0.2mm x 1) behind the sun gears. It felt a tiny bit notchy after dry fit reassembly but I decided to run it so I filled with 10k diff oil and after a pack it felt smooth and no broken teeth noise and continues to work great no issues after 6+ packs through it.

I run this rear setup combined with the middle and front diffs still equipped with stock LSD plates with 25k front, 100k center diff oil and I been really happy with how it drives and turns now. The only things that I've broken on my EXB since doing this has been my plastic rear wing mount ?

Yep wing mount for me too.

 

[dk3000]

Broke my left rear shock rod end on a cartwheel last week on my exb.

 

[Jimbobjr]

You guys are like the Arrma r and d but unpaid...

I haven’t had the pleasure of messing with the new diffs. Looks like the Mojave exb has the new diffs front and rear. Can you tell from this picture if they are the same configuration as the Kraton exb or is there something added to fix the issue you folks are having?

 

[Surchaufeur]

The new open diffs will come with a 1.9mm spacer. And i hope the part number comes out soon to put that in my rear diff im still running a somewhat LSD setup in the rear and with crazy onder steer on grass

You guys are like the Arrma r and d but unpaid...

I haven’t had the pleasure of messing with the new diffs. Looks like the Mojave exb has the new diffs front and rear. Can you tell from this picture if they are the same configuration as the Kraton exb or is there something added to fix the issue you folks are having?

View attachment 106877

The rear exb diff of the kraton would have the thick 1.9m spacer of what im aware of. And the exb mojave wont have an open diff

 

[jondilly1974]

You guys are like the Arrma r and d but unpaid...

I haven’t had the pleasure of messing with the new diffs. Looks like the Mojave exb has the new diffs front and rear. Can you tell from this picture if they are the same configuration as the Kraton exb or is there something added to fix the issue you folks are having?

View attachment 106877

While they don’t show the sun gear shims in that pic, everything else seems the same as my EXB front.

 

[JayP.]

Has anyone actually used the revised open EXB differential? If so, how's the durability been?

 

[Dak08]

I've ran 6 packs in mine with no issues. I replace fluid R20k C200k F30k and added shims behind the out drive pin.

 

[JayP.]

I've ran 6 packs in mine with no issues. I replace fluid R20k C200k F30k and added shims behind the out drive pin.

I totally missed the notification for this reply, my apologies. Was that with the revised open diff? Seems silly you'd still need to go in and add MORE shims in the apparently "revised" differential. I could understand the external gears (ring and pinion/input, whatever people call it).

 

[jackka]

I totally missed the notification for this reply, my apologies. Was that with the revised open diff? Seems silly you'd still need to go in and add MORE shims in the apparently "revised" differential. I could understand the external gears (ring and pinion/input, whatever people call it).

I think he means adding shims on the outside of the diff to make the fit and gear mesh tighter. They are not the shims that go inside the diff that replaces the LSD plates.

 

[JayP.]

I think he means adding shims on the outside of the diff to make the fit and gear mesh tighter. They are not the shims that go inside the diff that replaces the LSD plates.

Okay, I was a little confused about that. Makes more sense.