Treal Hobby Arrma Kraton 6S EXB Aluminum Differential Case Carrier (Black)

I want to give this 3.5 stars. 3 seems like too few, but 4 is too much. The quality seems great, the machining is very nice...BUT...the cup itself is just slightly wider than the stock plastic EXB cup which means once installed, there is no room for shims. I installed this on a brand new Kraton EXB bulkhead/diff assembly (Arrma aluminum bulkhead). Brand new, Arrma had installed a single shim on the ring gear side to tighten up the mesh to the perfect spot. Rebuilding that exact same diff with this carrier, the shim will no longer fit which means my ring gear is the shim width (.2mm I believe it is) further out from the differential input pinion gear, resulting in a looser mesh than stock. Hopefully, the stronger EXB diff gear set can take the looser mesh in stride, but I'm not too keen on finding out the hard way (i.e. blowing the teeth out of a set of expensive diff gears). I may try to fix it, but trying to shave down .2mm from this carrier without screwing it up is sketchy at best.

UPDATE 9/19/2024 I can't recommend this carrier. I want to, but I can't. Due to the reasons listed above about the carrier being too wide. Since I'm a professional machinist and have access to the right equipment, I was able to reduce the width of the carrier on the bearing side by .01". Now I can shim it properly and get much better mesh. But the idea that I needed to mount this part in the lathe to fix it at all is ridiculous.

Another thing that I found about this carrier that I don't like is that the four threaded holes for the ring gear screws are not blind. There are reliefs cut at the bottom of the threads which means that diff fluid can leak into the holes. The issue here is that since the carrier is aluminum, the screws should be installed with threadlocker. Since the holes are open to the inside of the carrier, it's quite troublesome to get the holes clean enough to effectively use threadlocker on the screws. I resolved this issue by first installing and threadlocking four short grub screws at the bottom of the holes to keep the diff fluid out. Then I used four shorter 8mm countersunk screws to mount the ring gear.

After these steps were taken, I think the carrier will work well and last a very long time. But if I could go back, I would probably choose a different brand with a better design.