Diff Shimming 101

In this video AJ walks you through the shimming process using an Arrma 6s diff housing. Each manufacturer is a bit different in how they use the diff technology. Still, shimming is shimming and the principles are the same across all of the different platforms. Come along and join the conversation in the comments as AJ does all he can to answer the shim questions we've gotten over the years.
Pinion shim part number for Arrma 6s:
8mm shim, Calandra Racing Concepts - (CLN) #4738
Music:
Epidemic Sound:
Rockin' for decades, You'll learn
Mindme, Quiet Demons

[@rt66rc86]

AJ is the "real deal". I met one of his friends, out of the blue, while running RCs at a volunteer fire station and we got along right out of the gate like we knew each other all our lives! "Mike" said that AJ is a "Top Hand" and one to ride the river with... Of course, those of us who have been following this channel know that AJ is "all in" when it comes to helping RC hobbyists get it right and do it well! We sure could use more like AJ in this hobby! I've learned a great deal watching this channel and have gained a lot of confidence to maintain my rigs because of his teaching and guidance! It doesn't get any better than this!

[@johngallo7383]

I gotta say that your info is on point! Thanks for all you do. It helps older guys like me get back in the game with RC. It's been 25 years since I messed with this stuff. I'm back into it and you info helps out a great deal. Thanks! 👍👍

[@AJJAMStudios]

I appreciate that!

[@ericlongstaff6460]

Forgot to mention, I like your car reviews, unbiased and honest. No matter what car you review, always genuine and informative. I see you are not loyal to any brand (Arrma, Traxxas, Losi, Team Associated, Tekno etc.) just loyal to good RC cars. Peace

[@AJJAMStudios]

Thank you so much. We do try our best to be non-biased.

[@Frumsl84]

Hey I'm from Germany and new to the RC Hobby. Your videos are great and helped me a lot . Thank you

[@love95717]

same, very helpful info

[@underarockandstuff]

Great video! Dif maintenance is important and you simplified it well.🤙

[@AJJAMStudios]

Thanks! 👍

[@SpeedSyko]

🏆🏆🏆🏆🏆🏆🏆🏆🏆🏆🏆 Your Awesome AJ!💪👊🤘Very informative and a great vid! Hope all is well my friend! 🤘👊👍

[@AJJAMStudios]

Sorry for the late reply. We are doing well. Unfortunately it is winter up here and bashing has slowed up quite a bit. I hope you’re well. Thanks again for being here in the comments: it means a lot to us here. 😎👍

[@mithun0984]

Thank you for the info!

[@ericlongstaff6460]

Mr. AJ Jam - One of my favorite bashers to watch and learn from. Extremely knowledgeable and informative. I always tell my friends and beginners about you. Thanks for making my RC car hobby more enjoyable then ever. Peace

[@AJJAMStudios]

It is my pleasure. Thanks for joining us😎👍

[@meirdeaph]

Awsome possum

[@DrJT-ly3vr]

Will watch this a few times... Thx!!

[@camaroboy383]

Ahhhh, finally the proper explanation on diff shimming.. you had me at "ring" and "pinion".. when you said those two words I immediately knew you have been around the automotive world and diffs in general... 👍 As a side note, heel to toe adjustment can be accomplished by shimming behind the inner pinion bearing as well.. 👍... I personally prefer setting my heel to toe first, then working the carrier stack.. it will ensure 100% heel to toe tooth contact... This will be a very helpful video for many.. thanks for being one of the guys that explains it properly.. ✌️

[@ParcoUpchurch]

Excellent video!!! Thx!

[@thisperson4219]

Thank you for being so detailed on the explanation. Very very helpful.

[@AJJAMStudios]

You're very welcome!

[@tom04gsxr]

Great video! Thank you

[@AJJAMStudios]

You are welcome!

[@DrJT-ly3vr]

Best educational channel

[@AJJAMStudios]

Wow, thank you 😎👍

[@matusknives]

Love these technical videos of yours. I am in the process of re-building an Arrma Mojave 6s (got it second hand, some parts failed, so decided to make a full overhaul) and your videos have been very helpful. This one comes with pretty much perfect timing - all 3 diffs were cleaned, oil changed and now is time to put them back in - and the front and rear both had 1 shim (I supposed that is how they come), now I know how to check whether everything is OK. Thank you.

[@AJJAMStudios]

Very cool!

[@l.a.rodriguez9745]

Size of the imput gear washer: 13x19mm

[@ClevelandRips]

You give the best explanations! Thanks!!

[@FantomaS_-86]

Great explanation. Thanks!!!

[@gainsrc]

You did a great job explaining this thank you!

[@AJJAMStudios]

Glad it was helpful!

[@thestoryiheard]

I have had a lot of problems with my diffs on Arrma Outcast 6S in recent years. The rear diff spur was stripped, and the spur was destroyed. I bought an EXB diff on eBay and it served me a couple of rides. For some reason, it always ends with stripping spur gear. The center diff is rock solid, but not a rear one. I installed an open diff with the hope it will last longer. My rig runs on 4S with a speed pinion and without any crazy bash but rather a speed run and a bit of offroad.

[@AJJAMStudios]

Traction is a killer for gearing. Running speed runs, especially on pavement which is done most of the time for speed, puts a lot of pressure on the gearing in the rear, since that is where the majority of the launch weight is shifted to. Tightening up the center diff puts even more pressure on the rear diff - not allowing it to bleed off the extra power to the front end. Still, shimming the "pinion" in the rear diff to close up the gap for the gears is one way to minimize the wear issue; for your diff it requires an 8mm shim: (CLN) #4738 from Calandra Racing Concepts. Also, side shimming for the differential to remove slop is paramount to proper durability. Since the teeth for the diffs are fairly small for the power they handle, the next step might be moving to the EXB rear diff with the LSD plates inside. The gearing is a bit bigger and may handle the power better. Still, we punish our rigs in high traction environments, and we have also suffered diff failures, but with proper spacing in the diffs our losses have been relatively small. Keep in mind, power creates wear and heat accelerates it too. Proper lubrication can prolong the gears for a time, but consistent observation and maintenance should get you the best results. Do not forget, bearings seat in and the gearing can change over a few batteries, so do not forget to check them now and then.

[@VDVC-RC]

Great explanation! Especially on settling & over shimming! I Plan on getting these soon for my Kraton & Ruggified Typhon, but may go with the RCAWD aluminum ones, but keeping the plastic diff bulkheads.

[@AJJAMStudios]

Glad it was helpful!

[@randall4411]

With my three new diffs to maintain i've been wondering how to do it . Thanks for the answer !

[@AJJAMStudios]

Glad to help

[@gooberpea8134]

What kind of hex bits are you using in your dewalt? I’ve been looking for some long skinny ones like that. Thanks.

[@davidzizelman2061]

Great video! New to rc and just got a Kraton 6s exb. Everyone keeps saying shim diffs and some videos were confusing me. It came with a pack of 4 shims for the outside. Some videos I’ve watched mentioned shimming the planetary gears. Im going to take all 3 diffs out to check the fluid. When I open and expose the planetary gears should there be any play with those? Do you have a part number for the shims you are getting for the pinion gear? Thank you!

[@AJJAMStudios]

Excessive play can damage any of the gears. However, we’ve never had to do that. Interesting thought though😎👍

[@fiatfixie4344]

This is helping to explain why my diff started acting up after I replaced the bearings and swapped my ring gear over to a fresher diff. I checked the side to side play but didn't put much thought into the input gear play etc.. Now I'm thinking the gears I replaced still had a lot of life in them. Are you finding that the input and ring gears generally have to be replaced at the same time?

[@AJJAMStudios]

We swap them both at once. Fresh gears with fresh gears. A used one can wear a new one faster. Thanks for asking😎👍

[@armenz.6601]

Aluminum is one of the softest alloys .

[@Top-Jimmy]

Aluminum is the 3nd refinement after Bauxite, Alumina.... I don't understand your point you are trying to make. The Arrma shims are steel.

[@armenz.6601]

Also Arrma shims are not the correct thickness. Two is too many. One is not enough. Where losi shims are thicker and you need just one is perfect thickness

[@Top-Jimmy]

Never had an issue with them.

[@Fre2dy]

No sound,!!!!!!

[@AJJAMStudios]

It is working on our end.

[@gillian9178]

Worked OK for me.

[@chadwitsa]

He wasn’t speaking during the hands on process.

[@AJJAMStudios]

Hey, guys, that was intentional. We prefer relaxing demonstrations as opposed to chatter filled how-to’s. Did the video demonstrate how it’s done?

[@gillian9178]

@@AJJAMStudios Yes easy to follow.