Outcast Looking for recommendation for a stronger front rear and center diffs

Dan B.

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I’ve heard many say proper shimming and don’t land on the throttle. Someone recommended to me that I use the Hot Racing bulkhead covers (just covers, not whole bulkheads) to eliminate all flex. Metal diff cases? I’ve heard both ways on that one.
I’m not aware of any other alternatives to Arrma diffs.
@SrC has a broad knowledge of all the 6s diffs, any recommendations?
 

SrC

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Regarding 6s "Open" RTR diffs, I have best longevity along with good driveability running 60k F/500k Center/30k R. ( all my Offroaders)
Shimming the Main gear is critical. Always have spare shims. I use Tekno TKR1222's.
I only use plastic stocker bulkheads FWIW. But on 1 rig am using the HR Bulkhead alloy Top Cover only and HR alloy Sway bar bracket. (keeps the sway bar from flexing at the center) The rear is the priority IMHO. I use the Arrma Metal diff case only at the center on most of my rigs. Center diff seems to last longer. Center runs hottest IMO. I melted a center plastic diff already. Temp over 212F degrees. It became a molten lump of plastic and gears. Bricked. You could try using the metal diff case it at the Rear and/or Front. I personally like my diffs lighter (plastic) on F and R diffs.
Proper filling is critcial. An underfilled diff will overheat easily and diff action will feel like you are using a much thinner oil.
There is a learning curve to building Arrma 6s diffs. Or any similar style RC diff. After about 60+ rebuilds, you will get the hang of it.:giggle:
Like @Dan B. , stated above, driver error will get the best of the diffs. Use no throttle/load on landings and impacts. Much damage occurs otherwise. A common Newb mistake. Get rid of bad habits.
I find the rears get the most abuse. Require more attention.
I use a smear of grease on the output cups before installing them and I use a shock lube or silicone grease on the Diff's O-rings. Like Tekno manuals do it.
I let the air bleed out in the diff oil before closing it up, checking and adding as needed. Air that escapes makes more room for oil. (proper fill) Letting the diff sit for 20 min +. You cannot fill a diff properly if done fast. I use a Shock vacuum pump to do this. Faster and more precise. But not necessary if you are patient and let the diff sit open to bleed out air bubbles. You can't see them. I fill oil a little at a time. Before and after installing the sun gears. Little at a time. Bleeding air out is quicker this way.
Bulkhead gaskets are available, (TekJo and BQ has them). I just smear grease on the bulkhead bottoms where it meets the chassis to keep out fine sand and dirt. Use any Automotive grease on the main and Input gears. Liberal is ok. Just don't pack the whole bulkhead with grease. Makes a mess and doesn't add more lubricity. Less is more here. My diffs generally last about 20+ runs before they start to get tired. I'll keep an eye on them. And maybe rebuild a leaking or damaged one as needed. Depends on the rig and how hard you bash. I am not a big air guy myself. But do small jumping here and there. If just doing 40 footer big sends etc. all day long, Expect to replace diffs more often. Is what it is. 1/8 Arrma diffs just tend to be needy.
I could go on and on. But you get the picture.... Just jump in and start rebuilding your diffs. It will become second nature.
:cool:

EDIT:
With the exception of Oil CST, most of the above also applies to EXB LSD diffs.
 
Last edited:

Matt05

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I run 1 million/ear plugs/500k in my 8s Arrmas, which I believe is what you are working with. On my Kraton I have the aluminum diff cups front and back. My Outcast I will probably switch to the vitavon v2 ones over the winter.
 

Jeppyjep

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I run 1 million/ear plugs/500k in my 8s Arrmas, which I believe is what you are working with. On my Kraton I have the aluminum diff cups front and back. My Outcast I will probably switch to the vitavon v2 ones over the winter.

How’s it been so far ? I just ordered a 7075 diff locker that replaces all internal gears from bulletproof RC better grade then the 6061s on eBay so will see how that does . I have 500k in the rear and front and had 20 mill in the middle . I think I landed on throttle on this big beech . I never have problems rebuilding my 6s diffs they always last along time . Just this 1/5th center has been busting my balls so I’m going try the locker

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SrC

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  4. Kraton 6s
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  6. Notorious
  7. Outcast 6s
  8. Typhon TLR
With a locker, you wont need anymore 20 mil there.. I don't know what 30 pounds of moving mass will do to the rest of drivetrain however.
Let us know how it goes.(y)
 
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