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  1. #1
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    Bashing/Crawling diff oil viscosity/weight

    Hi All,

    I got a used E-Revo 2.0 off of some guy on faceboook and have been having a lot of fun with it.

    I primarily bash with this thing, but I live in the mountains and and have discovered that this truck is a pretty capable (by my standards) crawler as well. I am brand new to this hobby. I have never really considered actual racing, but not against the idea. I primarily bash around the property and enjoy going for walks with kids.

    It had been used and abused pretty heavily by the time I got it, but I got a killer deal. $250! He had done a few upgrades, one of which was a set of GPM CVD shafts (GPM ER2123F/RSA) in the rear. A pin broke on one, and while I can turn out a new one on a lathe pretty easily, the ball ends are pretty worn out, so I am going to remove them. To install (according to product descriptions), I would "disassemble both joints of the sides of the gear box, directly install the joint part and tighten by the shaft screw and pin" ... whatever that means.

    I am guessing I will be splitting the rear bulkheads apart, so I might as well consider changing front and rear diff fluids for some better crawling. I don't like when I see one wheel not spinning when crawling up a rocky hill. In this situation, a bit more gas finally gets it going, but I would like it to act more "locked" at lower speeds. I would like to find a sweet spot where low speed crawling is better, but I still get some diff action on the turns. I am not interested in actually locking them, as the power and weight of this thing would probably shred the drivetrain before too long.

    Less long winded version:
    I am looking for recommendations. I am assuming they currently have the stock 50k now. I am open to putting the same 20M weight fluid the center diff (supposedly) has, but I am thinking this will kill differential action on turns, so perhaps 1M? 500k? I see that the Summit comes stock with 100k front and rear, but that's the older E-Revo 1.0 drivetrain isn't it?

  2. #2
    RC Champion Acidic01's Avatar
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    Put 500k in it. 20m is to stiff and will almost be locked. I have 500k in my xmaxx and love it. Even get tighter cornering as well.....

    I've yet to take my erevo apart and put 500k into front and rear diffs.

    If you find you want it even stiffer then go 1mil or 2mil.

    If you don't run in water at all and want more crawling type action. Look into getting a sensored motor for it. Better low speed response. Most sensored motors are not water proof /resistant



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  3. #3
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    I put the 20m weight in my rear differential and just lunched some diff output gears. Although it doesn’t appear to be breakage, but wear. 500k seems plenty thick in some other cars I have. YMMV

  4. #4
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    Looking at some other forums, 500k to maybe 1m seems to be more or less the consensus, at least as a starting point. Sensored motors seem like a good idea, but this seems to work pretty well for low speed stuff as it is. if this ever burns out I will look into it. I did not know that most are not waterproof though. That is definitely good to know. I don't really intend on running in wet conditions, but the local park has some hidden puddles, especially when I am running flat out a hundred yards away.

    Thanks for the info all.

  5. #5
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    So ... how much do I need per diff anyway? Are the 2oz bottles traxxas sells enough for at least 1 diff? Are there any generic options available?

  6. #6
    RC Champion Acidic01's Avatar
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    Any brand will work for the oil. You can probably fill 10 to 15+ diffs or more with a 2oz bottle. As it doesn't take very much.

    I fill it up till the spider gear are covered. I put some in then drop in my gears. Put some on top. Turn gears some then let it settle for a while then top off.

    The little metal rectangle I forget the name of them inside the diff. Are to go on the shaft in one direction. One side is slightly different. I forget what orientation it is...

    I think the parts explosion shows which way.

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  7. #7
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    Quote Originally Posted by Acidic01 View Post
    You can probably fill 10 to 15+ diffs or more with a 2oz bottle. As it doesn't take very much.
    ...
    Dang! I had no idea it used so little. I will probably just get a couple/few different viscosities then!

  8. #8
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    Quote Originally Posted by Acidic01 View Post
    Put 500k in it. 20m is to stiff and will almost be locked. I have 500k in my xmaxx and love it.
    ...
    Called it! I have been waiting on some parts. I just got it going with the 500k in the garage tonight and can totally see a difference. It will climb walls, literally, and I can clearly see that there is still diff action on at least with slow turns on a concrete floor. We'll see how it does on the hills tomorrow (if it doesn't rain) but I can already see that crawling will be much improved.

    So I am trying to wrap my head around it ... Is having 500k in my E-Revo like having a thicker or a thinner fluid in your X-Maxx? I guess it has more of a "locking" effect because the diff and the wheels are smaller?

    This was my first serious venture into this hobby and I am loving it. I was seriously considering am X-Maxx or one of the Kratons before finally settling on the E-Revo. I found a deal on a used one I couldn't pass up.

  9. #9
    RC Champion Acidic01's Avatar
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    Xmaxx is awesome. Keep a eye out on your local used listings for steals. How I got my xmaxx.

    So the diffs on a xmaxx and erevo are similar. Just slightly different sizes. Or course xmaxx a bit larger.

    I wanna say evero and xmaxx diff oil is 30k stock. Erevo perhaps 50k... So going to 500k in either stiffens it up. I wanna say xmaxx will be a tad stiffer with 500k wt in it.

    The concept is the same in relation to oil wt between the cars as going to thick oil or softer oil from stock will have the same correlation. From diffs to shock oils.

    I have 200k in my 1/16 merv ( mini erevo) diffs which since smaller gives me similar performance to 500k in xmaxx. Since so tiny didn't want to go to stiff.

    Glad you got it together and ready to play.

    Remember car is water proof... So go have fun in the rain. Just wear appropriate rain gear so you dont melt and rust up.

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  10. #10
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    Yeah I tried for a bit today but it was windy and cold. I wimped out. It seemed better I guess? I'll know better tomorrow. As easy as these diffs are to get to, I might just try going even thicker.

  11. #11
    RC Qualifier ElectricPropils's Avatar
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    Quote Originally Posted by aPpYe View Post
    Yeah I tried for a bit today but it was windy and cold. I wimped out. It seemed better I guess? I'll know better tomorrow. As easy as these diffs are to get to, I might just try going even thicker.
    Also, remember that temperature will also affect the performance of your diff fluid. They make them in a way to minimize this affect but that doesn't negate its presence. While slight, I can still notice a difference in diff performance between this time of year (40F) and the summer (100F).
    The present is theirs; the future, is mine.

  12. #12
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    Yep. I will run it for a few weeks with the 500k and see how I like it. The truck really kicked *** today. I could still find situations where I had to gas it a little to get a wheel to grab on, but it was drastically improved from before. Low speed crawling was a blast, and high speed stuff seemed largely unaffected, but I have learned the hard way (over and over again) that I can't bash too hard in these mountains ... Too many rocks!

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