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Discussion Starter · #1 ·
On of the soundest upgrades you can make to your new Savage is the 4 gear diff mod.


This involves changing the current gear axle to a pair of crossover axles and adding an additional 2 spider gears into each diff.





I highly recommend that while your are in their, lock them up a little with a high quality Silicon Diff Oil. I used 5000wt Front and 3000wt Rear.


For a full rundown on the process, visit Savage Central.


Savage Central - Diff Mod


Regards,


AUSRCEdited by: AUSRC
 
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i am currently in the process of purchasing a savage should i do the upgrade straight away or wait for a while
 

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hay good to see you made it, so far i havent upgraded and the diffs are doing fine, i think its only necessary when you either blow the diffs, or upgrade to an aftermarket engine
 

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Discussion Starter · #5 ·
DomSavage,


SG is probably right, but I did mine before it had even been started for break-in. I thought it was a good investment in time (you get to know the truck by stripping it down) and it is not a lot of money.


While I had the truck stripped down I also installed the HD dogbones. This adds a bit to the cost, and is probably not as necessary as the diff mod, IMHO.


Regards,


AUSRCEdited by: AUSRC
 

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Hi Guys,

I did this mod as soon as my 25 arrived and have never had any drama's with my diffs at all. Now that I have the Picco26 in, it makes it even more worth while to have had this done.

I have just stripped my whole truck down for routine maintenace and am now going to try 5000wt in the front and 3000wt in the rear. Previously I had 3k front and 1k rear.

Another important thing to note....if you do this upgrade, remember that the silicon fluid will eventualy leak out, so about every 4 to 5 litres through your truck, strip it down and re do the diffs.
 

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Discussion Starter · #7 ·
Hirisk,


I am running 5000 and 3000 and find it a really solid combo. I also run 40 Series Velocity 6 wheels with Big Joes, and even with the larger rubber, those diffs lock up beautifully.


Not the best if you intend on much tarmac work though, the setup is definately suited to the looser surfaces.


Regards,


AUSRC
 

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Chers for the feedback,

I am planning on running at the Dandenong track a bit this year and their surface is a bit loose, so I am looking forward to it.

Cheers,
Shaun.
 

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Yes, I think it would be. You actually would only start going to the higher weight oils for things like Rock and Hill Climbimg.

For racing you actually do want the differetial to still work somewhat, rather than just lock itself withh the heavier oil.

Still, 7k/5k will be OK, but just don't go any heavier.
 

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If you have already reasembled everything, don't bother pulling it down just to change from 7k to 5k, but if you still have everything out of the truck, yes, I would go 5k front and rear and see how that goes at Dandy.
 

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i would reccommend doing the mod straight up i was to keen to get going with the picco in and destroyed the diffs within the 4l stage and pushed the pins off centre taking out the cups i run 7000/3000 and love it well worth it would also say do yourself a favour and use the longest screwws you can to hold the crown onto the cup or you will be up for new crown and pinion learnt the hard way goodluck
 

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After stripping two diff cups b4 doing the mod I would have to agree
with Leroy aswell as those who suggest to do the mod b4 u even
run the truck. This is what your diff cup will look like if you dont





I got rid of the hpi supplied 12 mm long coarse thread screws and
replaced them with 22 mm fine thread screws. With these screws even if
the pins do start to move in the diff cup they will only move to where they hit the screw and CANT move anymore :)
If anyone has stuffed their diffs and are waiting for parts to get back
on the road you could always make a home made locker with some epoxy
putty, like so




Edited by: Odum
 
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