Diff oil questions

[Nadboo]

Hey all,
I'm very much still a noob so please bear with me. I have a few diff questions,
Can someone explain diff oil thickness to me? Is thicker or thinner types recommended for the flux? What are the effects of thicker vs thinner oil? Would a certain thickness be easier on the lifespan of the diff, i.e. Thicker slows it down so I'm guessing maybe more torque on the parts. I really don't know, just guessing.
Last night I took my Savage 25 converted to brushless for its second run and after about20 min of bombing around a baseball field I dramatically lost power and it seemed my 4x4 became a front wheel drive. The rear wheels still turn but not even close to how fast the front move. I did a little test lifting just the front wheels and pushing the car. Going backwards it turned the motor slightly, going forward there was no movement on the motor, on the front wheels the motor spun forwards and backwards normally. Without opening it I'm guessing the rear diff is toast. Probably the case, Both front and rear diff only had the 2 spider gears in a plastic case. I just ordered some complete aluminum diff from a savage x flux hp which I assume have 4 spider tougher gears than mine.

I kinda knew (hoped) that would happen, I love being forced to upgrade lol.
Thanks

 

[LeroyX]

Diff oil acts as kind of a limited slip system, thin oil or just a little grease will get you power to basically one wheel at a time. Thicker oil will help lock up the diff and provide more equal power to both wheels. Personally I like using thick oil like 300k or I think I even have some 500k in the rear and about 80k to 100k on the front. This seems to give me better traction and also doesn't seem to affect steering too badly.

You'll have to tear down the truck to see what has broke. Assuming you checked that you haven't stripped a wheel or lost a pin on one of the driveshaft cups its probably diff related or a stripped pinion gear.

Good luck!

 

[zuchtfam]

Little off topic but where did you order the upgrades from? I also have a flux and am curious where other guys are ordering from.
Thanks

 

[Nadboo]

I usually google the part numbers or the upgraded parts and see what comes up. Most of them are from eBay and are new parts stripped from unsold models. Be careful though, there is one company, who " appears " to have everything in stock and prices are all cheaper than everywhere else. Typical "too good to be true" situation. Besides eBay, I've found parts at my local store, online stores like tower hobbies, and dollar hobbies. It has crossed my mind to get another savage just for parts. Good luck!!!

 

[Wheelspinn]

Would that company be Active Powersports? I spent a lot of time putting together a big parts order, waiting a week for them to ship, called them and they said, "oh sorry we're out of stock on those items". Definitely a disappointment.

 

[Nadboo]

Would that company be Active Powersports? I spent a lot of time putting together a big parts order, waiting a week for them to ship, called them and they said, "oh sorry we're out of stock on those items". Definitely a disappointment.

Yes, that’s the company. I wish I could omit them from my searches

 

[olds97_lss]

Yes, that’s the company. I wish I could omit them from my searches

I can't even find that user on ebay.

 

[Jam Racing 1]

If you ask me diff oils are mostly for racing platforms, which we all know none of the Savages are, for most bashing duties you can get away with using heavy grease packed into the diff cup depending on how heavy the grease is you will see differing results and on a bonus note the grease stays in the diff and hardly leaks out at all unlike oils....

 

[polarman]

I typically use 300k in the rear for traction and 100k in the front for easier steering. I tried packing the rear diff with silly putty once to try to make it like posi traction. Didn't work, so don't bother trying!

 

[olds97_lss]

As a basher, I run relatively thick oil in the diffs so that even when I get high centered, power is still supplied to the wheels touching the ground. Also, thicker oil leaks out less.

With grease, the diffs tends to be more open/free spinning when one wheel is on the ground sending the majority of the power to the wheel in the air.

I'm currently running mugen 50K in both my flux and my X. It's about the consistency of cold honey. Have to squeeze/smash the bottle to get it out, then give it a decent amount of time to settle in the diff until it's up to the top of the cross bars.

 

[LeroyX]

If you ask me diff oils are mostly for racing platforms, which we all know none of the Savages are, for most bashing duties you can get away with using heavy grease packed into the diff cup depending on how heavy the grease is you will see differing results and on a bonus note the grease stays in the diff and hardly leaks out at all unlike oils....

Probably true but tinkering with stuff because you can is half the fun! To go against my earlier post I have now changed out my super heavy rear diff oil with 75k. I liked the heavy oil when the truck was nitro powered but now that its electric it was way to hard to keep straight on the loose dirt I run in most often. Lighter oil in the rear made a massive difference in handling and also helps keep the front end down a bit too.