What diff fluids do you run and why?

[hawg78]

OK guys my Rock Rey is my first RC and already wasted the front diff case. Seems as though there was a missing C-clip on one of the front lower arm hinge pins. When the front wheel took a hit from a tumble the pin dislodged from the front pivot and broke and peeled the side of the diff case like an orange peel.

Anyway I am replacing the diff with an SSD case and HR diff cup. Also installing an SSD 3rd member in the rear, diff cup and replacing all bearings. During disassembly I found some loose screws and leaking diff fluid so I am going to go through all three diffs (transmission too) to upgrade and assemble the correct way.

My question is what are you guys running for diff fluid weights in the three diffs. I mainly just do grassy terrain, wooded paths and gravel and minor jumps. No rock crawling to speak of. Just balls out kinda stuff.

Thanks much.

[Panther6834]

Initially, I replaced front/center/rear with 10K/15K/80K (the majority of my vehicles prior to getting my Baja Rey have been off-road race). After running a few times, and realizing I needed to go MUCH heavier, I replaced with 100K/500K/2.5M.


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[hawg78]

Hey Panther,

Wow those are heavy weights. So you are really limiting the rear more than the front. Makes sense for steering.

Thanks for the feedback.

[Panther6834]

Originally Posted by hawg78

Hey Panther,



Wow those are heavy weights. So you are really limiting the rear more than the front. Makes sense for steering.



Thanks for the feedback.

Yes...and, rear really needs to be 'limited' more than front (or center). I didn't want to lock the rear (Losi does have an available locker, that replaces the diffs gears), but I also didn't want a "limited-slip"...I wanted to create sort of an "ultra extra-limited-slip".

I felt the 1M wouldn't be 'limited' enough, and the 20M would have probably been no different than using the locker. The other part of the 'problem' is that the diff isn't a sealed diff - it's "open". Use too thin of a diff fluid, and it can/will leak out, into the axle housing. I had initially solved this by "plugging" the ends of the diff with a thick marine grease before filming the cup with diff fluid, which worked extremely well...but, again, the rear wasn't "limited" (as it is now).


~ More peace, love, and kindness would make the world a much better place

[hawg78]

Hey Panther,

So when you say you plugged the diff ends with the marine grease you mean you packed the two silicone o-rings behind the two gears and gear shafts with the grease?

Thanks much for your input. I have 500k and 2.5M fluids. Can't seem to find anything around 100k yet.

Take care ok.

[OutLore]

Where are you all getting your diff fluid? Seems that everything is always out of stock especially at the 100k+ levels

[Panther6834]

Originally Posted by hawg78

Hey Panther,



So when you say you plugged the diff ends with the marine grease you mean you packed the two silicone o-rings behind the two gears and gear shafts with the grease?



Thanks much for your input. I have 500k and 2.5M fluids. Can't seem to find anything around 100k yet.



Take care ok.

Starting with the diff cup, I packed the bottom of the cup (where the driveshaft goes through), with the marine grease (Maxima Waterproof Grease, of you're interested in knowing...what I also use for all gears, and for lubing the flex shafts in my boats). Next, I greased the O-ring (same grease), and carefully placed the first main diff gear into its spot. Then I filled the diff cup 1/3 full with diff fluid, and let it sit for about an hour (2.5M fluid is incredibly viscous, so I wanted to give it plenty time to 'spread'. After that, the spider gears went in, followed by more diff fluid, and waited another 30min, or so. When I checked it again, I knew it needed a little more diff fluid, so added, and waited.

Once I was certain it had enough, I filled the top driveshaft hole with grease, then carefully placed the other main diff gear on top of the spider gears, then the gasket, and finally I placed my paperclip pieces into the screw holes (to aid in properly aligning the diff cap/ring gear). For the paperclip pieces, two are slightly longer then the other two, with the shorter pieces across from each other, and the longer pieces across from each other. To insert the first two screws, I removed the two shorter paperclip pieces, and screwed in the two screws into they were almost-but-not-quite-tight. Then I removed the other two paperclip pieces, and added those screws. Tighten screws on a 'X' pattern.

When putting the rear axle together, I started by placing the diff bearings in place, then placing the diff into the axle, and then I held the axle in a vertical position with the bottom of the diff cup facing downward. Next up (literally) was inserting one driveshaft from the bottom (with bearings), and screwing the end-cap into place. Finally, I repeated the driveshaft process on the other end, inserting it downward into the diff cap/ring gear. Final step - attaching the third member...and axle built.

Hope that helps.

Originally Posted by OutLore

Where are you all getting your diff fluid? Seems that everything is always out of stock especially at the 100k+ levels

I was able to get the 80K from my LHS (they had three), but I got the 100K, 125K, to 500K, and 2.5M from Amazon (as much as I REALLY dislike Amazon), and eBay.

~ More peace, love, and kindness would make the world a much better place

[hawg78]

Hey thanks Panther I will try your process when I reassemble.