Kraton Kraton 4S - Diff and shock oils

[Gedrick]

Hey guys, couldn't find a thread on the subject so here we are.

My K4's got a good bit of packs run through it so far, and it's about high time for some routine maintenance. I'm planning on a diff rebuild (cleaning+fluid swap) but am unsure what numbers to run. What's everyone running front/rear?

Same goes for my shocks. I have 50wt shock oil on my Rustler on all four shocks, but I feel it may be too light given the significant difference in both truck and shock cylinder size. What kind of weight are folks running on shocks for general use? Mix of jumping 6-10 feet high on to grass as well as ripping around a dirt track and off-road terrain. Pretty light duty for this fella.

I'd like to go ahead and order enough for a couple rebuilds so trying to get this right the first time. Curious as to any and all input! Thanks in advance.

 

[SrC]

If it runs fine stay with stock. The v2 4s rigs are fairly new still. Took Arrma a real long time to get the V2 4s into production. It is much different than the V1's. I want to say they got the oils correct. They just may be underfilled as usual. Nothing new here.
You are treading new waters. Pave the way for others. Experiment based on what you feel are the drawbacks if any at this point.
If it were me, I would stay with stock weights and keep driving it. Need much wheel time to get a better idea of what to change if anything. Adapt your driving to the rig. Not the other way around. The rig should not control you. You control it and its setup. Driving input should not be reactive, Your inputs drive the rig. The shock and diff oils should be adapted to IMHO.
Definitley do the maintenance however. Remove the Power Module regulary, clean out and inspect mesh and check if the Motor mount is bent or tweaked. This is the first thing to do on your wrenching list! Where I would start.
Even 10-15 packs in, the rig is still new to you. IMHO. For all of us, any new rig.
But it's definitely ready for serious maintenance. Bumper to bumper.

 

[JPWSRC]

Shock oil weight is 500cst I believe.
Diff weight is 10k.
Seems most folks feel the shocks perform flawlessly. I wouldn't fix anything that's not broken.
As Steve said above diff weighs are your call on how you like the car to handle in your typical environment.
I run in light to thick grass mostly and on my V1 4s rigs I run 15 to 20k at the rear and 40 - 50K up front. Some run up to 100k in front but they're bashing style supports that.
I just built my OC4 and used 20k up front and 10k in the rear. The shocks I bought from JRC were all filled properly, so odds are good yours won't be far off, unless you have a leak.
Good luck experimenting and have fun!

 

[BigSmokey]

I noticed all the air in the shocks makes them collapse at the end of the stroke. Topping them off with 500cst would be a great upgrade to help bottoming out on jumps, air mixing in the oil makes it behave thinner. Thats where you should start. Then go up 1 weight at a time, and see if your car is still stable on the terrain YOU run most. Too thick, car gets bumpy and unstable you can see it bouncing around fighting itself. I have 610cst and it's good for jumps, smooth fast terrain, but not as fast running thru rough Footprints in the sand as stock was. I'll try ~550 next time till I find what I like, maybe even back to 500 with no air after that.

 

[SrC]

^^^
+1
Out the Box I found most Arrma 6s shocks to be filled well enough. But I always remove them, then remove the spring and check the shock stroke by hand. If you can hear the air at the extreme stroke, yes they are a tad Underfilled and/or Have too much air in them. They will need some attention. And you should top them off as shock pairs so they are a matched set. Fronts and Rears. Many overlook this, sometimes end up chasing a ghost trying to find out why it handles poorly, jumps etc. But is actually just the shocks.
Many overlook the shocks.

 

[Velodromed]

Hey man, I forgot that you have a 4s rig. Since you’re going to be working on it, if you have a chance could you snap a picture of front and rear driveshaft where they connect to the diff? I got my driveshafts off a parts breaker, noticed that they’re different and I can’t tell which go on the front or rear (The online exploded view doesn’t really show). I’m also having difficulty attaching the sway bars. Doesn’t make sense where they connect to the bulkhead, it’s not like a 6s car.

I also got one of the new differentials and it was ‘more full than normal’ when I opened it. Touch over 2/3rds. Sticking with my tried-and-true appx 15K rear, appx 25K front.

Thanks!

 

[Kraton4s]

I noticed all the air in the shocks makes them collapse at the end of the stroke. Topping them off with 500cst would be a great upgrade to help bottoming out on jumps, air mixing in the oil makes it behave thinner. Thats where you should start. Then go up 1 weight at a time, and see if your car is still stable on the terrain YOU run most. Too thick, car gets bumpy and unstable you can see it bouncing around fighting itself. I have 610cst and it's good for jumps, smooth fast terrain, but not as fast running thru rough Footprints in the sand as stock was. I'll try ~550 next time till I find what I like, maybe even back to 500 with no air after that.

Sorry for a dumb question but what is the difference between cst and csp. I keep seeing different brands listing both. Thank you