Outcast Tired of blowing diffs with the XLX2 and 1100kv!

[Armarookie43]

I love my 8s Arrmas BUT I'm tired of blowing my diffs and center differential. Can you please tell me if it's me and my crazy driving? Or the 12HP XLX2 system causing these bolts to come loose after like 5 runs. Aluminum diff cases installed, I toghten them super hard and use red loctite. And they still come loose. I even degrase the bolts! Anyone else? If you don't have this problem, do you use stock electronics or what electronics do you use?

 

[SrC]

I imagine a much thicker oil will save the Sun gears more so? IDK. Not sure how yours is set up. What you've tried already.
I don't own an 8s rig. But follow many 8s threads here.
Just my experience with 6s rigs. Thicker diff oils usually makes my diffs sun gears last a bit longer overall. Sorry I can't help much more.
And proper Sun gear shimming is a given.

 

[StephenSchandelmayer]

Yeah I have seen this problem with all 3 of our 8s trucks. Thnakfully I have never actually killed the diff, managed to hear it before it did any real damage. But it does seem like a bit of a flaw. I am assuming you let the loctite get nice and dry (24 hours) before running it?

 

[Armarookie43]

Yeah I have seen this problem with all 3 of our 8s trucks. Thnakfully I have never actually killed the diff, managed to hear it before it did any real damage. But it does seem like a bit of a flaw. I am assuming you let the loctite get nice and dry (24 hours) before running it?

Yup. Like 3 days. It's very frustrating. What electronics are you using? My personal opinion is that those very thin bolts used on the diffs and the center of diff are way too thin for these 30lbs beasts doing over 50mph with 15HP.

I imagine a much thicker oil will save the Sun gears more so? IDK. Not sure how yours is set up. What you've tried already.
I don't own an 8s rig. But follow many 8s threads here.
Just my experience with 6s rigs. Thicker diff oils usually makes my diffs sun gears last a bit longer overall. Sorry I can't help much more.
And proper Sun gear shimming is a given.

It's not the internal gears that are my problem. It's the stupid little bolts that hold the ring gear to the diff cases (the ones in the center of diff are also the same size). They get loose no matter what what I do . Once they get loose, they damage the sun gear. I'm not even sure what gets damaged inside the center diff yet. But I know it's making noise. The center diff has 20 million weight from factory.

 

[SrC]

I think some have tried Vitavon alloy diffs with better luck? The screws won't back out......
But I am far from any knowledge or experience with the 8s line.

 

[RCbuzz]

Did you have this problem with the plastic housing as well? I wish I had more run time on mine to provide feedback. I don't bash as hard as you guys either. Running a Max5 with the 1100KV motor, stock spur and 30T pinion.

Had to rebuild the center diff due to a noise, ended up adding an earplug as it was half empty. Used really thick low strength thread locker on one side and regular blue on the other.

Let you know how it holds up but so far the thick lower strength stuff seems to hold better than the thin medium strength blue.

 

[LibertyMKiii]

I'd be curious after running it really hard and then shoot a temp gun on the diff case and see what the temps are.
You have to get red Loctite pretty hot to make it break the bond. Surely the diff is not getting that hot, but just curious about what temps it is reaching.

Thicker fluid would help reduce the temps, bu this changes the front wheels unloading the power and the overall handling. It seems like M2C or some other brand needs to make one with larger screw provisions.

 

[StephenSchandelmayer]

Yup. Like 3 days. It's very frustrating. What electronics are you using? My personal opinion is that those very thin bolts used on the diffs and the center of diff are way too thin for these 30lbs beasts doing over 50mph with 15HP.

It's not the internal gears that are my problem. It's the stupid little bolts that hold the ring gear to the diff cases (the ones in the center of diff are also the same size). They get loose no matter what what I do . Once they get loose, they damage the sun gear. I'm not even sure what gets damaged inside the center diff yet. But I know it's making noise. The center diff has 20 million weight from factory.

My dad and I are using max 5 with hobbywing 56113 800kv 34/39 gearing. My brother is using a xlx2 with a tp 56 x 112 1450kv or something and same gearing and hes got his all water cooled and stuff so its really heavy. His just had the issue of the screws backing out like a week ago but nothing actually got hurt

 

[Armarookie43]

Did you have this problem with the plastic housing as well? I wish I had more run time on mine to provide feedback. I don't bash as hard as you guys either. Running a Max5 with the 1100KV motor, stock spur and 30T pinion.

Had to rebuild the center diff due to a noise, ended up adding an earplug as it was half empty. Used really thick low strength thread locker on one side and regular blue on the other.

Let you know how it holds up but so far the thick lower strength stuff seems to hold better than the thin medium strength blue.

Actually the plastic housings do the same thing and worse because they break apart and completely destroy the gears. I took apart my center diff. I found one of the sun gears is stripped. I have like two more center diffs in pieces, so I'm going to use the sun gear from one of those. The spider gears seems fine. I'll clean them up and double check.

 

[sandblaster]

Heat is the issue. Has anyone tried to aim a good ESC fan at the diff? Aluminum absorbs heat easy. As noted takes a lot of heat if red locate is used proper. Are you useing brake cleaner on the holes and threads? Takes no oil for the lactate to do it's job. In heavy equipment have seen red locktite do such a good job the part had to be cut apart. Heat would not do it. So something is amiss with it's use I think. Be real easy for the heavy oil to get in the holes or on the bolts as they are installed. Thinking the ear plugs might be better as in easier to control where the lube is, to stop possible contamination. Thoughts of a retired HD equipment tech.

 

[Armarookie43]

Heat is the issue. Has anyone tried to aim a good ESC fan at the diff? Aluminum absorbs heat easy. As noted takes a lot of heat if red locate is used proper. Are you useing brake cleaner on the holes and threads? Takes no oil for the lactate to do it's job. In heavy equipment have seen red locktite do such a good job the part had to be cut apart. Heat would not do it. So something is amiss with it's use I think. Be real easy for the heavy oil to get in the holes or on the bolts as they are installed. Thinking the ear plugs might be better as in easier to control where the lube is, to stop possible contamination. Thoughts of a retired HD equipment tech.

Thanks. I even soaked the diff case overnight and the bolts too. And it still came loose. Maybe it's the material used? The Arrma aluminum leaves a lot to be desired. And the bolts too

 

[sandblaster]

The metal could be soaked through with the silicone oil. Understand silicone is very hard to remove from some material. Aluminum is among the porous material, I think. Might be time to try a new case and new screws with the ear plugs. Still use brake clean. The only thing to do a good job of removing oil and leaving nothing behind. Use will plenty of ventilation. Think fan could be big help. Cleaning solvent leaves a residue.

 

[Matt05]

Ever try the v2 vitavon diff cases?

 

[Clubin]

Don’t reuse the gears! Even if they look good - chuck em out!

I put vitavon cases in my Kraton 8s with xlx2 and 2028 1100 castle.

No issues.

https://www.ebay.ca/itm/28490907961...CdB2YqORAu&var=&widget_ver=artemis&media=COPY

 

[Armarookie43]

Ever try the v2 vitavon diff cases?

No. I think that I'm going to go with brake cleaner again. I've also tried that too. But I have to keep trying. I'm also going to reduce the power and punch on the XLX2. That should help. TBH, I don't need 12HP. What I need is long term durability and reliability.

Don’t reuse the gears! Even if they look good - chuck em out!

I put vitavon cases in my Kraton 8s with xlx2 and 2028 1100 castle.

No issues.

https://www.ebay.ca/itm/28490907961...CdB2YqORAu&var=&widget_ver=artemis&media=COPY

Well I have a whole bunch of them just laying around. And I can't buy anything right now since I don't have money. So I have to roll with what I got. Last time I only replaced it the sun gear on one of my Arrma diffs with the same issue and It was OK. How long have you been driving your rig?

 

[Licklobster]

Likely your screws are too short, a lot of aftermarket cases are too shallowly threaded.

The best way to prevent the bolts from coming loose,however, is to stake them in place with a chisel. Mechanical lock prevents it from ever happening.

 

[Armarookie43]

Likely your screws are too short, a lot of aftermarket cases are too shallowly threaded.

The best way to prevent the bolts from coming loose,however, is to stake them in place with a chisel. Mechanical lock prevents it from ever happening.

Or make the hole bigger and put some thicker bolts in there. I always do that with plastic parts in my RC vehicles. But this is metal. After I put thicker bolts, they never come out again (at least in plastic)

 

[djsarma]

The problem is arrmas aluminum diff case. It lacks the 4 keyed pins so the M3.5 diff bolts will take all the load and snap at the head. As others mentioned upgrade to the vitavon V2 diff case, it has 4 pins and M4 screws making it much more durable. Vitavon provided short M4 screws so i used some longer 12.9 grade ones with blue TL as the threads are deep enough.

 

[RCbuzz]

Maybe Arrma just didn't expect a bunch of Rich Duperbash's around here

I had a new 8s diff come with a hole that wasn't threaded all the way into the plastic housing so the screw was sticking out about 2mm and the threads were stripped...

 

[Clubin]

No. I think that I'm going to go with brake cleaner again. I've also tried that too. But I have to keep trying. I'm also going to reduce the power and punch on the XLX2. That should help. TBH, I don't need 12HP. What I need is long term durability and reliability.

Well I have a whole bunch of them just laying around. And I can't buy anything right now since I don't have money. So I have to roll with what I got. Last time I only replaced it the sun gear on one of my Arrma diffs with the same issue and It was OK. How long have you been driving your rig?

Over a year. Haven’t opened diffs up yet. That is a winter thing. 10+ packs through it.