Kraton Kraton 6s pinion gear help. Keeps coming loose even with red thread lock. Diff oil too thick?

[Custnam]

Hello again forum. Well my 12T pinion keeps coming loose on my Kraton despite using red permatex. The first time it happened it damaged the set screw so bad I had to drill it out just to get it off. Well it also slightly damaged one of the edges on the spur so it runs loud now. Anyway I am in the process of getting a new pinion, spur, and sliding motor mount but in the mean time I could use some help. This seemed to start happening after I switched the stock diff oils to thicker. I am currently running a mix of 80k and 60K in the front to get close to 70K. And the center has 500K, and the rear has a mix of 30 and 60 to get close to 50K. Do you think the thicker oils (specifically the centers 500K) could be causing this? Like I said I am using a good amount of red thread lock and letting it sit for 24 hours. But within 5-10 minutes of running it always comes loose. It just happened again. Ive read several other posts with people using 500K in the center with no issues so I am not sure what they are doing differently? I am going to go back to lighter weights and see if that helps. Most likely 60K front, 200K center, and 30K rear which is what I ran in in my Notorious and I don't recall this happening with that, so maybe thats the key. Anyway like I said Im getting a new spur and pinion hopefully soon, but just thought Id post this and see what you all think. Thank you!!

PS: Im running at level 5 punch.

 

[Engineer]

What tool are you using to tighten the set screw on the pinion and are you running the screw all the way to clean out and residual Loctite that may have been previously there?

 

[Custnam]

What tool are you using to tighten the set screw on the pinion and are you running the screw all the way to clean out and residual Loctite that may have been previously there?

Im using a 2mm driver Ive had for years. And yes Im cleaning out all old thread lock and even using a new set screw since I have a pack of 50 12.9s.

 

[FlipSide]

I recently had the same problem. I was just lazy and only adding more locktite, but it kept coming loose.

I solved the problem by thoroughly cleaning the pinion and set screw with brake cleaner and making sure to remove all the old locktite before applying new locktite.

While the pinion is removed from the motor shaft, make sure the threads are good and you can thread the set screw all the way in.

 

[Arrma15T68]

I have 1 million in my centre diff on a Notorious. I apply plenty of locative but this time I let it dry for at least a full 24 hrs and then ease onto the throttle. No problem thereafter. “Good lock” ! By the way it was a 20 to other.

 

[abracing]

...clean everything spotless, with brake clean, include motor shaft..blue loctite on grub, plus motor shaft !!..l have had no problems at over 100mph. With the limitless..

 

[jondilly1974]

Im using a 2mm driver Ive had for years. And yes Im cleaning out all old thread lock and even using a new set screw since I have a pack of 50 12.9s.

How long are you letting it cure? Maybe you have a bad tube of TL

 

[Engineer]

You mentioned that you had to drill out the set screw the first time - could you have damaged/removed some of the threads in the pinion so the set screw engagement isn't as good? Might be worth just getting a new pinion to try out. I'm a fan of the Tekno M5 pinions

 

[Custnam]

You mentioned that you had to drill out the set screw the first time - could you have damaged/removed some of the threads in the pinion so the set screw engagement isn't as good? Might be worth just getting a new pinion to try out. I'm a fan of the Tekno M5 pinions

Yes it destroyed that pinion so I replaced it.

How long are you letting it cure? Maybe you have a bad tube of TL

About 24 hours. I just redid it with a new screw, more thread lock, and cleaned threads. Im also redoing the diffs with the same weights I had used in my Notorious. 60k F, 200k C, 60k R.

 

[Spoc85]

Ensure the grub screw is making contact with the flat part of the shaft before tightening.
There’s also a second hole in the pinion to install another grub screw for good measure.
Weights of the fluids will have zero to do with the pinion coming loose. Follow the suggested instructions and the pinion shouldn’t move?

 

[Soppy]

With the pinion off run the screw in as far as it will go and make sure that it goes in at least 1/2 way through the into the shaft hole of the pinion. When you put the pinion back on the motor , make sure it will turn freely on the shaft with no binding. Insert the set screw and make sure it seats on the flat portion of the shaft by by slightly tightening the pinion then backing off on the setscrew and tightening again. To speed the curing of the thread locker, you can apply some heat from a heat gun or small torch. You want to keep the temperature or the pinion below 250 deg. I'm running 500 weight in my center diff with no problems.

 

[PirateRC]

I know this will sound doggie but, after setting your pinion gear in, dap a small amount of Tarzan grip supper glue on the outside end only. It is possible to break the super glues bond with a couple of taps with a tac hammer ?

 

[Custnam]

Thanks for all the suggestions. This is one of the many reasons I came back to Arrma and Arrma forum. Half my decision was this forum and its members. Yesterday I redid everything with 2 set screws, red loctite on clean threads with new set screws. I also went back to 60k F, 200k C, and 30k R. So I am hoping I finally got it.

PS: Horizon is sending me a new spur, pinion, and and mount. Because even before the screw backs out the spur is very loud since the first time it came loose the pinion damaged one of the edges of the spur. Not so bad that it doesn't work, but enough for it to not sound "right". I also just ordered and received a brand new motor and another sliding mount from JRC. So when I get the new spur and pinion Ill be installing it all with new parts. The current motor works, but like I said in another thread I slightly damaged the motor shaft to get the old ruined pinion off.

PS: @jondilly1974 . Are you sure you arent a forum bot? Because I swear within 30 seconds of me posting anywhere on the forum I get a like notification from you. Kidding of course, sorta. 30,29, 28.....

 

[Custnam]

Guys I am getting super frustrated with this damn pinion issue. Ive tried everything I can think of to get it to stop coming loose. Red thread lock, orange thread lock, lighter diff fluids, using both set screws, waiting well over 24 hours for it to dry and no matter what I cant get through a single run without it coming loose. And it just ruined another brand new sliding motor plate I just bought! The thread lock I am using is the same I use on my Outcast 4s, and the orange I have is the same I used on my Notorious when I had it and that did not have this issue. Im not sure what else to do? Is red gel permatex no good? I am getting sick of ruining the slider plates everytime the pinion slides so Im assuming the solution to that is the HR one? Is the motor shaft hole on the HR one large enough to use a 13-14T pinion without getting shredded if the pinion comes loose again?

My last idea is some different red thread lock. Ive read several threads on here with people only using blue and not having this happen, so what am I doing differently? Is it maybe that I run on asphalt and have heavier diff fluids that adds more stress to the set screw? Im currently running 80K F, 500K C, and 60K R. But this also happened when I ran 60K front, 200K C, and 30K R. Anyway Id appreciate any more advice or ideas. This is getting ridiculous. I have a new 12T pinion and spur on the way so I am hoping to get this sorted before I get those. Because this issue is what messed up my current spur and if it happens again and another spur gets damaged due to a loose pinion Ill be sticking a stick of dynamite in this and running it off a bridge as I gleefully watch it explode before hitting the ground!

 

[Custnam]

Ok. Well I just ordered the HR AON38M01 mount and a Tekno 13T pinion TKR4173, as well as some high temp brand name Loctite red. Im hoping this finally solves this issue. Other than this one issue Im loving this truck. So much power and handles AMAZING!!

 

[Spoc85]

What are you using to tighten up the grub screws?

 

[Surchaufeur]

If it was me i would have flooded the dam thing lol. My red threadlock is from permatex and i never really have anything come undone while using it. But the diff outdrive loves to slightly slide out causing in and out play but the screw is still fully locked in. I tried today to tighten it up the best i could and i stripped the hex a big snap. I got rid of the save D sleeve because i only had grub screws who were shorter.

Flood it! wprth a try i guess. But to remove it afterward oh boy. Maybe your threadlock is just not good anymore? Because threadlock even red should old i rarely clean sccrews i only wipe them off with paper towel to remove the most nasty stuff i can and thats pretty much it?‍. Always sticks quite hard but i don't get the typical snap when i get the screw loose. Something is wrong with the threadlock you have. Is the liquid somewhat clear or opake like milk? Change grub screws and remember the stock pinion has 2 grub screw holes wont hurt i guess to use 2. Well the stock pinion on my exb was like that

Ok. Well I just ordered the HR AON38M01 mount and a Tekno 13T pinion TKR4173, as well as some high temp brand name Loctite red. Im hoping this finally solves this issue. Other than this one issue Im loving this truck. So much power and handles AMAZING!!

Whats your oils? How is your motor shalf look like?

 

[Custnam]

What are you using to tighten up the grub screws?

A high quality 2mm driver Ive had for years.

 

[Surchaufeur]

Why did you order the hot racing adjustable mount?the v4 is superior. You just bought a motor mount who removes your easy acess diff feature. And might not be compatible with the hot racing center cover you have now. You are downgrading instead of upgrading the motor mount has nothing to do with your pinion getting loose. Or you messed up the part number

 

[Custnam]

Why did you order the hot racing adjustable mount?the v4 is superior. You just bought a motor mount who removes your easy acess diff feature. And might not be compatible with the hot racing center cover you have now. You are downgrading instead of upgrading the motor mount has nothing to do with your pinion getting loose. Or you messed up the part number

The reason was because I was tired of the pinion ruining the sliding motor mount part every time it gets loose. Im looking for a mount that has a motor shaft hole large enough that if the pinion slides it doesn't rub on the mount and trash it. I was hoping to find a mount that has a larger shaft hole where the pinion wont hit it if it comes loose and slides down the motor shaft. See pic for what I mean.