Help! My Kraton 6sV4 has been making an aweful grinding noise.

[Lumberjack7]

I've rebuilt the center diff and rear diff. I'm going to look at front diff but I have taken this thing apart and put back together way more then I've been able to use it. The shop I bought it from has been useless. Any help, thoughts, or remedies would be greatly appreciated.

 

[gotnitro]

Sounds like you've made yourself some gear salad. Time to take it back apart.

 

[Lumberjack7]

Sounds like you've made yourself some gear salad. Time to take it back apart.

Yes I have done all that and I just took apart the front diff and all appears ok.
I can take everything apart but I don't know what else to look for at this point

 

[gotnitro]

Something is bad somewhere. Put your ear to it while someone else pulls the throttle to figure out exactly where its coming from, then start opening things back up.

 

[ph47mf]

i would stick that on a stand with the wheels off the ground and pull the trigger slowly to see where it's coming from, that sounds like the diff alright.

 

[3d-rc.myshopify.com]

Crown and pinion gear. They can look fine and be bad at same time. I have seen them do that and take 2 shims on the crown side and be completely fine after.

 

[Lumberjack7]

I took out all the diffs and replaced the rear input drive gear. Put it back together and it ran good for two minutes then the same noise came back. Going to reinspect but I'm ready to throw this thing in the trash!

 

[3d-rc.myshopify.com]

Did you shim the diff housing? If not I will gladly walk you through it. don't give up on it. Once you figure the little things out it's a blast.

 

[jtself42]

No don’t trash it! ? I dealt with diff issues for a while. I would pull them apart, throw it back together and it would run great, for a few minutes like you said and then it would come back again someone on this forum told me to hold the back end off the ground while pressing down on the front, then give it throttle. Then do the same for the front and press on the rear, you should be able to pinpoint from there if it’s front or rear. For me, it sounded like this and it was ring and pinion every time.

 

[Lumberjack7]

Did you shim the diff housing? If not I will gladly walk you through it. don't give up on it. Once you figure the little things out it's a blast.

Yes.... When you talk about shims you mean these? If so, I used one on each gear

 

[3d-rc.myshopify.com]

Yes.... When you talk about shims you mean these? If so, I used one on each gear

View attachment 109405

Nope actually shimming the housing itself that it goes into. 1 sec I will find a video for you

 

[jondilly1974]

Yes.... When you talk about shims you mean these? If so, I used one on each gear

View attachment 109405

You need to grab the diff output cups when it’s inserted into the diff housing and check for side to side play. You can also check the gear mesh from the hole in the bottom of the housing. You want the least amount of slop between the diff pinion and ring gear. You will need to add shims outside the bearing on the ring gear side. This will push the ring gear closer to the pinion, preventing the damage you’re having.

 

[3d-rc.myshopify.com]

I shim behind the pinion bearings as well. The pinion is usually .3mm off from where it should be.

 

[SrC]

@Lovestricken you don't play around. You are the shim king. Agree

 

[jondilly1974]

I shim behind the pinion bearings as well. The pinion is usually 3mm off from where it should be.

I’ve always been able to shim the output cup enough to get the proper backlash. Is there an extreme time when you couldn’t just shim the output and get it close enough?

 

[3d-rc.myshopify.com]

Yes most every time. Next time you put 1 in paint the crown gear and check where it wears. Its only about a 1/3 on the crown. I started to realize when I would blow out pinion and crown gears half the crown area was still perfect. I actually just noticed that this last diff building. Let's me see if I can get a stock pic
Well I see the exb is almost right on the housing.. they fixed that part. I don't have a diff housing I haven't shimmed yet. These are what I use behind the bearing

 

[Lumberjack7]

I pulled everything apart, shimmed the input gear but it's still making a noise and it seemed to be coming from there center. Pulled center diff apart shimmed that a little and it's still making the aweful clacking noise any time any torque is applied. I can hold it in the air and it purrs but as soon as I put it on the ground something is off. I pulled the motor off and it appears fine and runs normally when not attached to the center diff. Still at a loss ?

 

[arrma6snewbie]

I’m new to the arrma but how’s your gear mesh from the motor to the center diff. Also are the bolt tight holding down your center diff.