Kraton Bigger pinion

[martysmith223]

I was afraid of that. I thought it looked good too, but while driving I'd here a frequent crack sound. Could it be one of the diff. They're probably about due for a relube, but I didn't think it'd tell me by being so loud. I check temps on the p/s and it was 150F at the end of the run. It's a 14T pinion on a Kraton and I was bashing. Moror temps stayed right at 140F the whole run. BTW, it drove fine except for the subtle cracking sound. Sound familiar to anyone??? Advice / help much appreciated!

it's one of your diffs if I'm not mistaken I cant be for sure cause im not there but mine do it about the time one of my diffs are about to go normally comes from the sun gear on my setup

 

[Notorious J]

Pop Quiz: in the picture attached, what kind of mesh is shown?
A) too tight
B) too loose
C) just right
View attachment 37433

Too loose

 

[bicketybam]

I set mesh by feel. With the wheels off the ground I wiggle the spur from underneath and see how much lash there is with the pinion. I can't go just by looks.

 

[Wmorgan]

I set mesh by feel. With the wheels off the ground I wiggle the spur from underneath and see how much lash there is with the pinion. I can't go just by looks.

I do the same by feel and that pic I shared was after loosening a tad. I was still hearing the cracking sound so I was sure it wasn't the mesh, but I thought I'd share here and see what y'all thought. Most said it looked good and some say loose. That's about as loose as I'm comfortable with. After researching more and marttysmith223 suggested I'm certain it's the center diff and that's where I could here the cracking. So, it's time!! This will be my first diff rebuild! ?. Going to just do them all while I'm at it. ?
I'm thinking 500k center, 60k rear, 30k front.

 

[joostin420]

currently I run 60/200/30k front/center/rear.

 

[L0stB1t]

I'm thinking 500k center, 60k rear, 30k front.

You should put the heavier weight (60k) in the front and the lighter one (30k) in the rear. Otherwise the car won't turn as sharply.

 

[Wmorgan]

You should put the heavier weight (60k) in the front and the lighter one (30k) in the rear. Otherwise the car won't turn as sharply.

That's the advice I need. Lacking experience with diffs and the various lube options that are available. This will be fun to experiment, but want to at least get started on the right track. I also have some 1M silicone that I'll try eventually.

 

[Wmorgan]

So went to change center diff and to check gears and discovered that the spider gear guide blocks were jammed into the side wall of the bell. Can't remove gears at all. See picture below.
Anyone ever seen this? What could have caused this?
They're all jammed following the same rotation it appears. You can see a gap on the same side of each block as well as they're all buried into the opposite wall. Any help, advice, explanation is greatly appreciated.
BTW...called Horizon and they're sending me a new center diff so good on them for backing the product.

 

[Mr.Duke]

It appears that excessive heat builtup within the diff caused the plastic to become hot enough to deform while allowing the end blocks to rotate out of position while the plastic was soft. Once the plastic cooled off the blocks became lodged in the side of the cup.

 

[Dakota]

You should put the heavier weight (60k) in the front and the lighter one (30k) in the rear. Otherwise the car won't turn as sharply.

So if I was going to do 50/200/20 should i put the 50 in the front and 20 in the rear ??

 

[Wmorgan]

It appears that excessive heat builtup within the diff caused the plastic to become hot enough to deform while allowing the end blocks to rotate out of position while the plastic was soft. Once the plastic cooled off the blocks became lodged in the side of the cup.

Makes since. Question now is why did it get hot? When I opened the diff it appeared to be filled with some kind of grease and wasn't overly full. Likely a lack of lubricant allowed excessive heat. I did put a 14T pinion on which may of been too much for the lube condition. Lesson learned is to go ahead and replace factory diff lube if making changes that might increase heat or wear.
Picture of factory diff lube when I opened it. Some kind of gray grease.

 

[Mr.Duke]

Makes since. Question now is why did it get hot? When I opened the diff it appeared to be filled with some kind of grease and wasn't overly full. Likely a lack of lubricant allowed excessive heat. I did put a 14T pinion on which may of been too much for the lube condition. Lesson learned is to go ahead and replace factory diff lube if making changes that might increase heat or wear.
Picture of factory diff lube when I opened it. Some kind of gray grease.View attachment 37564

If you can get the guts out and clean all the metal parts up with brake cleaner there should be a good heat signature present to help indicate to highest point of friction

 

[LibertyMKiii]

My Kraton v4 has been making a whining sound after a few packs using the 15T pinion. ( the specific pinion does not have anything to do with it) I have extensive experience with MOD 1 gears and setting the wiggle room between the mesh.

Probably has 4 packs total time on the RC (2 outings with 4s and 2 outings with 6s)

I suspect the center diff on mine also, but it still functions normally. I put the truck on the ground and lifted the front wheels hit the throttle, then the same procedure with the rear wheels, and finally left to right. All diffs are working as normal.

For now I have decided to see what it does and if it gets worse.

 

[L0stB1t]

So if I was going to do 50/200/20 should i put the 50 in the front and 20 in the rear ??

Yes, that would be the best choice. If you would put heavy oil in the rear, the wheel on the inside of a turn wants to go just as fast as the one on the outside, pushing the car straight on, especially when the front has bad traction (e.g. during acceleration).

I'm using 30k in the rear and I think it shouldn't be heavier than that unless you "need" it for things like hill climbing or plowing through mud. In the front there's 50k and I think people use up to 100k. I'm happy with 300k in the center but here's a great tread where people prefer heavier weights: https://www.arrmaforum.com/threads/1-million-wt-diff-oil.7231/

 

[Wmorgan]

My Kraton v4 has been making a whining sound after a few packs using the 15T pinion. ( the specific pinion does not have anything to do with it) I have extensive experience with MOD 1 gears and setting the wiggle room between the mesh.

Probably has 4 packs total time on the RC (2 outings with 4s and 2 outings with 6s)

I suspect the center diff on mine also, but it still functions normally. I put the truck on the ground and lifted the front wheels hit the throttle, then the same procedure with the rear wheels, and finally left to right. All diffs are working as normal.

For now I have decided to see what it does and if it gets worse.

Makes since. Question now is why did it get hot? When I opened the diff it appeared to be filled with some kind of grease and wasn't overly full. Likely a lack of lubricant allowed excessive heat. I did put a 14T pinion on which may of been too much for the lube condition. Lesson learned is to go ahead and replace factory diff lube if making changes that might increase heat or wear.
Picture of factory diff lube when I opened it. Some kind of gray grease.

Sounds similar to my situation. My Kraton ran fine as well. I just didn't like the sound and noticed the P/S was very hot. I could've kept running it. However, I decided it was about maintenance time anyways and the diff was stock. Review my pics and you'll see what was in mine. It wasn't very full and looked like some kind of grease. Resulted in overheating and the bell actually became soft and gear shoes became embedded in the side wall. I'm now motivated to change out diff oils now and on any new vehicle I get...well, at least before I start modifying performance items that add stress. Up until I changed the pinion gear I had 0 issues.

 

[LibertyMKiii]

Sounds similar to my situation. My Kraton ran fine as well. I just didn't like the sound and noticed the P/S was very hot. I could've kept running it. However, I decided it was about maintenance time anyways and the diff was stock. Review my pics and you'll see what was in mine. It wasn't very full and looked like some kind of grease. Resulted in overheating and the bell actually became soft and gear shoes became embedded in the side wall. I'm now motivated to change out diff oils now and on any new vehicle I get...well, at least before I start modifying performance items that add stress. Up until I changed the pinion gear I had 0 issues.

I'm planning on changing the center diff oil to something significantly higher since I like speed and wheelies. Just gotta find motivation to get in the garage and do it. I suspect I will see something similar to your images. I suppose there is always aluminum diff cups as an upgrade for strength and some added cooling benefits.

 

[olds97_lss]

Pop Quiz: in the picture attached, what kind of mesh is shown?
A) too tight
B) too loose
C) just right
View attachment 37433

No clue. I do my mesh by feel. Needs a tick of play. Looking at it, jamming paper in it... never works for me. Need to hold the pinion and rock the spur to feel the play.

 

[Success LiPo]

Awesome thanks guy I will loosen the screws and make sure their is a little gap between the teeth but not too much ..
I think I might have them to close right now

What I would do is get one sheet of notebook paper, put it between the Pinon and the spur gear, then push the sliding motor mount all the way in. Hold the motor tight while you tighten the screw in place, then turn the vehicle over and spin the spur gear from underneath until the paper Ejects. I spent about a year breaking all kinds of pinion gears because I wasn’t very good at setting the gear mesh, and I found a notebook paper trick works like a charm

 

[Dakota]

What I would do is get one sheet of notebook paper, put it between the Pinon and the spur gear, then push the sliding motor mount all the way in. Hold the motor tight while you tighten the screw in place, then turn the vehicle over and spin the spur gear from underneath until the paper Ejects. I spent about a year breaking all kinds of pinion gears because I wasn’t very good at setting the gear mesh, and I found a notebook paper trick works like a charm

I did that didn’t think it was very good .. then eye balled it ran thru two 40 min packs with no issues

 

[thegunsmith]

I did that didn’t think it was very good .. then eye balled it ran thru two 40 min packs with no issues

WOW one pack lasts you 40 mins!? What batteries are you running? I get about 20 minutes per pack