Kraton Kraton front differential advice

[Vanning]

After working on my Kraton's front end tonight, I discovered a few things that possibly could be helpful to some Kraton owners. Mine is the 2016 version if that even matters. This may only pertain to my Kraton as far as I know but maybe it will help others also.

What I read is that some people report blown front diff, cracked gears, or cracked diff gear case etc.

When I first got my Kraton, I pulled it out of the box and started spinning the wheels etc.....I noticed that the front diff felt like it was binding. I didn't think much more but luckily I decided to just take the droop out of the suspension arms at that time. I never thought about it again, until tonight.

Tonight I finished replacing all the bearings in the Kraton with sealed bearings because I run in sand often. I also changed my front diff fluid. The diff spun nice and I felt no binding. I also added some droop or sag back into my A arms. This is when I noticed that the diff would start binding up real bad. Adding droop pushes the dog bones real hard into the output cups of the differential. To fix it....I took the brass collars, that came out of my steering, and put them here (upper and lower)....I had to reset the toe also. The front end is a tiny bit wider but lots of 4x4's are that way. This stopped all binding of my diff and allows for some massive down travel. I could probably go with half the thickness on the collar but it's all I have for now. Maybe I can find some thicker black shims...like the ones that it comes with. Apparently this truck wasn't setup properly from the factory with the shims

 

[chalmene]

Good thinking, I bet you are right about the binding causing my broken gear. I didn't really notice it was binding up till after. I since then have lessened the droop quite a bit with the set-screws and all is smooth. But good idea with the shims if that is eliminating the problem also, will allow for more suspension travel. I'm replacing my bearings with Fast Eddie sealed kit as I go along, just have center and rear diff to go.

 

[Vanning]

I change every single bearing with a Fast Eddie kit for the Kraton also. As for the dog bones in the front, they seem a little too long. With the bronze collars in place, the pin rides on average in the center of the differential output cups. It never binds the front diff through the entire full swing of the A-arms. I set the A-arm adjustment screw so the down travel doesn't yank on the shocks lower ball cup. I stop the suspension a few millimeters before it, hoping not to hammer off the ball cup on the shock rod. I'm also inspecting to see how much wiggle room there is in the dog bones during a big blow to the front end, things may get over extended. As for the rear....there seems to be plenty of wiggle room in the dog bones through the full travel of the A-arms. I have not inspected that 100% yet but only a quick gander at it looked promising.

 

[Vanning]

It looks like I'm keeping the top collar up front and removing the bottom. It gets rid of a little negative camber....keeps the front width the same and should keep my dog bones from jamming up the diff. Can't wait to run it this weekend.

 

[ejimbo4]

After working on my Kraton's front end tonight, I discovered a few things that possibly could be helpful to some Kraton owners. Mine is the 2016 version if that even matters. This may only pertain to my Kraton as far as I know but maybe it will help others also.

What I read is that some people report blown front diff, cracked gears, or cracked diff gear case etc.

When I first got my Kraton, I pulled it out of the box and started spinning the wheels etc.....I noticed that the front diff felt like it was binding. I didn't think much more but luckily I decided to just take the droop out of the suspension arms at that time. I never thought about it again, until tonight.

Tonight I finished replacing all the bearings in the Kraton with sealed bearings because I run in sand often. I also changed my front diff fluid. The diff spun nice and I felt no binding. I also added some droop or sag back into my A arms. This is when I noticed that the diff would start binding up real bad. Adding droop pushes the dog bones real hard into the output cups of the differential. To fix it....I took the brass collars, that came out of my steering, and put them here (upper and lower)....I had to reset the toe also. The front end is a tiny bit wider but lots of 4x4's are that way. This stopped all binding of my diff and allows for some massive down travel. I could probably go with half the thickness on the collar but it's all I have for now. Maybe I can find some thicker black shims...like the ones that it comes with. Apparently this truck wasn't setup properly from the factory with the shims

I am having the same problem and I am trying to figure out what brass collars out of the steering you are talking about?

 

[Vanning]

A Fast Eddie bearing kit comes with bearings for the Kraton's steering. To put in the bearings you have to remove the brass bushings that are in the rods holding the servo saver etc......I used them to fix the binding diff issue since I no longer need them in the steering. If you use them, you will have zero camber but It seems to handle well that way.

 

[ejimbo4]

Cool. I have set of the Fast Eddie's....Appreciate it!!! For now I put a small thick luck washer on each side and snugged them up and it seems to have fixed it so I will try the bushings next when I do my diffs in a couple weeks and have it tore down. See which ones I like better!

 

[Vanning]

I would just keep it as is if it's working... My theory is to have as much thread as possible inside the a-arm but still correct the issue.

 

[CL-Audio]

Man I wish there were more how to wrench video tutorials. I would love to see a video tutorial on how to replace every bearing in the Kraton. There are some I just do not know how to get to. Such as the gearbox. Looks like I have to take everything apart. Without an aid I would take it apart and never be able to get it back together again. This is my first RC so every fix/maintenace job is quite intimidating. Used some vids to figure out differentials so far. Extremely helpful!!

 

[Maxxwrecker07]

I'm glad I found this thread. My front diffs are binding up too. I didn't think to check the driveshafts. I have the team Durango diff cups coming and will report back if shimming is needed.

 

[Kauaiguy]

I'm glad I found this thread. My front diffs are binding up too. I didn't think to check the driveshafts. I have the team Durango diff cups coming and will report back if shimming is needed.

The Durango diff cups are deeper, it should have extra clearance

 

[Vanning]

Keep us posted on the diff cups. Post some good close up pictures.

 

[JasonG]

Great idea.
I noticed the same thing.
I had to take some droop out of the front because it was binding.
Curious how the Durango diff cups would work.

Team associated has some pillow ball shims for the RC8B3
Cannot find any dimensions though.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXFJUU&P=7
Part #: 81072