Kraton Stripped out front differential case Kraton V4

[GutterMan]

I installed the RPM rear skid plate and the front skid plate/ bumper and took it for a test run today. Today was my 3rd battery through the truck. Unfortunately one of the front screws on the new bumper popped out and won't tighten back in. I could be wrong but it looks like two of the holes on the front diff case have metal threads and two have plastic but I wasn't able to see very well. The RPM bumper has a lot of room to flex before it hits the stock bumper, so i'm guessing when I landed hard it acted as a pry bar and pulled the screw right through the threads. I have now added a make shift spring between the new bumper and the old bumper to reduce the flex.

For now I just put some glue on the screw going into the problem hole and the other 3 are nice and tight. Do I buy a bigger screw for the problem hole or do I replace the case? Any advice would be great, I am still a novice at repairing these things but i'm learning one break at a time.

 

[bicketybam]

I installed the RPM rear skid plate and the front skid plate/ bumper and took it for a test run today. Today was my 3rd battery through the truck. Unfortunately one of the front screws on the new bumper popped out and won't tighten back in. I could be wrong but it looks like two of the holes on the front diff case have metal threads and two have plastic but I wasn't able to see very well. The RPM bumper has a lot of room to flex before it hits the stock bumper, so i'm guessing when I landed hard it acted as a pry bar and pulled the screw right through the threads. I have now added a make shift spring between the new bumper and the old bumper to reduce the flex.

For now I just put some glue on the screw going into the problem hole and the other 3 are nice and tight. Do I buy a bigger screw for the problem hole or do I replace the case? Any advice would be great, I am still a novice at repairing these things but i'm learning one break at a time.

Did you reuse the stock screws when you added the RPM bumper? Is so, too short. You need something longer. Personally I would get the small Typhon bumper that holds the hinge pins in and ditch the stock bumper.

 

[GutterMan]

I made sure to use the longer ones. I will look into the Typhon bumper but won't I still need to fasten into the same hole? Or does that design make it so I no longer need to use the stripped hole? Thanks!

OK I watched some videos of the T bone racing bumper going on and looks like it just covers up the screw that im having issues with so that sounds like a great idea. I will order up a nicer bumper and it sounds like that resolves the issue, making it so I no longer have to fasten into that hole.

 

[bicketybam]

I made sure to use the longer ones. I will look into the Typhon bumper but won't I still need to fasten into the same hole? Or does that design make it so I no longer need to use the stripped hole? Thanks!

OK I watched some videos of the T bone racing bumper going on and looks like it just covers up the screw that im having issues with so that sounds like a great idea. I will order up a nicer bumper and it sounds like that resolves the issue, making it so I no longer have to fasten into that hole.

You still need to use the hole. Sorry for not being clearer.

 

[Notorious J]

I installed the RPM rear skid plate and the front skid plate/ bumper and took it for a test run today. Today was my 3rd battery through the truck. Unfortunately one of the front screws on the new bumper popped out and won't tighten back in. I could be wrong but it looks like two of the holes on the front diff case have metal threads and two have plastic but I wasn't able to see very well. The RPM bumper has a lot of room to flex before it hits the stock bumper, so i'm guessing when I landed hard it acted as a pry bar and pulled the screw right through the threads. I have now added a make shift spring between the new bumper and the old bumper to reduce the flex.

For now I just put some glue on the screw going into the problem hole and the other 3 are nice and tight. Do I buy a bigger screw for the problem hole or do I replace the case? Any advice would be great, I am still a novice at repairing these things but i'm learning one break at a time.

View attachment 35843

All the holes in the dif case are plastic, so once stripped, hard to get anything to stay. Sometimes a little CA (crazy glue) will work to hold a screw in temporarily, but a new case is probably a good investment. I don't have an RPM bumper, so it's hard to understand exactly what happened. When you run into problems like these, it's a good idea to take photos of the problem area.

 

[GutterMan]

Ok, well a new diff case doesn't seem too bad. I've never swapped one out before but I'll have to figure it out eventually.

 

[roondog]

I ran mine today and at the end of my bashing I noticed a screw sticking out under the RPM bumper. Mine did the same. It's stripped. It was a front screw.

 

[GutterMan]

I ran mine today and at the end of my bashing I noticed a screw sticking out under the RPM bumper. Mine did the same. It's stripped. It was a front screw.

I think that bumper is flawed in it's design for that very reason. The empty space between the old and new bumper in the front cause it to act like a pry bar when you hit something or take a nose dive. I watched the installation of the T-bone racing bumper going on and it looks like it attaches behind and in front of those two front screws... possibly making it not matter if one is stripped? I will have to snap a picture of what I mean, but it sounds like ours both did the exact same thing.

 

[GutterMan]

Here are some more pictures of mine. I rolled a strip of aluminum and jammed it in the empty space and put screws through the front of the bumper to hold it. It won't be flexing as much now but i'm probably going to get a different bumper and then attempt to switch out the diff case when I build up the courage.

 

[GutterMan]

I'm also trying to design a full bottom skid plate that I can just slip on and screw to the sides of the tray and probably fasten to the front bumper. Once I get the shape right I will be able to just cut a new one in 5 minutes whenever it tears off or wears through. I have unlimited access to aluminum coils in all different colors.

 

[roondog]

Surely others have used RPM on previous Kraton versions. There isn't any change with the front from V3 to V4 right? At least that is what I gather.

 

[GutterMan]

Surely others have used RPM on previous Kraton versions. There isn't any change with the front from V3 to V4 right? At least that is what I gather.

I'm not 100% sure if there is a difference or not, and I think it would be perfectly fine if the threads were metal. I wasn't doing 30 foot jumps when this happened either, I was just doing some small jumps on a grassy hill. Have you decided what you are going to do to fix yours?

 

[roondog]

I ordered a new case. I'll swap it out. Not sure what I want to do for bumper though. I wasn't super jumping either but I did have a couple lawn darts and front end landings.

 

[GutterMan]

This is the bumper I was looking at, if you watch the video it shows that they fasten this one to a new pin block on the top and bottom and then the plate covers those two front screws and fastens to the rear ones that I haven't had an issue with yet. To me it seems like I could wait on changing out the diff case but i'll probably order one up so it's ready to go.
https://tboneracing.net/collections...asher-front-bumper-arrma-kraton-6s-v2-v3-2018

 

[roondog]

Not a fan of how it looks. He makes some good stuff, but a good deal of it is hideous. It may be a better design than rpm though. I use one on my daughter's fazon. She couldn't care less, but I think it's hideous.

 

[GutterMan]

I ordered a new case. I'll swap it out. Not sure what I want to do for bumper though. I wasn't super jumping either but I did have a couple lawn darts and front end landings.

Did you buy the same one or did you get an upgraded case?

 

[roondog]

I went with stock for now.

 

[Soppy]

I think that bumper is flawed in it's design for that very reason. The empty space between the old and new bumper in the front cause it to act like a pry bar when you hit something or take a nose dive. I watched the installation of the T-bone racing bumper going on and it looks like it attaches behind and in front of those two front screws... possibly making it not matter if one is stripped? I will have to snap a picture of what I mean, but it sounds like ours both did the exact same thing.

On my V3 , I took my old bumper off and removed the bottom portion with a belt sander. That way the new RPM bumper sits flat with no space and the old front bumper still fits with the 2 screws on the front.

 

[GutterMan]

On my V3 , I took my old bumper off and removed the bottom portion with a belt sander. That way the new RPM bumper sits flat with no space and the old front bumper still fits with the 2 screws on the front.

Good idea. I'm going to try one of t-bone racing bumpers for now. It does seem kind of big and ugly but i'm shooting for durability and I can always pull the grinder out and reshape it.

 

[GutterMan]

Has anyone tried the HR diff case? I just don't want to pop the same one back in and strip it out again, but I guess if i'm running the new bumper to the pin block I won't be putting stress on that area anymore.