Diff outdrive cup slop

[PeighDay]

Diff outdrive cup slop

Was replacing my diffs today with the metal diff cups and I stripped the thread on one of the diff bulkhead covers. So I took the whole front end part and thankfully had another diff bulkhead I had ordered.

Noticed with this one though there is a considerable amount of slop on the diff cup. I replaced the bearings the diff outdrive and still has the same slop. I pushed the diff cup as far down as I can to the bearing but it doesn’t want to seat right.

I have read a lot about shimming the outdrive but this seems like a lot of slop to me. I assume I just chalk it up to a faulty manufacturer diff bulkhead and go by myself a HR or another brand. Just wanted to gather input before I spent some money.

 

[Diem Turner]

I noticed that too on my Infraction. I fixed it by pushing the input pinion from the inside and the outdrive cup from the outside before tightening down the grub. Problem solved.

 

[PeighDay]

I noticed that too on my Infraction. I fixed it by pushing the input pinion from the inside and the outdrive cup from the outside before tightening down the grub. Problem solved.

I thought I had already did that but maybe I am not understanding what to do. I am squeezing it together when I am tightening the grub screw but it wants to slide up cause the groove

 

[LicketySplit]

I noticed that too on my Infraction. I fixed it by pushing the input pinion from the inside and the outdrive cup from the outside before tightening down the grub. Problem solved.

What he said.

 

[Diem Turner]

I thought I had already did that but maybe I am not understanding what to do. I am squeezing it together when I am tightening the grub screw but it wants to slide up cause the grooveView attachment 245081

You need to take the diff out, push against the input pinion from the inside, push the cup on from the outside and then tighten down the grub. There's a little bit of wiggle room for the pinion gear to move inside the housing. When you push the cup on from the outside with the diff installed it pushes the pinion into the housing until it butts up against the diff. When you tighten down the grub it can pull back out from the diff to the housing. I hope that makes sense

 

[PeighDay]

You need to take the diff out, push against the input pinion from the inside, push the cup on from the outside and then tighten down the grub. There's a little bit of wiggle room for the pinion gear to move inside the housing. When you push the cup on from the outside with the diff installed it pushes the pinion into the housing until it butts up against the diff. When you tighten down the grub it can pull back out from the diff to the housing. I hope that makes sense

ive taken the whole front end apart. I’m not sure if this is causing the issue. I just tried it again. Still didn’t work

 

[Diem Turner]

Did you take the diff out?

Put on the cup while pushing against the pinion from the inside and then tighten down the grub. Should work. If not, then I'd just put a shim under the drive cup.

 

[PeighDay]

Did you take the diff out?

Put on the cup while pushing against the pinion from the inside and then tighten down the grub. Should work.
View attachment 245083

Yeah took the diff out. Thank you for the diagram. That’s exactly what I am doing to push them together.

 

[Diem Turner]

Yeah took the diff out. Thank you for the diagram. That’s exactly what I am doing to push them together.

That's weird. That did the trick for me. Then I'd just put a shim under the input cup and call it a day.

 

[PeighDay]

That's weird. That did the trick for me. Then I'd just put a shim under the input cup and call it a day.

I’m going to deduce it’s the diff bulkhead. That’s the only thing that is different.

That's weird. That did the trick for me. Then I'd just put a shim under the input cup and call it a day.

okay I will try and find the right size shims. Correct me if I am wrong but its not advised to shims the inside of the diff from the input gear.

edit:
Anybody have any good recommendations for diff bulkheads. Not a big fan of HR and don’t want to have to wait weeks from something from China.

 

[dk3000]

I’m going to deduce it’s the diff bulkhead. That’s the only thing that is different.


okay I will try and find the right size shims. Correct me if I am wrong but its not advised to shims the inside of the diff from the input gear.

edit:
Anybody have any good recommendations for diff bulkheads. Not a big fan of HR and don’t want to have to wait weeks from something from China.

Vitavon only takes like 2 weeks max. Some get it faster. Treal has them, Basherqueen did have them but have not seen them listed for some time. I really like Vitavon stuff and have 2 HR bulkheads and 3 Vitavon. No issues with either

 

[Diem Turner]

I’m going to deduce it’s the diff bulkhead. That’s the only thing that is different.


okay I will try and find the right size shims. Correct me if I am wrong but its not advised to shims the inside of the diff from the input gear.

edit:
Anybody have any good recommendations for diff bulkheads. Not a big fan of HR and don’t want to have to wait weeks from something from China.

That's my understanding as they get eaten up by the input pinion. Unless you use 13x19mm shims. I was just reading that yesterday in another thread.

 

[PeighDay]

Vitavon only takes like 2 weeks max. Some get it faster. Treal has them, Basherqueen did have them but have not seen them listed for some time. I really like Vitavon stuff and have 2 HR bulkheads and 3 Vitavon. No issues with either

That’s my problem. I don’t even want to wait two weeks. I know, first world problems. The weather is perfect right now and I want to bash.

That's my understanding as they get eaten up by the input pinion. Unless you use 13x19mm shims. I was just reading that yesterday in another thread.

Thank you for that info.
I think I may have found the issue.

 

[Diem Turner]

That’s my problem. I don’t even want to wait two weeks. I know, first world problems. The weather is perfect right now and I want to bash.

Thank you for that info.
I think I may have found the issue.

Right on, glad you were able to track down the issue. Which poses the question...what's different? Is it possible that the ground down section of the shaft doesn't go far enough toward the gear end which keeps the drive cup a little further away from the bulkhead? Kind of hard to describe in words what I mean, I hope this makes sense.

I'm talking about the shoulder where the arrow is pointing to. If that sticks out a little further then you can't push the cup down far enough as the grub screw will pull it forward. Again, I hope this makes any sort of sense

 

[PeighDay]

Right on, glad you were able to track down the issue. Which poses the question...what's different? Is it possible that the ground down section of the shaft doesn't go far enough toward the gear end which keeps the drive cup a little further away from the bulkhead? Kind of hard to describe in words what I mean, I hope this makes sense.

I'm talking about the shoulder where the arrow is pointing to. If that sticks out a little further then you can't push the cup down far enough as the grub screw will pull it forward. Again, I hope this makes any sort of sense
View attachment 245118

Yes that totally makes sense.

you can see from this photo that there is not enough ground down section as you put it. When I tighten down the grub screw it slides down the diff cup away from the diff housing.

 

[Diem Turner]

Yes that totally makes sense.

you can see from this photo that there is not enough ground down section as you put it. When I tighten down the grub screw it slides down the diff cup away from the diff housing.


View attachment 245122

Yeah, I think you've solved the case.

 

[PeighDay]

Yeah, I think you've solved the case.

I noticed the GP4 markings are different. The ones I have seen from the Arrma website have the gp4 near the gear. The bottom one is the one I got from JennysRC That doesn’t fit right.

 

[PeighDay]

So my dumb@$$ realized there is a shim on the inside of the main input gear. Thankfully shouldn’t be to hard to add since I just need to loosen the drive cup on the back side.

I was kind of shocked when I saw this as most people don’t recommend adding shims between the main input gear and the bearing.

Also noticed the shim is only for the Talion and Outcast and not listed on the Kraton EXB or Mojave EXB.

 

[dk3000]

Let us know how that goes

 

[PeighDay]

Let us know how that goes

Took the front end apart again just to make sure I had everything right. It definitely felt like it needed a shim behind there. Once I did that it felt really nice.

put everything back together the mesh wasn't as tight as shown in the video was pretty close to it.