Outcast Front axles pops out from diff cups

[JMS RC]

Some medium hard Outcast bashing today, nice warm weather, halfway through he packs the left front axle popped out, put it back same thing again, adjusted the shocks, the steering rate on the transmitter, droop screws, popped again. Removed the shims on the arm by the pillow balls, then the right front axle popped out. Removing the shims seemed to help on the left side, moving the axle a little bit closer to the the diff cup. Also the front end seems extremely flexible due to the very warm weather, first time this happens to me. Is this a known problem ?

 

[JMS RC]

Pic of the right side, took it apart thinking something must be bent, everything seems fine and axles are straight. Would be nice to solve this before the RPM arms go on there, or if the RPM arms are the solution ? Less Flex ?

 

[Snoprosledneck88]

Pic of the right side, took it apart thinking something must be bent, everything seems fine and axles are straight. Would be nice to solve this before the RPM arms go on there, or if the RPM arms are the solution ? Less Flex ?

View attachment 20769

I have only had this happen once. I don’t think RPM arms would be the “answer” only because the usually flex more, which is why they don’t break as often. IMO. When this happened to me I had rpm arms on. Chassis brace in the front tight?

 

[RxMonkey]

Funny to see this posted. I’ve had my outcast longest of all my arrmas (since April). This just happened to me last outing. I just ran my other trucks and haven’t even looked into it. I was puzzled because it seems like that bone is buried in the cup a good ways. Not like it barely reaches. Can’t understand how it could make it’s way out. The slow motion videos I’ve made show a good bit of flex when these trucks land.

I’ll let you know if I can find a cause. I’m doubtful I will though.

 

[JMS RC]

I have only had this happen once. I don’t think RPM arms would be the “answer” only because the usually flex more, which is why they don’t break as often. IMO. When this happened to me I had rpm arms on. Chassis brace in the front tight?

Funny to see this posted. I’ve had my outcast longest of all my arrmas (since April). This just happened to me last outing. I just ran my other trucks and haven’t even looked into it. I was puzzled because it seems like that bone is buried in the cup a good ways. Not like it barely reaches. Can’t understand how it could make it’s way out. The slow motion videos I’ve made show a good bit of flex when these trucks land.

I’ll let you know if I can find a cause. I’m doubtful I will though.

Been searching about for this and it doesn't seem to be a known issue or common problem. On the E-Revo 2 they have had some problems with the rear axles popping/slipping and they seem to solve this with a added stiffer chassi brace. I did check my chassibraces and they're tightened down. Would be nice if the RPM were the answer but I guess not, you're right they do flex as well. Would be nice though to find a solution before I install the RPM arms since when the driveshaft pops/slips it kinda messes up the arms.

Like I wrote I removed the shims for the pillowball on the arms on the left side and that did seem to help (moving axle/dog bone closer to cup) but it would be nice to keep those shims.

Looked at some photos I took before the right side popped/slipped out, I thought the axles popped on landing but this picture shows that on mine it popped/slipped going up the jump, you can clearly see on the picture that the right wheel is locked.

Found this older thread where Rich Duperbash did have the same problem
https://www.arrmaforum.com/threads/help-with-slipped-cvd-driveshaft.2804/#post-27682
I have asked there if he found the cause, the solution seems to be deeper drive cups which seems logical.

 

[Rich Duperbash]

Been searching about for this and it doesn't seem to be a known issue or common problem. On the E-Revo 2 they have had some problems with the rear axles popping/slipping and they seem to solve this with a added stiffer chassi brace. I did check my chassibraces and they're tightened down. Would be nice if the RPM were the answer but I guess not, you're right they do flex as well. Would be nice though to find a solution before I install the RPM arms since when the driveshaft pops/slips it kinda messes up the arms.

Like I wrote I removed the shims for the pillowball on the arms on the left side and that did seem to help (moving axle/dog bone closer to cup) but it would be nice to keep those shims.

Looked at some photos I took before the right side popped/slipped out, I thought the axles popped on landing but this picture shows that on mine it popped/slipped going up the jump, you can clearly see on the picture that the right wheel is locked.

Found this older thread where Rich Duperbash did have the same problem
https://www.arrmaforum.com/threads/help-with-slipped-cvd-driveshaft.2804/#post-27682
I have asked there if he found the cause, the solution seems to be deeper drive cups which seems logical.

It will tend to happen going off abrupt jump faces and on harder uneven landings where one side is forced upward more than the rigs regular range of motion. Shock limiters might be a solution or possibly grinding the arms a tiny bit shorter at the pillow ball inserts.

 

[JMS RC]

It will tend to happen going off abrupt jump faces and on harder uneven landings where one side is forced upward more than the rigs regular range of motion. Shock limiters might be a solution or possibly grinding the arms a tiny bit shorter at the pillow ball inserts.

Thanks. Apperently the TD diff cups are not solution, I thought they were longer.
I guess the solution for my Outcast will be, 4x6mm spacer on the shockshaft (stock on Talion V3) and droop screws set one turn lower. Grind off 2mm on the arms and use the original shims (removing the shims on the left arms seemed to help, the lower shim is about 1.5mm) moving the dog bone end 2mm closer to the diffcup.

 

[JMS RC]

Well I guess that plan somewhat failed, my front lower arms are bent ! possibly due to the axle slipping and was jammed against the cup when it landed !? Will be using the RPM arms instead, will not be grinding away those 2mm, will lose the shims instead. Now the lower steel shim is 1.5mm and the upper plastic horseshoe is 1.0mm, I guess I will try it first with that 0.5mm difference in camber. Don't know yet how exact the RPM arms measure against stock arms.

Both of them are bent downwards in the middle. The one to the right is how it should look like.

 

[RxMonkey]

Well I guess that plan somewhat failed, my front lower arms are bent ! possibly due to the axle slipping and was jammed against the cup when it landed !? Will be using the RPM arms instead, will not be grinding away those 2mm, will lose the shims instead. Now the lower steel shim is 1.5mm and the upper plastic horseshoe is 1.0mm, I guess I will try it first with that 0.5mm difference in camber. Don't know yet how exact the RPM arms measure against stock arms.

Both of them are bent downwards in the middle. The one to the right is how it should look like.

View attachment 20928

Wow that’s really something. I didn’t realize the arms could bend like that. I was wondering too, would it be possible to put thick o-rings inside the drive cup? Where the dog bone goes in. Seems like I’ve seen trucks with that (maybe I’m crazy). It’d take up some room and keep the dog bone from being able to float too far either way. If it keeps happening to me I may try it.

 

[WTF MIKE]

Well I guess that plan somewhat failed, my front lower arms are bent ! possibly due to the axle slipping and was jammed against the cup when it landed !? Will be using the RPM arms instead, will not be grinding away those 2mm, will lose the shims instead. Now the lower steel shim is 1.5mm and the upper plastic horseshoe is 1.0mm, I guess I will try it first with that 0.5mm difference in camber. Don't know yet how exact the RPM arms measure against stock arms.

Both of them are bent downwards in the middle. The one to the right is how it should look like.

View attachment 20928

Yeah my stock arms are bent also. Still have one stock one left. I replace them with rpm as they break

 

[JMS RC]

Wow that’s really something. I didn’t realize the arms could bend like that. I was wondering too, would it be possible to put thick o-rings inside the drive cup? Where the dog bone goes in. Seems like I’ve seen trucks with that (maybe I’m crazy). It’d take up some room and keep the dog bone from being able to float too far either way. If it keeps happening to me I may try it.

Didn't know they could bend like that either but I guess the force of the shock compressing as the sides are locked is a lot of force.
They do put o-rings in drive cup to limit the travel for the dogbone, you can kinda keep it in the middle. O-rings in the drive cups doesn't work on the front of the Talion though, there's only half a dogbone You could do this in rear though, although I don't think there's any need for it.

 

[Rich Duperbash]

It's normal for the arms to become bent upwards over time. All my stock arms become bowed. The Tekno arms become bent and twisted. I'm a fan of the RPM arms no doubt. They offer a tiny amount of flex that helps out the suspension and high speed handling over choppy uneven terrain. Some people have used fuel line in the dogbone/cup to help avoid displacement. This is a whatever works kind of deal.

 

[Rgcuban]

It's normal for the arms to become bent upwards over time. All my stock arms become bowed. The Tekno arms become bent and twisted. I'm a fan of the RPM arms no doubt. They offer a tiny amount of flex that helps out the suspension and high speed handling over choppy uneven terrain. Some people have used fuel line in the dogbone/cup to help avoid displacement. This is a whatever works kind of deal.

This just happen to my V3 Kraton that is only 4 weeks old. I’m going to try RPM arms if they don’t work and going with Aluminum front Lower arms

 

[RxMonkey]

So found my cause. A front lower A arm is cracked through. Time for RPM arms. Also the lower pillow ball was pulled out about 1/8” or so. I hate to see it cracked but it’s nice to have an explanation. You gotta pay to play.

 

[olds97_lss]

This just happen to my V3 Kraton that is only 4 weeks old. I’m going to try RPM arms if they don’t work and going with Aluminum front Lower arms

Curious if the current outcast AR106033 uses the same arms/axles/diffs as the Kraton. I think they all use the same stuff. I've only ran RPM arms on mine, was the first thing I did before I even ran it. I did shatter a rear RPM arm though, not really sure how. Only time I broke an RPM arm on any truck like that is when it was cold or when I hit something very hard at a high rate of speed.

I went back over my video footage and couldn't find the hit that caused this. Quite a few that should have hurt a front arm, but nothing hard on the rear that I'd think would break an RPM arm. It was a rear arm:

I've tumbled, cartwheeled 30 yards, hard one wheel landed my outcast a bunch of times already and haven't had an issue with the bone popping out yet.

 

[Snoprosledneck88]

Curious if the current outcast AR106033 uses the same arms/axles/diffs as the Kraton. I think they all use the same stuff. I've only ran RPM arms on mine, was the first thing I did before I even ran it. I did shatter a rear RPM arm though, not really sure how. Only time I broke an RPM arm on any truck like that is when it was cold or when I hit something very hard at a high rate of speed.

I went back over my video footage and couldn't find the hit that caused this. Quite a few that should have hurt a front arm, but nothing hard on the rear that I'd think would break an RPM arm. It was a rear arm:

I've tumbled, cartwheeled 30 yards, hard one wheel landed my outcast a bunch of times already and haven't had an issue with the bone popping out yet.

Ouch! Man you would think to break a RPM arm like that you would remember the hit! Heck I still have my stock rear arms installed. I have the RPMS in the parts box ready to go but so far so good. I guess you have the stock rear arm to get you by till you get some new RPM arms!

This has never been an issue for me either with the dog bone popping out except for the last couple times i took it out. Something is going on, just have found it yet. Planning on giving the rig some TLC tonight so maybe i will find it. A couple days ago mine came out under hard braking. I have no idea how it happened when I was jumping it steady for 20min before that and never had an issue. I will report back on my findings.

 

[olds97_lss]

Ouch! Man you would think to break a RPM arm like that you would remember the hit! Heck I still have my stock rear arms installed. I have the RPMS in the parts box ready to go but so far so good. I guess you have the stock rear arm to get you by till you get some new RPM arms!

This has never been an issue for me either with the dog bone popping out except for the last couple times i took it out. Something is going on, just have found it yet. Planning on giving the rig some TLC tonight so maybe i will find it. A couple days ago mine came out under hard braking. I have no idea how it happened when I was jumping it steady for 20min before that and never had an issue. I will report back on my findings.

I went and bought a replacement on my way home from breaking it. Nothing like running to the hobby store an hour away after you've been cooking outside in the 90F heat bashing your truck all day. lol!

Could be something cracked on you and you haven't found it yet, or maybe a blown wheel bearing/diff bearing allowing extra movement.

 

[Snoprosledneck88]

So I found one of my pillow balls was backed out a little bit. No cracks anywhere so I guess that mush have been it. Took it out for a quick run and didn’t have any issues.

 

[JMS RC]

View attachment 21070

So found my cause. A front lower A arm is cracked through. Time for RPM arms. Also the lower pillow ball was pulled out about 1/8” or so. I hate to see it cracked but it’s nice to have an explanation. You gotta pay to play.

So I found one of my pillow balls was backed out a little bit. No cracks anywhere so I guess that mush have been it. Took it out for a quick run and didn’t have any issues.

It may have been a very slight backed out pillow ball that caused my mishap. Anyway, the times that the axles slipped/popped, it happened when I was going up steep jumps, suspension fully compressed. Since it kinda wrecked the arms, drive cups and the dog bone ends I don't really want it to happen again. So RPM-arms, no shims, new drivecups, new dogbone pins and a stiff rubber cushions on the shock shafts. Took a bunch of really steep jumps last weekend and the axles stayed put.

 

[bicketybam]

I guess I am not the only one with this issue. I have a post about this over in the Kraton section. I removed all the shims and that seemed to take care of the problem. I was also running aftermarket arms and wheel hubs when this happened.