Kraton 8s diffs issue

[AleksandrRc]

Good afternoon, after a full service of my kraton 8s there are a couple of points. The first is the dangling differential cups, the second is the input gear in the bulkhead moves back and forth, along with the outer bearing. I don’t know if it’s worth leaving it this way, and what can be done to correct these backlashes?

 

[djrahbee]

Open it up! Haven't seen that before. Could be a stripped input gear, ring gear or maybe the bulkhead has cracked somewhere.

 

[AleksandrRc]

Open it up! Haven't seen that before. Could be a stripped input gear, ring gear or maybe the bulkhead has cracked somewhere.

No, all car was reassembled, new bulkhead, new internal gears in diff. All in ok condition, maybe it's a diff cup?

 

[djrahbee]

No, all car was reassembled, new bulkhead, new internal gears in diff. All in ok condition, maybe it's a diff cup?

Yeh I don't know man. First thing I would do is open it up and inspect. Just had to rebuild my diffs. I am in the process of converting over to aluminum diff cups, vitavon.
Also check the input gear..it shouldn't be sliding in and out like that.

 

[AleksandrRc]

Yeh I don't know man. First thing I would do is open it up and inspect. Just had to rebuild my diffs. I am in the process of converting over to aluminum diff cups, vitavon.
Also check the input gear..it shouldn't be sliding in and out like that.

The only option I see is that the diff bodies themselves are worn out where the outlet holes of the cups are. I also ordered an aluminum rcawd differential housing. Regarding input gear. Shouldn't it have any play back and forth at all? Because a person I know, after he removed this play, lost gear diff. And some other copies have the same move.

 

[Hector_Fisher]

Not likely a diff cup. In my experience, the wiggle is usually from a wallowed out diff case, meaning the tolerances on the fit of the diff outdrive through the diff case are slightly loose. Typically it's on the case side, not the spur side (as the spur is usually steel/metal). That doesn't necessarily mean anything bad. It might leak oil, or it might not. But as long as there is still oil in the diff, and there aren't excessive vibrations from the "loose" outdrive, i would feel fine to run it. If you already tore it down and didn't see any issues, i'd consider opening it back up in a half dozen packs just to make sure oil is still topped off and not leaking. (Though a tell tell sign of leaking is when your diff outdrives and driveshafts are greasy all the time).

Just my 2 cents.

 

[AleksandrRc]

Not likely a diff cup. In my experience, the wiggle is usually from a wallowed out diff case, meaning the tolerances on the fit of the diff outdrive through the diff case are slightly loose. Typically it's on the case side, not the spur side (as the spur is usually steel/metal). That doesn't necessarily mean anything bad. It might leak oil, or it might not. But as long as there is still oil in the diff, and there aren't excessive vibrations from the "loose" outdrive, i would feel fine to run it. If you already tore it down and didn't see any issues, i'd consider opening it back up in a half dozen packs just to make sure oil is still topped off and not leaking. (Though a tell tell sign of leaking is when your diff outdrives and driveshafts are greasy all the time).

Just my 2 cents.

Diff case is ok, i checked it.
Wiggle is on both sides of diff. Oil isn't leaking.
I think everything is intact, and this is natural wear and tear from friction. what about input gear? Do I need to install shims for a tight fit?

 

[Hector_Fisher]

Diff case is ok, i checked it.
Wiggle is on both sides of diff. Oil isn't leaking.
I think everything is intact, and this is natural wear and tear from friction. what about input gear? Do I need to install shims for a tight fit?

Outdrives and diff case sleeves wear down. Idk, i wouldn't be super worried about it. Again, as long as the diff has sufficient oil in it, and isn't binding on anything, then I wouldn't have any immediate concern. Most of my trucks have some sort of wiggle to the outdrives. Some smaller amounts, some larger amounts.

As far as shimming the input gear: Shimming this would increase contact area of the input gear teeth on the diff sun gear. But shimming this also changes what shims you should put on your sun gear, so make sure if you do re-shim you do both at the same time.

Do i think it's necessary to shim the input gear? No. The natural tendency of the spinning gears will be pushing themselves apart, so i wouldn't be worried about the movement. If you want that last little bit of gear contact, then shim it. But keep in mind that you can't shim too far otherwise you could potentially rub the input against the diff case. And i would leave at least a small gap for some "breathing room".

 

[RCbuzz]

What we cannot see in the video is what is moving.

1. If the entire bearing is moving, than the diff case holes are slightly stretched, even from the factory this has a little play.
2. Inside bearing race moving but not the outer (your bearing is wearing out).
3. Entire bearing not moving, then your output drive cup shaft or diff case sleeve is wearing down.

Keep in mind not all of these tolerances will be perfect so a little bit of play is going to happen.

As for the input gear, that is sadly normal on every 8S I have seen to date (including mine)... I would definitely shim that. It will snug up your differential mesh and extend the life of your diffs.

Check out this video:

 

[AleksandrRc]

Do I understand correctly that points 1,2,3 are about bulkhead and drive cup? I'm sorry, I don't know English very well.The outer bulkhead bearing moves entirely in its seat together with the input gear, and if we talk about the drive cup, then they move, and the bearing stands well

What we cannot see in the video is what is moving.

1. If the entire bearing is moving, than the diff case holes are slightly stretched, even from the factory this has a little play.
2. Inside bearing race moving but not the outer (your bearing is wearing out).
3. Entire bearing not moving, then your output drive cup shaft or diff case sleeve is wearing down.

Keep in mind not all of these tolerances will be perfect so a little bit of play is going to happen.

As for the input gear, that is sadly normal on every 8S I have seen to date (including mine)... I would definitely shim that. It will snug up your differential mesh and extend the life of your diffs.

Check out this video:

Do I understand correctly that points 1,2,3 are about bulkhead and drive cup? I'm sorry, I don't know English very well.The outer bulkhead bearing moves entirely in its seat together with the input gear, and if we talk about the drive cup, then they move, and the bearing stands well

 

[AleksandrRc]

What we cannot see in the video is what is moving.

1. If the entire bearing is moving, than the diff case holes are slightly stretched, even from the factory this has a little play.
2. Inside bearing race moving but not the outer (your bearing is wearing out).
3. Entire bearing not moving, then your output drive cup shaft or diff case sleeve is wearing down.

Keep in mind not all of these tolerances will be perfect so a little bit of play is going to happen.

As for the input gear, that is sadly normal on every 8S I have seen to date (including mine)... I would definitely shim that. It will snug up your differential mesh and extend the life of your diffs.

Check out this video:

But in input gear i should have a little bit play back and forth?

 

[Moirae]

Stop looking for problems and go drive and enjoy your rig. Thank me later!