Mystery M8000 winch driveshaft wear pattern

[Zorba]

For those who don't like to obsess over chickenshit details, you'd probably be better off hitting your "back" button now...

For the rest, bear with me for a moment while I lay this out, familiarity with the Warn M8000 would probably help...

Inset shows wear on the M8000 driveshaft, coincident with where it passed through the 3rd stage planetary via the "Splined Drive"...

Which would be this part right here - note witness marks from the 3rd stage planetary...

Other side of the same part. Note much sharper/less chamfering on this side, which was facing OUT.

Sun gears, old one on the right, which has an obvious problem.

Side view of same.

Old part on the now repainted drive shaft. Note how it cannot pass all the way through, even with part of the swaged on end missing...

An attempt to place the new part in the same relative orientation.

As it has no swaged end on it, the shaft is free to push 1/16" or so further in...

Here's what I think happened: The shaft, for whatever reason, was a BCH too long for the old Sun gear style, so it bowed, and wore on the axial opening of the "Splined Drive" as it (the driveshaft) spins much faster than the splined drive does. Perhaps incompatible revision levels between the shaft and the Sun gear. What with the new style Sun gear, it should relieve the tension and the shaft won't bow - says here.

IN ADDITION: I think the Splined Drive was in backwards, and the more chamfered opening should face outwards. After looking the entire assembly over, I see no reason why the more relieved opening needs to face inwards, yet it might make some sense for it to face outwards. And yes, this winch has "been into" before, no question.

Anyone with any thoughts about an alternate explanation and/or an opinion about the orientation of the Splined Drive part would be appreciated. Makes for interesting speculation if nothing else! I'll probably flip the drive shaft end for end while I'm at it.

 

[Blackjack]

You need to carefully inspect the bushing in the gear end cap. The sun gear should seat fully and have very little wiggle. It looks like the original was not fully seated in th bushing putting pressure on the planetaries that should not be there. That would explain marks on the drum coupler as it normally does not care what direction it is installed. You may need to look at the motor end and make sure that the armature shaft and brake coupler are seating together properly.

 

[Zorba]

You need to carefully inspect the bushing in the gear end cap. The sun gear should seat fully and have very little wiggle. It looks like the original was not fully seated in the bushing putting pressure on the planetaries that should not be there. That would explain marks on the drum coupler as it normally does not care what direction it is installed. You may need to look at the motor end and make sure that the armature shaft and brake coupler are seating together properly.

That makes some sense as well - perhaps the missing material from the end of the old Sun gear caused the compression situation. Good thought, and you're correct: The wear marks on the old Sun gear don't look right. And now that you mention it, the end of the bushing shows some odd wear marks - no picture at the moment. I couldn't account for the missing material off the old Sun gear - I ASS-U-MEd that it was either gone from a previous rebuild or it fell out or was blasted out by cleaner. Which in turn makes sense also - I'm thinking out loud as I type this. This whole thing may have been from a previous iteration, corrected "last time" but without the wonky Sun gear being changed out. Either way, I'll watch re-assembly carefully, the entire winch is still in bits. Motor has been gone through and is re-assembled, but the drum, brake assy, and entire gear box is still apart. Oh, and your observation regarding the "drum coupler" (your term, makes more sense than Warn's "Splined Drive") is duly noted as well.

Thank you for a fresh perspective! {BOW HERE}

 

[Blackjack]

That makes some sense as well - perhaps the missing material from the end of the old Sun gear caused the compression situation. Good thought, and you're correct: The wear marks on the old Sun gear don't look right. And now that you mention it, the end of the bushing shows some odd wear marks - no picture at the moment. I couldn't account for the missing material off the old Sun gear - I ASS-U-MEd that it was either gone from a previous rebuild or it fell out or was blasted out by cleaner. Which in turn makes sense also - I'm thinking out loud as I type this. This whole thing may have been from a previous iteration, corrected "last time" but without the wonky Sun gear being changed out. Either way, I'll watch re-assembly carefully, the entire winch is still in bits. Motor has been gone through and is re-assembled, but the drum, brake assy, and entire gear box is still apart. Oh, and your observation regarding the "drum coupler" (your term, makes more sense than Warn's "Splined Drive") is duly noted as well.

Thank you for a fresh perspective! {BOW HERE}

No problem. I would also suggest when you assemble the winch you do it vertically starting with the gearbox end and work up from there. This allows you to make sure that everything is stacking together properly as everything should just "fall" into place as you go. This also allows you to make sure the brake shaft is also the correct length as the motor will not be able to seat to the drum support if it is too long.