rear drive drive

[Darwin_R65]

Well after taking my bike for a longer than normal ride a few weeks ago (camping 100kms away and travelling at 140km/h as opposed to 20kms to work at 60-80km/h) I've developed a rumble in the rear drive.
It only appears to be on deceleration. I pulled the rear drive off today and oil was everywhere it was meant to be which is always a good start, and yes you can feel it in the rear drive unit when you turn it by hand.
Bearings feel OK from what I can feel without load on them. But when I match the crown and pinion there is definitely a non-smooth feeling in one direction.
I've tried the video function on my mobile phone to show what I mean, two videos attached (hopefully)
How much endplay should I expect in the pinion? and could it just be the rolloer bearings have worn allowing the crown to mesh too far into the pinion, or are my hopes for something simple pretty much invain and I'd better start looking at how deep the bank account is?

I've rung up the local bike wreckers as they repair as well as wreck, and he told me the BMW man knocked off early, so I'll go in tomorrow, but just wanted to sound out some of you guys first.

[Darwin_R65]

decided the file was too big to store on this site so I've placed the video here
http://users.on.net/~snj13/BMW/MVI_4652.AVI

warning the file is 5.6MB in size.

Is the end play inthe pinion normal? You'll notice the crown is quiet when rotated in a clockwise direction but noisy in an anti clockwise direction.

[Ed Miller]

I was scared to take mine apart so took it to a shop, but that pinion looks really sloppy.  It almost looks like it's broken.  (I did rebuild the differential for my Napco axle for my old pickup.)  I've heard rumbles when the pinion nut becomes loose; was yours tight?

How do the teeth look on the pinion and ring gears?

[nhmaf]

I am not certain - I think that some play is normal, but my first impression is that the amount yours shows seems a bit excessive.
Without any oil in it to dampen vibrations, it will sound louder, but that does seem like it would cause a rumble sound on the bike.  
I wasn't able to see the teeth on the crown gear - do they show a wear pattern on one side, such as ridges?   If the teeth don't show abormal wear then  it may be that bearing.  Sand the calluses off your finger tips like a safe-cracker and try just turning the pinion gear in either direction without the crown gear in place.  Do this  @ both extremes of the end-play and see if you can feel any "notchiness" or bumps as it turns one way or the other.

Did you also check your wheel bearings?

[Darwin_R65]

Teeth on the crown look fine, on the pinion there is an edge of the tooth that has a darker mark as though it has never engaged in its life.
thinking about this I applied pressure to the end of the pinion shaft and it rumbles in both directions now, so it would appear my problem is bearings. But seeing as it's a problem when pushed in, i suspect the roller bearing end.
Oh well I'm still taking it in for someone else as I don't the special tool for pulling this apart and hav decided not to try a screwdriver and hammer. I also am fairly short of spare time at the moment, and the kids and SWMBO want some attention.

[Darwin_R65]

well took the rear drive to the wreckers today and he said "yep that looks  like too much slop" asked how long and they said I should get a phone call early next week, 2 hours later i get a phone call, "come and get it, $45" apparently they reckon the internal nut holding the bearing in had come loose and just needed re- loctite -ing and tightening. half an hours labour. so I'm home tired, and just wondering whether I want to venture out at 9pm to start working on the beemer so I can ride tomorrow, or do I want to just go to bed.

[Ed Miller]

I would go to bed.  I do stupid things when I'm trying to rush through something and I'm tired.  

[Darwin_R65]

The kids made the decision for me, they should have been asleep ages ago, so I went in and spent time with them, (something all dads need to remember to do) and laid down in their room withthem until they went to sleep. Well after I woke at 10pm they were both asleep.

woke early this morning (6am is early for me) and put the bike back together deciding work could do without me for an extra hour, and it's a bike ride to work woohooo. I reckon this will have me in a good mood all day at work.