Differential rebuild GQ RB30 4.375 Help!

Hi guys,
The diff has been whirring and growling for a while, when coasting, (not so much when accelerating)
This was the video of the problem posted on youtube while ago.

https://www.youtube.com/watch?v=ljzutTaygO4

I finally pulled out the rear diff centre.
To my surprise(or not so), I found the pinion nut was completely loose.
Pinion seal was obviously no good, because it was leaking diff oil a little bit(May be because of the loose pinion?)
I removed the drive shaft last year to clean it and grease it.
But, that couldn't have possible caused the pinion nut to go loose, can it?
So, was it the worn pinion bearing(s) that caused the nut to come loose(happened very quickly though)??!!

I'm wondering right now,

1)Are the outer and inner pinion bearings are stuffed? Or is this a problem caused by pinion nut coming loose
for some unknown reason?

2) Do I have to replace the pinion bearings? I haven't take them out yet.

3)How do you know the outer and inner pinion bearings are bad, without taking them out?
I can see the pinion bearings closely without taking the pinion gear out. But that apparently not possible
without pulling the bearings out?

4)So, do I need to pull the bearings out with a bearing puller and closely examine them first? Is it possible to do that without damaging the pinion bearings+races(probably a dumb question)?

5)Flange looks like there is a burred groove on it caused by the pinion seal(+loose flange, because the pinion nut was loose). Is that the case? See the picture.
Do I need to replace the flange or use some kind of speedy sleeve to repair it?

6)My point on asking all these questions is, whether it's possible to getaway with basically putting back things the way they were and only setting the pinion bearing preload without replacing bearings?
I'm not trying to be an el cheapo. But, prefer to not to fix it, if it ain't broken.


Crown wheel carrier bearings are looking good by the looks of it. I can't see any chips or visible wear/tear!
Crown wheel carrier bearings are not shimmed.

I can make the backlash adjustment with a dial gauge.
I don't have an inch pound torque wrench(not yet), but I can use a homemade one for the time being.
I can check/set the gear pattern with some acrylic paint or something as gear marking compound.
I can't find proper gear marking compound. Nobody sells them(??!!)

Thanks for any help/advice guys. It's much appreciated.

Wow! Not a single reply? Can I possible be that unpopular here??!!
At least tell me I'm crazy to attempt something like this instead of getting it done by a professional.
I won't have a choice now anyway. It's already out and in pieces & I got the parts & tools. I would have to go for it now slowly.
There is no information that I can see on this particular diff rebuilt by a backyard bloke.
So, I'm wanting to do it and post some pictures and videos for the benefit of other diff newbies like myself.
Come on guys! Somebody must have done this in the backyard, at least for fun and got it right.
I would appreciate a post by anybody, even a one saying I'm crazy.
I have the diff rebuild kit and tools handy. So, some diff savvy bloke out there tell me if I'm on the right path.
:first:

Sorry bloke, not my strong suit but I'd probably get to where your at with the same questions.

I reckon NissanNewby or Alitis007 would be your guys for these questions. They are the guys I'd ask. Maybe pm one of them and ask them if they could have a look at this thread. Newby is about tonight and might see it anyway.

Good luck mate.

Your on the right path.

Put the pinion in torque the nut and see if there is excessive play if there is replace it. You will find most of the specs for the diff in the manual on here.

Most auto shops or bearing suppliers should be able to help you out with the marking paint.

Quote:

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Originally Posted by nissannewby

Most auto shops or bearing suppliers should be able to help you out with the marking paint.

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Hi mate,
I tried both Burson & Bearing Wholesalers. They say they don't have it.
I'm guessing I end up with the wrong sales fella most of the time.
I'll try again tomorrow.
What do you think about acrylic paint(it's water based paint that comes in tubes for small jobs. It works
with thinner, petrol, etc as well)?!
Thanks

Quote:

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Originally Posted by nissannewby

Your on the right path.

Put the pinion in torque the nut and see if there is excessive play if there is replace it. You will find most of the specs for the diff in the manual on here.

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I put these two videos on youtube. Can you have a look at it mate?

https://www.youtube.com/watch?v=Vltv...ature=youtu.be
https://www.youtube.com/watch?v=3si_...ature=youtu.be
I haven't done what you told me to do above yet. I need to put the whole thing back together to be able to torque the pinion nut. I'm just about to do that.
Before, that I thought it might be a good idea to hear what you know about the bearing play as it shows in the videos.

Sorry to ask this silly question. I want the pinion gear out so I can have a good look at the pinion bearings. It's stuck as it shows on the video. I"m not 100% sure how to pull the outer pinion bearing without damaging the pinion gear. Should I use a three jaw puller? Or should I hit the pinion rod end with a drift or something? Or is there any other better backyard methods to do that?


Thanks

Well it is hard to comment on them without actually being there and also there is no preload on the bearings, as there normally is when assembled. In saying that if it was my diff I would replace the pinion bearing. The carrier bearings look ok. If you spin them in situ like in the videos how do they sound? If they are smooth as such they should be ok if they sound rattly, loose and notchy then they are probably cactus.

If you could get a jaw puller on there you could try it, I would just try a block of timber on the concrete then just drop it as such onto the shaft end using the weight of the housing to aid you. Don't drop from a great height just a nice height in which you can still be well in control. The easiest approach would be a press if you can access one.

Hi mate,
They(carrier bearings) look and sound ok. Spins fine on my assessment. No pitting or burr or score I'm happy to change them. It's that I don't wanna stuff up the pinion or the centre while trying to pull them out. Yeah, I know, I may sound ridiculously cautious. I'm pretty confident in installing bearings. It's that the part of taking them off that gives me a bit of a scare. That because it's obviously lot more delicate piece than wheel bearings. Pinion, ring gear, centre, etc on it's own are pretty expensive. I've never done a diff before, and I still wanna do it myself. :p
I don't have any jaw pulllers, but they're cheap to get. I have a kit like below as well,but I don't think it's any use for pinion, but good for carrier bearing pulling.
http://www.ebay.com.au/itm/380934910...84.m1436.l2649

Quote:

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Originally Posted by nissannewby

Well it is hard to comment on them without actually being there and also there is no preload on the bearings, as there normally is when assembled. In saying that if it was my diff I would replace the pinion bearing. The carrier bearings look ok. If you spin them in situ like in the videos how do they sound? If they are smooth as such they should be ok if they sound rattly, loose and notchy then they are probably cactus.

If you could get a jaw puller on there you could try it, I would just try a block of timber on the concrete then just drop it as such onto the shaft end using the weight of the housing to aid you. Don't drop from a great height just a nice height in which you can still be well in control. The easiest approach would be a press if you can access one.

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I hit the end of the pinion gear rod with a rubber mallet twice. There it goes.
Pinion dropped onto the timber bench. That was too easy!
Is this a good sign or bad sign???!!!

Now, I would like to put the old outer bearing back in and torque it?
Do, I simply torque the outer bearing into the pinion shaft with the pinion nut(with the flange in) or do I need to hit it?
I think, I would torque it.
Al these to find out the reason behind pinion nut coming loose.

I'm thinking hypothetically, is it possible for the pinion nut to come loose(nothing wrong with the inner or outer bearings of the pinion) because of the slightly wobbly drive shaft??!!

BTW, these are the videos I've just posted on youtube about the bearing play and races.

https://www.youtube.com/watch?v=eBPk...ature=youtu.be (this video is not that good)
https://www.youtube.com/watch?v=aMSt...ature=youtu.be
https://www.youtube.com/watch?v=MSPp...ature=youtu.be
https://www.youtube.com/watch?v=bnZH...ature=youtu.be
https://www.youtube.com/watch?v=iaU1...ature=youtu.be
https://www.youtube.com/watch?v=jYi8...ature=youtu.be

Hey guys,
Can I clean the diff centre unit(spider gear, clutch plate assembly) with degreaser and flush out any gunk?

Few more photos.
Soon after dismantling and cleaning the diff centre assembly off the diff centre housing.
It only took couple of not so hard hits with a rubber mallet(on the top rod end of the pinion gear) to get the pinion gear off the
pinion bearing.

These are some closeup pictures of the parts of the pinion gear, pinion bearings and races.

These three pictures show the carrier bearing preload adjusting shims & their locking retainer mechanism.
These pictures were taken before I removed the pinion gear off the diff centre housing. This is a late post of these pictures.

I've just went through it and this is a fairly good documentation of a dissection;-) In my opinion those bearings were no good. How did You end up with this project? Did You fix it or have You changed the whole thing?

Sorry, mate. Dom has been gone for a very long time, so don't expect an answer.