I notice theres a bit of backlash when putting the transmission from park into gear, especially when it's cold and the rpm is slightly high, but at any rpm really.

Is this typical and can anything be done about it?
I assume it's the rear diff?

What about universal bolts? How many of those are there on the drivetrain? (I assume at least one, right?)

There are lots of places in the AWD and FWD Magnas where backlash grows as the car ages. Diffs and driveshafts would be main ones. How many Km on the car?
My front wheel drive TS has some slop in the diff, noticeable uptake when engaging drive.
Get under the car and check all drive components, unless there is noticeable wear in one of the rear drive components, just live with it. Costly exercise to set diffs up to as new backlash.
If you know someone else with an AWD, might be useful to compare the two.

Worthwhile checking the TPS adjustment.

There are lots of places in the AWD and FWD Magnas where backlash grows as the car ages. Diffs and driveshafts would be main ones. How many Km on the car?
My front wheel drive TS has some slop in the diff, noticeable uptake when engaging drive.
Get under the car and check all drive components, unless there is noticeable wear in one of the rear drive components, just live with it. Costly exercise to set diffs up to as new backlash.
If you know someone else with an AWD, might be useful to compare the two.

Worthwhile checking the TPS adjustment.
Heh, thanks MadMax- the cars got about 35k on the clock, 10k I've put on it since jan.
I don't expect there is much wear at all given the low k's, but I dk the history prior.

There is a bit of a thump and a metallic click or knock coming from the rear underneath when it engages. Sometimes it's pretty loud and I gotta wince when I hear it. Its repeatable when rocking between D and R, although oddly doesn't make a noise when rocking in and out of the same gear. My KH is very smooth and quiet in comparison, and thats got a couple hundred k's on it.
TPS - throttle position sensor?
I'd like to understand what causes backlash. I can imagine wear in the diff, but want to discount that for now given the low k's, unless someone knows of a scenario where it could deteriorate quickly with this behavior.
I did some research on the drivetrain yesterday and learned that they're often connected to the diff and transmission via universal joints. Couldn't those joints wear out pretty quickly if the dust boots are broken? (I imagine they're like CV joints, so packed with grease?)
How would the TPS affect it?

a thump and a metallic click definitely needs investigating. Get someone who knows what they are doing to lift it on a hoist and have a good look.

Is it difficult to get it out of park to put into gear? Or just when it goes into gear?

I'd be having the drivetrain components serviced. I'm pretty sure the trans, rear diff & transfer case are supposed to be serviced, (fluids changed) every 45,000kms, according to the log book. I don't know if it mentions a time, ie 36 months or not.

Your car may not have reached that km milestone yet, but it's still 7yrs old & I assume the fluids are too. How positive are you that the kms are genuine? They seem very low?

im commenting mainly to stay in the loop on this one, mine sounds like it might be a little similar, although its done it since i got it 3 years ago, and 80,000km ago. It doesn't happen every time, just occasionally....

Luke

The Kms are genuine and the car looks brand new, with no marks. When i picked it up it looked showroom condition, really stunning.
I have the service history, but basically serviced once a year. I've had the rear diff, TC, tranny, power steering oils all replaced. See my other thread about that. Brake fluid done. Timing belt, other belts, done. Has the original plugs in it. New tyres, alignment, balance.
I've had the underside inspected a few times with no problems found and one comment was "looks brand new!".

As I said in another post, I had the driver side and rear mounts replaced as well as the front lower control arm bushes. Waste of time and money, but I was trying to resolve harsh shift and had experience with my KH where the mounts were the cause and thought i'd give it a go, see my earlier thread on that. (Actually that introduced a vibration that I've got to get fixed next.)

But yeah, there is a bit of a thump when it first goes into gear and when going from D to R or back, especially when cold and RPM is up. Doesn't happen when driving, although it has some harshness in shift quality at any time, but the learning procedure I was given here reduced that to an acceptable level.

So I want understand all the components involved, but when I stuck my head under the car there are things that don't make sense to my untrained eye.

First up near the front of the car I can see a universal joint inline with the drive shaft. Looks like what I'd expect.

A bit further along though, near the middle of the car I notice another joint but this has some kind of round chamber in line with it, behind the joint.

Further along again I notice a different kind of joint. Seems to have two parts; a larger cylindrical chamber with concentric ringed pieces inline with it, bolted together. Then there is another of those round chamber like things behind that.

Would someone please educate me a bit, what are these things and what are they do?

Mine does it also. Always has. Not something worth worrying about. That online service manual spoke about it and apparently the fix is in the rear diff. Never bothered looking into it due to it not being an issue.

So I want understand all the components involved, but when I stuck my head under the car there are things that don't make sense to my untrained eye.

First up near the front of the car I can see a universal joint inline with the drive shaft. Looks like what I'd expect.

A bit further along though, near the middle of the car I notice another joint but this has some kind of round chamber in line with it, behind the joint.

Further along again I notice a different kind of joint. Seems to have two parts; a larger cylindrical chamber with concentric ringed pieces inline with it, bolted together. Then there is another of those round chamber like things behind that.

Would someone please educate me a bit, what are these things and what are they do?
Bump! Woukd someone please help me understand these...

Do you mean the tailshaft?

http://i1154.photobucket.com/albums/p540/munkeymanz/IMAG0873.jpg

Do you mean the tailshaft?
Yeah. That one looks different to mine though. The components I'm wondering about aren't on it. I'll try post some pics.

All awd tail shafts are the same. Andrews car is a TW

Must be the angle confusing me? Anyhow, here are my pics:

So this first one is a UV joint, and what I'm expecting to see...

http://i1159.photobucket.com/albums/p629/Kwawd/IMG_1566.jpg

Whats this next thing?

http://i1159.photobucket.com/albums/p629/Kwawd/IMG_1564.jpg

And this?

http://i1159.photobucket.com/albums/p629/Kwawd/IMG_1562.jpg
http://i1159.photobucket.com/albums/p629/Kwawd/IMG_1560.jpg

Whats that thing bolted onto the diff?

Whats that thing bolted onto the diff?

A big chunk of steel, which I believe is there to quieten an NVH issue with the diff.

That's a big chunk of rubber actually. It's supposed to dampen any diff vibrations/resonance so leave it on. And the tailshaft is rubber mounted to the chasis, just like the engine, gearbox and diffs. From what I can see, your AWD looks in good shape.

That's a big chunk of rubber actually. It's supposed to dampen any diff vibrations/resonance so leave it on. And the tailshaft is rubber mounted to the chasis, just like the engine, gearbox and diffs. From what I can see, your AWD looks in good shape.
Huh? Are u saying those things are chunks of rubber? The round things, and that larger cylindrical thing inline with the shaft? Do they have a name so I can stop calling them "things"?

Wow. Well I can imagine that there would be a fair bit of torque applied to that rubber, do they ever degrade?

That chunk of rubber on the diff is really interesting! That solution must work otherwise why do it, but where does the energy go? So the rubber vibrates in sympathy with the diff, absorbs some vibration energy by induction but then what? It must alter the resonance and disperse the energy as lower frequency sound I guess?
What if that chunk works loose?

Other questions in reference to my pics, what is that white stuff sprayed over the bolts and around them, looks like powder? What do u guys think about that rust, is it an issue?

None of the torque carrying components are rubber lol

None of the torque carrying components are rubber lol

No, but the bits that you can see that cover the bearings are!

If you want to give the various bits names, you could use the terms "universal joint", "Drive shaft support bearing" and "expansion coupling" - sounds a bit more upmarket to just calling them "things". lol

Most of the extra bits are there to support the drive shaft, or allow for expansion/contraction due to temperature changes. The large rubber lump on the diff itself changes the resonant frequency of the diff to outside it's normal working range - remove it and you will most likely get noise, vibration and harshness (NVH) at some road speeds. So leave it on, ok? Don't want the AWD to start acting like a Commodore! lol

[NOTE: Any mistakes in the above will be corrected by Mal, I'm sure!]

Hey, thanks MadMax (btw flipping awesome movie that).
I just noticed my owners book includes "lubricating the U-joint" as part of the service list of items they have in the front.
Would they be talking about these universal joints on the driveshaft? And how would we lube them?

I'm still wanting to know this: Other questions in reference to my pics, what is that white stuff sprayed over the bolts and around them, looks like powder? What do u guys think about that rust, is it an issue?

Really can not believe 3 pages of this.....
Attached is a few pages from the manual, the big bad plastic looking thing in the middle is a joint, similar to the inner drive shaft joint, are called a DOJ.

As for the white stuff, is most likely some crap off a road, underside of cars get sprayed in crap all the time, this is one of the cleanest AWD undersides out there so you have nothing to worry about

Your service book is generic, you will noticed many items that are for Tritons, Pajero's etc in there as well ie you do not get Diesel Magna's just for starters (although some do sound like a Diesel)

The rust, is surface rust, every car has it, put a small amount of sealant on it if you are really worried, I would not bother. DONT put anything on the drive shaft as it is balanced.

The Universal Joints are not servicable

That attachment explains it all really. Thanks Mal!

Really can not believe 3 pages of this.....
Attached is a few pages from the manual, the big bad plastic looking thing in the middle is a joint, similar to the inner drive shaft joint, are called a DOJ.

As for the white stuff, is most likely some crap off a road, underside of cars get sprayed in crap all the time, this is one of the cleanest AWD undersides out there so you have nothing to worry about

Your service book is generic, you will noticed many items that are for Tritons, Pajero's etc in there as well ie you do not get Diesel Magna's just for starters (although some do sound like a Diesel)

The rust, is surface rust, every car has it, put a small amount of sealant on it if you are really worried, I would not bother. DONT put anything on the drive shaft as it is balanced.

The Universal Joints are not servicable

Awesome, thankyou Mal! And thanks to all... I gotta say I enjoy learning about ths stuff.

Ok, I found a way to minimize the thump going into gear when cold: what I do is put it into R as usual, but only let it sit there for half a second so it doesnt actually engage the gear before moving it to N. Then when I move it back to R there is no big thump! It's like i've taken up the slack or something.
Seems to work, and it's quicker than waiting for the RPM to come down.

I think this would work when going into D cold too, just put it into D and then pull it out before it changes and you should be right to go.

Ok, I'm now ready to follow up on this. So to recap; there is a bit of a shunt when engaging from R to D or D to R.
Can be quite strong sometimes. Most obvious when engine is cold, but happens hot too. I think it's probably because the diff has a little slack in it which I'm told is not unusual for these AWD's, but it also has a metallic noise along with that sometimes that I'd like to get checked out. Could be anything really and probably needs a specialist to look at it to make sure there's no problem.

Can anyone recommend a place in the Melbourne area? They should probably specialize in AWD too, ideally. I have no clue who the big names are in this area. Or should I just go back to the Mits dealers on this?

Ok, I'm now ready to follow up on this. So to recap; there is a bit of a shunt when engaging from R to D or D to R.
Can be quite strong sometimes. Most obvious when engine is cold, but happens hot too. I think it's probably because the diff has a little slack in it which I'm told is not unusual for these AWD's, but it also has a metallic noise along with that sometimes that I'd like to get checked out. Could be anything really and probably needs a specialist to look at it to make sure there's no problem.

Can anyone recommend a place in the Melbourne area? They should probably specialize in AWD too, ideally. I have no clue who the big names are in this area. Or should I just go back to the Mits dealers on this?


Why not take it to Mal.

Why not take it to Mal.
I don't want to waste Mals time on a N&V issue. we'd have to progressively swap parts until we found anything wrong, would be slow, time consuming process.
I want to get a specialist to advise if there's any specialised diagnostics they could do to identify the cause using specialised equipment. I have no clue what they might have, but imagine they do this kind of thing all the time.
Need a place that can assess driveshafts, rear diffs for correct operation, I guess.

I think this has been fixed with the new engine mounts too! :)