M52 2.5 diff/prop question

[bigwinn]

Hi all

First time under the new 2.5 N52 engined 07 plate E85

I'm trying to find pointers to the clunk I can hear when in lower gears when transitioning from power on/off. Also looking for evidence of what could be causing a whine from the rear.

Nothing immediate when I turned the wheels from either the hubs or the diff

However a few questions:

I cant see the diff drain plug- only the fill plug toward the rear of the diff. Where is this located?

See pic- I can see the prop input to the diff- should I be able to see a hole (looks like a missing bolt) in the mating/coupling area? Ringed on photo


Any other pointers I can look at in the first instance?

Cheers

Stuart

 

[markplant]

I don't think the newer cars had a diff drain, just a fill plug, you'd need one of those oil suction pumps,

 

[bigwinn]

Ah- makes sense

Thanks Mark will get the siphon out!

Stuart

 

[Mr Tidy]

I think there is a guibo somewhere - that may be causing the clunking.

Lack of a drain plug is why my 3.0Sis never had fresh diff oil. :lol:

 

[bigwinn]

Yeah I think I need it up on a ramp for a proper look

 

[Spriteracer]

The Guibo / flexdisk is at the other end of the prop at the connection to the gearbox. There is also a centering bush in the end of the prop where it picks up the crank. I changed both when I had the whole of the bottom of the car apart, but in fact at 80k+ miles they both seemed in good condition.

There is also the well known clank from the diff input flange casting knocking the diff. Lots on here about greasing it. I had the clank on torque reversals and greasing cured the problem. It felt fine when moved by hand before I took it off so I don't think you can put enough stress into it to test by hand. Easy to do if you have it apart. If you do, and teaching my grandmother I'm sure, but don't forget to mark the position and nr of turns of the nut holding the diff input flange so you can put it back on with the same preload.

 

[bigwinn]

The Guibo / flexdisk is at the other end of the prop at the connection to the gearbox. There is also a centering bush in the end of the prop where it picks up the crank. I changed both when I had the whole of the bottom of the car apart, but in fact at 80k+ miles they both seemed in good condition.

There is also the well known clank from the diff input flange casting knocking the diff. Lots on here about greasing it. I had the clank on torque reversals and greasing cured the problem. It felt fine when moved by hand before I took it off so I don't think you can put enough stress into it to test by hand. Easy to do if you have it apart. If you do, and teaching my grandmother I'm sure, but don't forget to mark the position and nr of turns of the nut holding the diff input flange so you can put it back on with the same preload.

Sage advice- thank you

 

[Zulu4]

Hi Stuart,
This short thread may be of interest to you:

https://z4-forum.com/forum/viewtopic.php?t=130036

 

[bigwinn]

Hi Stuart,
This short thread may be of interest to you:

https://z4-forum.com/forum/viewtopic.php?t=130036

Much appreciated- will keep fingers crossed its not the diff

Going to do a fluid change on it to see what comes out

 

[Spriteracer]

Hi Stuart,
I have just acquired a 3.0i auto diff as described in the quoted thread above. 95k miles and although not fitted yet, on inspection seems fine. Cost was £214 delivered so not the end of the world if you do have to change it. It has the advantage of a drain plug as well !

 

[bigwinn]

Hi Stuart,
I have just acquired a 3.0i auto diff as described in the quoted thread above. 95k miles and although not fitted yet, on inspection seems fine. Cost was £214 delivered so not the end of the world if you do have to change it. It has the advantage of a drain plug as well !

That’s not too bad at all- was it from a breaker?

 

[Spriteracer]

Yes it was - found on Ebay, "germanyautomoto2016" Quarry motors also had one but were more expensive.

 

[Spriteracer]

Just to add in case you haven't seen it yet, the diff input flange has 8 holes in it only 4 of which are used for the prop bolts. That could account for the "spare" hole you mention in your original post.

 

[bigwinn]

Just to add in case you haven't seen it yet, the diff input flange has 8 holes in it only 4 of which are used for the prop bolts. That could account for the "spare" hole you mention in your original post.

Much appreciated

On both counts!!

Going to get it on a ramp for a good poke around