Knocking on acceleration and deceleration

PeteZ3

Zorg Legend
Supporter
Joined
Jun 18, 2015
Points
75
Model of Z
1998 Manual 2.8
@PeteZ3 one of the tech guys will be along shortly I am sure :thumbsup:
hopefully! I really cant find the answer on line, and I need to get to work tomorrow haha i dont think driving it without any oil in is a very good idea... lol
 

Redline

Zorg Expert (I)
British Zeds
Joined
Mar 10, 2015
Points
208
Location
Nuneaton
Model of Z
E89 20i msport
75W-90 gear/differential synthetic oil seems to be the general consensus. Some of that would be better than nothing even if you have to change it.
 

PeteZ3

Zorg Legend
Supporter
Joined
Jun 18, 2015
Points
75
Model of Z
1998 Manual 2.8
ok
75W-90 gear/differential synthetic oil seems to be the general consensus. Some of that would be better than nothing even if you have to change it.
ay, cheers, ill get that stuff then, unless anybody advises otherwise. thanks for the help! :)
 

andyglym

Shiny Dust Caps Make Your Zed Go Faster.
Supporter
British Zeds
Joined
Feb 20, 2015
Points
231
Location
Moresby, West Cumbria, England
Model of Z
2.8 Roadster

PeteZ3

Zorg Legend
Supporter
Joined
Jun 18, 2015
Points
75
Model of Z
1998 Manual 2.8
im just really eager to see if this knocking noise has gone or not! the suspense is killing me!
 

Redline

Zorg Expert (I)
British Zeds
Joined
Mar 10, 2015
Points
208
Location
Nuneaton
Model of Z
E89 20i msport
Need to check the BMW spec but i expect its API GL-5 oil needed. Seems to be lots of confusion over correct application for API GL-5 and API GL-4 oils. GL-5 is a higher performance oil targeted at applications where there's a high high sheer load (like you get in the Diff with the high speed movement and power delivery simply ripping the oil off the metal surface as the teeth separate). However, the uses are also down to the kind of metals used also.

I'd be surprised if its not a GL-5. Do check though.

See here for more details on drive train oil standards.
 

One Spanner Frank

Zorg Addict
Supporter
British Zeds
Joined
Aug 4, 2015
Points
61
Location
Carlton, Nottingham
Model of Z
2.8 auto
If it is a 'thing' with the 2.8, what sort of 2.8? Mine has a diff and a propshaft and half shafts, all of which wear and could give a clonk or knock on acceleration and deceleration, BUT it doesn't have a clutch. So if it applies to automatics too, it would rule out the clutch (possibly). It sounds to me like a drive shaft coupling. Does the Z3 have the old fashioned rubber wedge 'Cush drive'? They wear.
 

PeteZ3

Zorg Legend
Supporter
Joined
Jun 18, 2015
Points
75
Model of Z
1998 Manual 2.8
okay, so ive mannagd to get some of that oil, and ive put it in :) just taken for a test drive and it has improved the clunk a lot... however it is still there slightly in first and second gear ( it doesnt knock and clunk about when i engage the clutch even when im not being gentle. it just makes one quiet knock...., it is 100% diff related though. the thing i wanted too make sure of was that the diff bracket hadnt torn away and those welds were fine... all looks goood, I think its all bush related though. I need to explore and understand the diff more though. It looks like there is some slack on the output drive shafts that go to each individual wheel... but i dont really understand where exactly the slack is, wether it is in the diff or later on in the drive train... i believe it to be later on because when i turned the shafts individually i could feel it and there wasnt instant engagement of the diff... im not sure if this is normal or not though..... as i said im not well up on car mechanics so please excuse my lack of knowledge.

i may be wrong and it may just be another bush somewhere in that area... its a bit of a guessing game though as its such an old car and mine has very very little service history.

mines a manual and im pretty sure its not clutch related as the sound doesnt come from there.
 
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