Gear change on 3.0 Sport

[lightning]

Sometimes the gear change is notchy, and other times it is OK.
It does not crunch, but kind of crashes into the next gear (mainly from first to second gear) maybe as if you did not press the clutch down enough?
Other times it is fine.
I have read that these gearboxes are notchy. But why is it sometimes OK? The car has done 54,000 miles. I removed the CDV and changed the clutch fluid. The pedal engages a third of the way up.
I am wondering if the clutch could be
faulty.
But l had a Mazda MX5 that did this, and two new clutches failed to rectify it.

 

[t-tony]

Have you changed the gear oil recently? At 54k it's hardly run in.

 

[badman gee]

I changed my gearbox oil at 48000 and it makes a big difference.

It should hold 1.5 litres.

When you drain it there might only be a litre or so in there.

 

[GazHyde]

1st to 2nd on both the zeds I've owned have left a fair bit to be desired. Don't know how others find theirs.

I get my gearbox & diff oil changed at every service now. Doesn't add much to the cost, and it made a big difference the first time I did it.

Also added the Storm shorter heavier gear knob and that helps too.

 

[t-tony]

Heavier knobs. . . . .. here we go again.

 

[Mint]

mmm agree Tony, we haven't had a good knob thread for a few weeks

 

[oldcarman]

Heavier knobs. . . . .. here we go again.

And shorter also!!

 

[lightning]

I changed the gearbox oil last month, after a lengthy gearbox oil discussion on the other Z3 forum.
I ended up using Castrol 75w/90 which is their universal transmission fluid.
After being told this was no good for the Z3 transmission, l contacted Castrol, who said it was OK.
But they said l might be better with their 75w gearbox oil.
However the 75w/90 is still in at the moment.

 

[lightning]

The thing l find odd, is that sometimes the gearchange is perfect (from first to second) and other times it is obstructive.
It is totally random.

 

[GazHyde]

I ended up using Castrol 75w/90 which is their universal transmission fluid..

Just checked my last service invoice and my indy used EP80 gearbox oil.

The thing l find odd, is that sometimes the gearchange is perfect (from first to second) and other times it is obstructive.
It is totally random.

Yes, mine is like that too. But as both of mine have been like it, I've just given it up as a "feature" rightly or wrongly.

 

[lightning]

I don't want to start another "what gearbox oil" discussion!! As they go on and on lol

When l get a chance l'll replace the oil with the Castrol 75w. But l don't think it will make any difference.

 

[GazHyde]

Wasn't trying to start a debate just found the receipt the other day when unpacking . A rare thing for me as I normally lose receipts like that...

I didn't specify anything when I had it done, just asked them to change it. They could have put olive oil in it for all I know about automotive lubricants

 

[vintage42]

Why do people use hard-shifting gear oil when BMW specifies ATF of much lower viscosity?

 

[lightning]

BMW initially recommended ATF in the Z3 transmission, then changed the recommendation to gearbox oil SAE 75 or SAE 80

 

[vintage42]

Actually these are identical MTFs, manual transmission fluids, and not straight 75W or 80W gear oil.
http://www.ecstuning.com/BMW-Z3-2.8-M52_2.8L/Maintenance/Drivetrain/ES197386/
http://www.ecstuning.com/BMW-Z3-2.8-M52_2.8L/Maintenance/Drivetrain/ES1893847/
(BMW rebottles Pentosin MTF as its own.)

 

[lightning]

I am not sure there would be any advantage in using 75w/80 over a straight 75 or 80w

However, if that's what BMW are recommending, it will make people feel better if they use it.

Castrol technical told me the higher weight is better for hot climates and l "might notice the gearchange is a bit sticky" if l used their Universal 75w/90 in the UK in winter. They recommended l change to a 75w.

 

[vintage42]

I am not sure there would be any advantage in using 75w/80 over a straight 75 or 80w. However, if that's what BMW are recommending, it will make people feel better if they use it....

BMW are not recommending 75W-80 gear oil. Castrol's is a synthetic API GL-5 with a viscosity at 100°C of 15.0:
http://msdspds.castrol.com/bpglis/F...053593D/$File/Castrol_Syngear_75W_90_3750.pdf

That is twice as viscous as what BMW recommends, and the sulphurous extreme pressure additives in GL-5 gear oil will shorten the life of yellow metal synchronizers.

BMW recommend and sell a synthetic manual transmission fluid, Pentosin MTF 2, API GL-4 with no sulfur, with viscosity at 100°C of 7.7:
http://www.pentosin.net/specsheets/Pentosin_MTF-2.pdf

The proper viscosity should make shifts feel better.

 

[lightning]

Castrol technical said that their "Universal" transmission oil has been specially formulated and has no additives such as sulfur that will damage gearbox internals.

I specifically asked this question when l was on the phone to the guy.

But I'll change over to the BMW stuff if l can get it for a reasonable price in the UK. The dealer wanted £80 for two litres, l'm not paying that

 

[t-tony]

We recently changed the auto oil on a Z4 at work 7 ltr at £22.50 a ltr.plus lab. Glad I could do my own.

 

[lightning]

When l bought the Z3 l thought, let's change the trans oil. So l went to the auto spares storeand bought two litres of gear oil "hey, it's a car gearbox, let's put gearbox oil in it"
No, no, no l was told, your gearbox will fall to bits, your synchro hubs will become metal flakes attached to the magnetic drain plug, you will ruin the bearings, etc
So l went back and exchanged the gear oil for the Castrol product, which Castrol themselves say is OK. I put it in the transmission and it did shift better.
But no.....this is the wrong oil! It's too viscous, it's going to wear out my gearbox, changing will be "sticky"....what kind of alien transmission is installed under my gear stick, that cannot survive on automotive transmission oil, used in just about every other car on the road!! lol