Manual transmission oil

[MJJamieson]

Quick one. GL4 or GL5?

Eurocarparts, Millers, OPIE and GSF all say GL5 but realoem part number comes up with GL4.

Help.

 

[csquire4]

Good thread. I went with Redline mix, good results.

http://www.z4-forum.com/forum/viewtopic.php?f=3&t=98273

 

[MJJamieson]

Ive read that GL5 can cause damage to Brass/Bronze parts inside the box, don’t know if there are any in the BMW box so want to be sure before filling with GL5.

 

[rally-chris]

Ive read that GL5 can cause damage to Brass/Bronze parts inside the box, don’t know if there are any in the BMW box so want to be sure before filling with GL5.

Correct. I don't know what material the synchroniser cones (or shift bushes) are made from, so it would be safer to stick to GL4 oils. The GL5 spec has more EP additives that cause the problem for brass/bronze, and they are only really a benefit in transaxles with bevel gears so not necessary in a BMW gearbox.

Chris
(20 years motorsport + niche automotive transmission designer!)

 

[bobo075]

I use Castrol Syntrans B 75W specialy made for BMW transmission and very pleased with it

 

[patriot66]

I use the Castrol Syntrans B 75W specialy made for BMW transmission and very pleased with it

+1

 

[Z4 - Kev]

This one.......


https://www.ebay.co.uk/itm/Castrol-Syntrans-B-75W-Fully-Syn-Gear-Oil-for-Manual-BMWs-3-Litres-3-x-1L-/172067021182?_trksid=p2385738.m2548.l4275


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[Newbers]

You need to have a look underneath the gearbox you can just see without jacking a coloured label. The colour (blue or green)
Denotes which oil. I found it very hard to find an oil that I was confident met BMW specs so I just bought from stealer. Wasn’t that dear and made a big difference to my e86 at 700000. Wish I’d done it years ago.