Jump to content
Sign in to follow this  
Blackman

E34 Gearbox & Diff Oils

Recommended Posts

Planning to change my gearbox and differential oils soon, as well as the power steering fluid, so just wanted to make sure that I've chosen the correct oil specs?

 

I've got an open 3.23 differential, so as far as I understand the correct oil for the diff should be SAE 75w-90? And the required amount is 1.7L? Probably something like Fuchs TITAN SINTOPOID SAE 75W-90 or Castrol Syntrax Long Life 75W-90?

 

For the steering, the cap on my PAS reservoir says "ATF", so I'm assuming pretty much any Dexron III ATF will be good? Stuff like Castrol Transmax Dex III Multivehicle or Motul DEXRON III? And the capacity is 1.2L?

 

And for the gearbox, I've got a manual 5 speed box, my car is a Sep 1992 build, so based on the research I've done, it seems like the oil is the same as for the power steering? Dexron III? 1.2L?

 

Let me know.

 

Thanks

Share this post


Link to post
Share on other sites
2 hours ago, Big Will said:

That should all be correct. You can also use 75w140 if you want for the rear diff.

 

I thought 75w140 was for diffs with LSD?

 

I've done a bit more digging and according to RealOEM, the gearbox on my car is S5D310Z, manufactured by ZF.  According to the ZF catalogue for manual transmissions, the oil used in these boxes should be BMW part number: 23007533513 or Castrol Syntrans B 75W

 

Source > https://aftermarket.zf.com/remotemedia/lol-lubricants/lol-en/lol-te-ml-11-en.pdf

 

Essentially, that's manual transmission oil (MTF-LT2) and it's 75W80, so quite a bit different from ATF?

 

I would be more inclined to use whatever the part manufacturer suggests, so will probably go for Castrol Syntrans B 75W for the gearbox.

 

The diff is pretty straightforward as all the sources that I've checked say 75W90 for the open diff, so that's easy. And the same for the steering, if it says ATF on the cap, then Dexron III is fine.

 

The gearbox can be quite tricky, especially if you are trying to go by the "oil selectors" on the oil manufacturer's website catalogues, but probably the best way to do it is to find out exactly what gearbox is on your car and then use ZF's or whatever part manufacturer's website to find the specific oil that should be used.

Share this post


Link to post
Share on other sites

Your gearbox should have a tag on it saying ATF. I believe the BMW fill was ATF Dex II but most use Dex III now.

 

S5D310Z is the same gearbox used on a lot of e34 and e36 cars. Your owners manual should note the type of fluid. It says ATF in mine.

The 75W140 can be used in both the open and limited slip diffs. The LSDs should have a gear oil with a hypoid additive. It doesn't hurt to use this on open diffs it just isn't necessary. Also, there are 75w140 fluids with a limited slip additive and others without...same for 75w90.

 

 

Edited by Big Will

Share this post


Link to post
Share on other sites
34 minutes ago, Big Will said:

Your gearbox should have a tag on it saying ATF. I believe the BMW fill was ATF Dex II but most use Dex III now.

 

S5D310Z is the same gearbox used on a lot of e34 and e36 cars. Your owners manual should note the type of fluid. It says ATF in mine.

The 75W140 can be used in both the open and limited slip diffs. The LSDs should have a gear oil with a hypoid additive. It doesn't hurt to use this on open diffs it just isn't necessary. Also, there are 75w140 fluids with a limited slip additive and others without...same for 75w90.

 

 

 

Had a look in the manual and it does say "ATF" there, but I'll also see if I can check the gearbox itself tomorrow and find out what's on it.

 

If it turns out that there's a label on the gearbox saying "ATF", then why is it that the gearbox manufacturer and the vehicle manufacturer recommend different oils? RealOEM has a choice of 2 labels that can go on this gearbox - one is MTF-LT2 and the other is ATF, giving an impression that either could be used?

Share this post


Link to post
Share on other sites

I haven't heard of this particular gearbox from ZF using MTF-LT2. RealOEM isn't always correct. Your owners manual should be ;)

 

If it helps, both Liqui Moly and Castrol recommend ATF for this application when you use their selector tools.

Share this post


Link to post
Share on other sites
2 hours ago, Big Will said:

I haven't heard of this particular gearbox from ZF using MTF-LT2. RealOEM isn't always correct. Your owners manual should be ;)

 

If it helps, both Liqui Moly and Castrol recommend ATF for this application when you use their selector tools.

 

I'm going by what ZF recommends for this gearbox in their "List of Lubricants" catalogue - see the link I've posted earlier above. The BMW part number mentioned in their recommended oils for this gearbox is 2300 7533 513, which is MTF-LT2. And they also recommend Castrol Syntrans B 75W, which is an equivalent to that.

 

As for oil selectors, it's quite strange how they list the E34 model types there. If you go for anything above 1992, they list the car as 525i, but the 525i-24V is only available to select for models between 88 to 91...

 

If you go by the year and choose 525i (1992-1995), then the recommended gearbox oil will be ATF. However, if you go by the engine and choose either of the 525i-24V options, then you get various MTF oils listed, including 75W90 and EP 80W? I checked a few oil selectors, including Fuchs and MOTUL - they are all the same.

 

I also read that BMW initially used 75W MTF oil in their gearboxes, which provides better lubrication because it's thicker, but then a lot of people complained on hard gear-shifting when cold, so in later production years BMW switched to ATF, which still does the job, although the gear shifts are always easier/smoother due to the oil being thinner compared to MTF.

 

 

Share this post


Link to post
Share on other sites

I read the links you provided before. I was just noting that most people go with the recommendation to use ATF as far as I know. I haven't read up on the exact specs of how MTF-LT2 compares with Dex II or Dex III ATF but it's certainly plausible that BMW made a decision based on cold shifts etc. That said, I don't think they'd recommend a fluid that risked damaging the gearbox as they wouldn't have wanted to be replacing lots of gearboxes under warranty at the time.

 

Total aside here but I've actually used the LT2 BMW fluid in my Volvo's gearbox simply because it was what I had at hand - identical specs to the Volvo equivalent fluid.

Share this post


Link to post
Share on other sites

To be honest, I doubt whether you put MTF or ATF in this particular gearbox, it won't make much difference anyway, apart from possible hard shifts when cold, which is probably over-exaggerated as a "problem".

 

I've already ordered Castrol Syntrans B 75W for the gearbox, along with 75W90 for the diff and ATF for the steering, so I'll update this thread once everything is done and report back on any differences...

Share this post


Link to post
Share on other sites

Also there's an interesting post from 2008 (still applicable today) on Bimmer Forums here > https://www.bimmerforums.com/forum/showthread.php?958283-atf-or-mtf

 

The discussion is about MTF vs ATF and further down you'll find an article by Mike Miller, tech editor from Roundel magazine in the US. A good read on this topic.

Share this post


Link to post
Share on other sites

That was a good read. Thanks for linking to it. I had used Redline products on my AWD Volvo wagon in the past. The MTL definitely made an improvement in the shifting for that gearbox but several of my seals began leaking. The MTL was a touch thinner than the stock fluid. I probably should have used the MT-90.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×