DIY: manual transmission and diff fluid change

[TheRuss]

Looking to get some fluids ordered up tonight. What is the benefit of using the LSD Castrol Diff fluid vs the open diff version of Castrol's diff fluid?

Is there and benefit? Could there be a down side? I.E. does it have friction modifiers for the LSD plates? Obviously increased friction would be bad in an open diff.

My oil supplier have e LsD version on sale at the moment, so it works out slightly cheaper than the open diff variety, but if the open diff fluid will work better then I'd be more than glad to pay the extra to ensure I have the correct fluid.

[JHZR2]

No reason not to get the LSD variant. The fm adds have actually been known to harden the surfaces.

I prefer amsoil svg myself. I'd consider going to a 75w-110 for a good lube.

[TheRuss]

Why do you prefer it? I don't think we get Amsoil in the UK though.

[JHZR2]

Amsoil is very consistent in terms of results. M1 is also very consistent in term's of results. Redline is not as consistent as Amsoil or Mobil but they can be quite good, don't get me wrong. I was not happy with redline in my e30 LSD or MT.

The major differences are base oils and additives. SG was reformukated in 2010 and uses a bit more stable base oil and more modern EP and AW additives. Severe Gear does contain FM's.

Severe Gear can be had in 75W-110, as well as 75W-90 and 140. It better matches the old school 80W-90 viscosity as the API cut the 90 viscosity to its lower half of the range, which is why for a spec, so many have gone to 140 lubes.

[TheRuss]

What would be the Mobil1 fluid for our cars? We can get that over here.

[JHZR2]

M1 sells a 75w-90 and 140 over here.

[TheRuss]

Just found this, it's what Castrol recommend for my car when iput my registration number in their website. Anybody have any experience of this or know if it should be any good?

http://www.opieoils.co.uk/p-69413-ca...gearboxes.aspx

Edit, I also notice that the open-diff Castroldiff fluid is more expensive (RRP) than the limited slip version. Wonder why that is? Perhaps something in it that isn't in the limited slip version?

[TheRuss]

OK, so I've been doing lots of research on manual transmission and diff fluids over the last few days. Fluids here cost a fortune compared to in the states. It'll cost me around GBP 100.00 just to change out the transmission and diff fluids (not including the cost of buying a pump to suck them out and refill them).

So, I firstly asked my oil supplier, who seems to be prettyknowledgable - they supply all different sorts of automotive oils and offer a "recommendation" service. Firstly I asked about using the Castrol LSD oil in my open diff - this is what they came back with:

There are no advantages to running the LSD version - it won't flow as well, so the diff is likley to get hotter and there is more drag. It won't protect any better. If you want the best for it, go for the Fuchs Syn 5, Millers CRX, Red Line 75w-90 GL5, Gulf Competition or Motul Gear 300.

The oils I mention above are ester based, making them the top level of oil quality available and will give the best protection.

So it seems that the Castrol stuff isn't quote as good as this lot, and that the LSD variant isn't any better than the open diff variant, but causes more drag - I'd suspected this all along, as I can't see BMW specifying an open diff variety of oil if the LSD version from the M cars works just as well. (Also, the LSD version is cheaper than the open diff version.)

Then I moved on to asking about the gearbox and was told:

You need an MTF for the gearbox and I would go with the Redline MTL, Amsoil MTF or Fuchs Sintofluid.

So I mentioned that an ATF was often recommended for these gearboxes and told him that cold weather shifting was a concern of mine, and the reply was:

Those gearboxes are specced to use a MTF (70w-80/75w-80) as standard, but there are often cold shift issues with them. What I recommend for the best mix of protection and cold shift ease is a mix of the Redline D4 ATF and the MTL in the gearbox. Put in the whole quart of MTL and make up the difference with the D4.

I then said that I was fairly sure that an ATF was factory fill on these gearboxes and he came back with:

If BMW specify MTF1 for the gearbox, that is basically an ATF and in approximately 2000, they started to recommend MTF2, which is a normal MTF grade. I'm 90%+ sure that the spec of yours would be MTF2, making the MTL ideal on paper, but while a MTF is the correct grade according to BMW, there are some cases where it can be too thick when cold and the ATF/MTF mix helps.

At this point I was thinking that a mix of D4 and MTF would be a good bet, but thought I'd check the Redline website and see what they recommended for my 2009 N54 6MT. The website showed the D6 ATF as the fluid for my car... so I decided to email Redline and find out what they really thought (never trust these online recommendations - they're probably filled in quickly by somebody that has to fill in recommendations for thousands of cars).

Dave at Redline emailed me back with the following:

Thank you for contacting Red Line Oil, in your 135i manual transmission the D6ATF is recommended as BMW is calling for the MTF-LT-3 fluid with the N54 engine, matching closely it’s viscosity and fluid characteristics.

An ATF is suitable for use in a modern manual transmission where components are specifically designed for it’s use.

D4ATF is popular in late model BMW transmissions where the MTF-LT-1 and 2 are called for matching the viscosity, some are also using the MTL with good results. The MTL being a higher viscosity could be stiffer shifting at lower temperatures with synchros designed for an ATF.

So I asked if it was OK/advisable to do a mix of D6 and MTL, and got this reply:

If your transmission is calling for the MTF-LT-3 fluid the D6ATF would be our recommendation.


The MTL being a higher viscosity would provide better potential protection and noise reduction, satisfying the 80W viscosity used in the earlier BMW transmissions.

Which doesn't relaly answer my question as to whether I should mix them.

At this point, I have no idea what to go for. I read the article my Mike Miller regarding fluids for the manual transmissions and he recommended MTL because it would offer better lubrication and protection, and he said that ATFs make very poor lubricants, which obviously isn't good for any bearings in the transmission. From that statement, I'd be inclined to use the MTL for its lubrication, though due to its thickness I don't know if it'd ruin the shifting of the car, especially in the cold.

I'm pretty sure at this point that the Redline 75W-90 fluid will go in my diff though, as that seems to be a bit of a no-brainer, but does anybody have any advice or anything to add that would help with my choice of transmission fluid? It seems that even the "pros" that know about this stuff can't agree, so I'm left utterly confused. Also, is my gearbox likely to be MTF1, 2, or 3? I presume 3, as per Redline's statement?

[Dackelone]

Originally Posted by TheRuss

....At this point, I have no idea what to go for.

Everything you posted above is true. I never heard of mixing ATF D4 and MTF. I would only use one or the other.

You might ask the guys on Bob the oil guy - forum. Here is an interesting thread...

http://www.bobistheoilguy.com/forums...Number=1643610

I'm pretty sure at this point that the Redline 75W-90 fluid will go in my diff though, as that seems to be a bit of a no-brainer, but does anybody have any advice or anything to add that would help with my choice of transmission fluid? It seems that even the "pros" that know about this stuff can't agree, so I'm left utterly confused. Also, is my gearbox likely to be MTF1, 2, or 3? I presume 3, as per Redline's statement?

Yes, for your diff fluid you could use: Redline 75W-90 GL5 gear oil. In fact I run this in my older BMW, an e39 535iA V8 with no issues.

You have to also realize that BMW specs two different fluids for the manual trans one for the N54 and one for the N55 powered cars.

What year is your car? Its a 135i right>>

BMW specs...
N54 manual trans MTF-LT-3 fluid. (trans holds slightly more than 2L)
N55 manual trans MTF-LT-5 fluid. (trans holds slightly LESS than 2L)


Two years ago when I first changed my N54 manual trans fluid... my German dealer over here looked up the fluid specs. They told me that MTF-LT-3 is specified, but that BMW now makes a MTF-LT-4 fluid. So that is what I ordered and used. The shift effort was better, but not great. About a year later I switched to Redline ATF-D4 and was very happy with the results.

I have been running the D4 fluid for almost two years now. I am getting ready to change it again. I will use D4 again with Redline 75W-90 GL5 in my diff.

Hope this helps you out in your decision.

Dackel


Other interesting threads...

use a pump like this to remove your old diff fluid.
http://www.1addicts.com/forums/showp...&postcount=113

What my old trans fluid looked like...
http://www.1addicts.com/forums/showp...2&postcount=91

My DIY for changing the trans and diff fluids...
http://www.1addicts.com/forums/showp...0&postcount=70

[TheRuss]

Thanks Dackel.

Why do you want to stick to the D4 then if Redline are recommending D6 and D6 closer matches the BMW fluid?

I've put a thread on BITOG already, and am being advised to use a different fluid again.

I think I'm more confused now than when I started!

[Dackelone]

Originally Posted by TheRuss

Thanks Dackel.

Why do you want to stick to the D4 then if Redline are recommending D6 and D6 closer matches the BMW fluid?

Well... I know that D4 works well in my car. And I know how I drive over here on the autobahn. Its normal for me to be in 6th gear 80 kph and go WOT all the way up to 290 kph (YES a real 290 kph!), without shifting. Don't get me wrong I do use the gears, but a lot of time your just in gear and you GO!!

I think its better to have a slightly thicker trans fluid than a thinner one(like the D6) in those situations. I think for US style driving this is a moot point. I really would not worry about using D4 over D6 unless you track your car or you park outside in the winter months. I have a garage here in DE.

I've put a thread on BITOG already, and am being advised to use a different fluid again.

I think I'm more confused now than when I started!

You know with oil types... its almost like a religion to some guys. You can ask one question and get conflicting answers and everyone will tell you THEY are correct. You basically have to switch on your BS filter and go with your gut.

I decided to run Redline ATF-D4 bc I had experience with using it in some older BMW's where MTF-LT-1 and LT-2 was spec'd. So I felt safe using D4 in my 135i.

So... IF your car is an N54 I would say run the Redline ATF-D4. IF you have an N55 I would buy the Pentosin MTF-LT-5 that the 1M uses.

CORRECT 1M Fluids List [Engine, Transmission, Differential
http://www.1addicts.com/forums/showthread.php?t=620282



I ran into a similar problem while researching which ATF fluid to use in my e39 535iA last year. The trans was slipping and acting up. I wanted to change the ATF pan filter and do a fluid change. I ran into so many threads saying NO don't change it IF you have high miles. Your trans will fail shirtly after changing it. Some said change it NOW. Then when trying to source the proper ATF fluid... THAT was a pain. So many choices and conflicting info. In the end I went with my gut and use Liqi Molly which met the ZF trans specs of "Esso LT 71141". When I found some Exxon/Mobil synthetic ATF over here that had this oil specs... I found out that quite a few e39 guys used that oil only to find out it really did not meet BMW & ZF's specs!! I was so confused. In the end I was either gonna spend $500 on 20L of ZF Lifeguard fluid from an official ZF dealer over here... or Buy some Liqi-Molly ATF(that also met this Esso LT spec) for $150. I ended up going with my gut and used the Liqi Molly ATF fluid. So far 40K kms and no problems with my e39. It even fixed all the trans slippage and jerky shifts. I was so happy!


Good Luck what ever fluid you use.
Dackel

[TheRuss]

Thanks Dackel, I'm gonna need luck - I've no idea what I'm doing at this stage!

[wolfe]

Originally Posted by TheRuss

Thanks Dackel.

Why do you want to stick to the D4 then if Redline are recommending D6 and D6 closer matches the BMW fluid?

I've put a thread on BITOG already, and am being advised to use a different fluid again.

I think I'm more confused now than when I started!

Out of curiosity, what are they advising you to use on BITOG?

[TheRuss]

Depends who replies to the thread... Everybody I ask says something different. Hence the dilemma.

[wolfe]

Exactly. I went through the same thing trying to pick engine and transmission oils. Frustratingly, it doesn't seem possible to get a 'right' or 'best' answer because, nobody has all the definitive data and answers.

I can't speak to any of this with any kind of chemistry or engineering background. However, based on the fluids I've tried in my car, I think that MTL or D4/MTL blend might be too thick for your car, especially in the UK climate.

for what it's worth, I've tried several transmission fluids now. My car is about due for it to be changed again and I'm still not sure what I'll put back in this time.

[Horigan]

I've found I get the best shifting performance with Amsoil Manual Syncromesh Manual Transmission fluid. I've tried MTL, D4, Royal Purple MT fluid, and find Amsoil to be the smoothest shifting in cold or warm temps. Most of my experience was with an E36 M3. I just changed the tranny fluid on my new to me 135i 6MT M Sport with Amsoil and immediately noted smoother shifting. Amsoil is a low viscosity (5W-30) oil, so I can't comment on autobaun applicability.

For the diff I've had no issues using Mobil1. Given this is an open diff, I'm going to change it out later since my mechanic has told me the BMW fluid is fine for longer intervals in an open diff.

Rich

[TheRuss]

Well a few folks on BITOG have recommended a Pentosin gear oil - as this is apparently what BMW use. Might be the safest bet - and would likely help the gearbox just by being a fresh fluid. People always think their new fluid shifted better than their old one, but most of the time that's probably more to do with it being new, clean fluid, than it being actually somehow better than the previous fluid.

[Dackelone]

Speaking of Pentosin gear oil... MTF-LT-5... here are some pdf's from my 1Addicts collection.



1M_trans_fluid_specs_MTF_LT5__TE-ML%2011_en0700.pdf

ATF fluid chart___TE-ML 11_en0700.pdf

Pentosin FFL-3_GB PDF_copy.pdf

Pentosin FFL-4_GB PDF_copy.pdf

[TheRuss]

So I guess Pentosin must make pretty decent fluids then? Is that what you first tried in your transmission Dackel?

[Dackelone]

Originally Posted by TheRuss

So I guess Pentosin must make pretty decent fluids then? Is that what you first tried in your transmission Dackel?

No. Pentosin is the makers of MTF-LT-5 fluid for use in the 1M and N55 135i's. When I first changed my trans fluid... latest BMW fluid was LT-4. But I suspect I could run LT-5 with no problems.

Since I am using Redline ATF-D4... I really had not thought of changing to LT-5. Maybe on my next trans fluid change.

I just wanted to post those pdf's to give you more data on trans oils. Here are some pics of what the Pentosin oil looks like. They also make it for Porsche. IF you look in the 1M thread on first service you can also see the info on this oil.

CORRECT 1M Fluids List [Engine, Transmission, Differential]
http://www.1addicts.com/forums/showthread.php?t=620282


Here is what the Pentosin oil looks like...

[TheRuss]

OK, so I finally gave in and decided to order the Pentosin, rather than the Redline. I thought I'd try to stick to stock, but just refresh it, as then I know I'm kaing an improvement (clean fluid) without any risk to the fluid not being designed for the gearbox. If I don't notice any particular improvement then the Pentosin has also made a good flusher in preparation for trying the Redline MTL, so either way I'm happy enough. I figure best to start with the fluid that's closer to OEM spec though, to avoid mixing the transmission fluids up too much. As the Pentosin is supposedly OEM fill, it doesn't get much closer than that!

One question I have is how much fluid does the transmission on the 135i take? All the DIYs I can find are either for 128is, or don't mention it exactly.

I ordered 4 litres and hope to be able to change the fluid twice in quick succession to get all the debris out. I'm thinking about 200 miles between flushes should do it.

However, if that's not enough then I need to add another litre to my order quickly! I'd rather not though, if 2 litres is enough?

Anybody got the exact spec?

[Dackelone]

Originally Posted by TheRuss

OK, so I finally gave in and decided to order the Pentosin, rather than the Redline. I thought I'd try to stick to stock, but just refresh it, as then I know I'm kaing an improvement (clean fluid) without any risk to the fluid not being designed for the gearbox. If I don't notice any particular improvement then the Pentosin has also made a good flusher in preparation for trying the Redline MTL, so either way I'm happy enough. I figure best to start with the fluid that's closer to OEM spec though, to avoid mixing the transmission fluids up too much. As the Pentosin is supposedly OEM fill, it doesn't get much closer than that!

One question I have is how much fluid does the transmission on the 135i take? All the DIYs I can find are either for 128is, or don't mention it exactly.

I ordered 4 litres and hope to be able to change the fluid twice in quick succession to get all the debris out. I'm thinking about 200 miles between flushes should do it.

However, if that's not enough then I need to add another litre to my order quickly! I'd rather not though, if 2 litres is enough?

Anybody got the exact spec?

Which engine do you have?


N54 6MT holds just OVER 2 Liters.

N55 6MT holds just UNDER 2 Liters.


WHEN you change your trans fluid, make sure you just drove the car(or an hour or so afterwards) and drain the fluid. FIRST remove the FILL plug incase you can not remove it - the last thing you want to do is drain all the fluid first and then realize you are stuck!

After all the fluid have drained from the trans... keep filling the FILL HOLE until fluid spills out - then close/put the fill plug hole back on the trans. The trans holds just under/over 2L's depending on which engine you have.


Dackel



PS: Won't you also change your diff fluid as well? The diff holds just over 1.2L's.