Gearbox Oil Change - Temperature?

[jamieb]

Hi All,

I'm about to pick up my X5 and the first job on the list is to do the gearbox oil. It shifts really well (from the test drive), but my research has led me to believe its worth doing (car is at 110000).

So, I spoke to a handful of Indy's and had a few different quotes. Ranging from £450 and down to £230.
One of them have told me they'll need the car for the day as the fluid needs to be cold, whereas everything I've read says it should be at operating temperature.

Any thoughts on this? Should I even bother having it done?

Thanks

Jamie

[Smeeagain]

[quote="jamieb"]
Hi All,

I'm about to pick up my X5 and the first job on the list is to do the gearbox oil. It shifts really well (from the test drive), but my research has led me to believe its worth doing (car is at 110000).

So, I spoke to a handful of Indy's and had a few different quotes. Ranging from £450 and down to £230.
One of them have told me they'll need the car for the day as the fluid needs to be cold, whereas everything I've read says it should be at operating temperature.

Any thoughts on this? Should I even bother having it done?

Thanks

Jamie
[/quote]

Some will tell you that there is an increased risk of gearbox failure post il change, some say not. the rationale is that you flush out all the crap holding all the wear/tolerances together and then it lets go.
If I recall correctly BMW say it's sealed (it's not) for life. That means 60,000 miles in their book. Do you know much about the history - e.g. has the oil been changed before? If it's been done before then it may well be worth keeping the preventative maintenance going. if not then it may (or may not) be a bit of lottery. i know that sound a bit vague but it's not necessarily straightforward.

I can't comment on the operating temp for the oil change.

It's been well discussed before. Do a search then draw your own conclusions.........

[Smeeagain]

I just checked for you. Type "gearbox oil change" into the search function - there are five pages of posts for you to browse through ........

[jamieb]

It's reading all those threads that prompted me to look for a definitive answer! It's an absolute minefield!

Hmmmm... More thinking required!

[Steamyrotter]

Change when cold to avoid burns..
You can do warm but don't forget your hand is there undoing the drain plug.


Top up then run up to about 90degs.
Then re-check level and top up if necessary.

One important point.
ALWAYS undo the fill plug first before draining.
It is very annoying when you realise the box is now empty without any means of being able to re-fill!!!

Oh and whilst you do it get an OEM filter and change it.
The OEM should come with pan gasket and a new set of sump bolts.

Don't scrimp here as some aftermarket filters have disintegrated an then block the inlet starving the box of lubrication..
I didn't believe it until I took an EBay one apart after a couple of months and was shocked to say the least!!

[henrym3]

I changed mine at 110k, nothing in the full service history suggested it had been done before, now on 124k and if the box went belly up tomorrow I certainly wouldn't blame it on having done an oil and filter change. Got the stuff from BMW, expensive, yes but their original stuff lasted 110k, so can't complain. I'm in the "never known fresh oil and filter to do any harm brigade" I would however disagree with Steamyrotter about draining the oil cold. Having had occasion to drain cold oil prior to removing the sump the amount of crap that sticks to the side walls and parts needs to be seen. Heat it up and if you burn your hands think of the good job your doing getting all that crap out. You will increase your skills level by learning how to do it and not burn your hands :-[ Good luck with whatever you decide. 

[Steamyrotter]

We'll agree to disagree..

Gearbox 'oil' is actually thin hydraulic fluid anyway (as you know) so flows pretty well cold.

Either way you will need to drop the sump and clean any residue left there and on the magnet.

There are many documented failures after a change, but the chances are it was on its way out at that point anyway.  Changing the fluid removes the suspended friction material therefore being 'thinner' and cleans the passages.

Failures are usually due to excessive clearances in the valve body and pump leading to loss in pressure and then Mal operation of the gearbox leading to wear of the friction plates.
As these boxes do not have inbuilt pressure monitoring you will not know until it has probably gone too far.

Even in the rebuild and maintenance manuals it states that the pressure and actuating current (pump pressure setting signal) should be compared to ensure they correlate to a known range.
They say to fit a pressure gauge to the tapping point to do this.. but you try looking at that under the car when driving!!
You also need something to read the actuating current by the likes of INPA or equivalent!

I fitted a pressure transmitter and remote LCD display for mine as I was paranoid since having to remove it so many times!

[themoog]

Its utter rubbish that its 'sealed for life'. Any mechanical component that requires lubricant needs the said lubricant to be renewed at some point. What about engine oil?
Anyway, my trans was juddering and skipping so I drained it and refilled twice over two days to remove as much old fluid as possible. The old fluid was jet black but the magnets had only a mild fine paste on them. As for refilling I just ran it until it was pretty hot to touch the sump then I checked the level again. I also added a tube of Dr Tranny for good measure. I used Comma MVTF and ( I think) a Febi filter and gasket. New bolts?- what for- they only hold a pan on..
Its not a difficult job to do. Just a bit messy if youa re not careful. I didn't even jack the car up- I just drove all 4 wheels up onto a couple of paving slabs. Total cost was about £110.

[Steamyrotter]

New bolts..  why not?
They supply as part of the kit.
Don't know about anyone else but mine did have 2 bolts that I would not have reused mainly due to the crap heads on them rounding..

Just stating the benefit of my experiences to date..

At the end of the day you do your research, ask the questions and then make your own mind up..
Simple as.

If someone expresses an opinion from their research and experience then you either accept it or not.




Still what do I know???

[Greydog]

I am definitely in the maintain the gearbox group (Auto or Manual) and have had the trans fluid changed on both X5's I have owned.
"Why change the bolts" just like changing the fluid in a "sealed for life gearbox" as far as I am concerned it's just good engineering practice.

When a bolt is tightened it is stretched slightly, then as it heats up to operating temperature expansion puts a little more tension into the bolt. Re-using a bolt puts a pre-stretched item back in use that now gets stretched yet again and who knows if the last "mechanic" actually used a torque wrench and didn't just do them up gorilla tight.
It will always be a personal point of view but if bolts and gaskets are in the kit I use them.

[Smeeagain]

[quote="Greydog"]

"Why change the bolts" just like changing the fluid in a "sealed for life gearbox" as far as I am concerned it's just good engineering practice.

When a bolt is tightened it is stretched slightly, then as it heats up to operating temperature expansion puts a little more tension into the bolt. Re-using a bolt puts a pre-stretched item back in use that now gets stretched yet again and who knows if the last "mechanic" actually used a torque wrench and didn't just do them up gorilla tight.

[/quote]

couldn't agree more
Smee

[themoog]

There were no new bolts included in my kit so i took the decision to reuse the old ones. If they were supplied i would have.

[grumpywurzel]

Like it has been said a lot of failures that have occurred post oil change were bound to happen as I would say a lot of people change the oil once the box starts to misbehave. By then the damage is already done unless you are that lucky (suggest buying a lottery ticket at the same time!).

Whatever you decide do not skimp on the oil, make sure whoever is doing the work for you puts in the right stuff. Trying to remember the cost of the oil I paid when I had the box rebuilt, sure it was circa £120-150. I could of put some cheaper stuff in but then you are asking for trouble.

You said it shifts well, it should be almost silky smooth on gentle acceleration and barely noticeable when on full power. Make sure the box isn't suffering from the "lurch" when it drops into 1st at the lights, this could be a software update but I believe it led to the early death of my box,

These bolts.... how much torque are you guys applying to them? Yes they aren't stretch bolts for sure and if we were talking about head bolts then yes they should be changed but bolts to hold the oil pan on?

[jamieb]

This has provided yet more interesting reading. I'm definitely heading towards the "should be maintained" camp. I wont be doing it myself, i'll be getting an Indy to do it. The varying quotes is interesting though.. Likely to do with different fluids?

[henrym3]

Steamytrotter does fitting those bits that I presume you can monitor as you drive, give confidence, are the readings consistent, if they start to fluctuate does it give you a means of knowing what is going wrong. I assume you have the knowledge to interpret them.

Grumpywurzel, I was feeling confident that my box was in good nick till I read your comments. Up changes are as you said but I do get the "lurch" if I brake hard to a halt. Normal stopping is fine. Do I need to have it looked at or just wait till it goes and bite the bullet to get a rebuild/replace. From Thursday till Monday I have a 1500mile round trip, I'll try not to think about things to much.