Just did 4.8is transmission oil pan drop and filter.

[TiAgX5]

Originally Posted by JBF

Added pressure? The ZF document suggests there is an overflow outlet from which it would escape, that suggests it is not sealed ......

Yeah, the "sealed" statement is a common misconception.

The trans vents to the atmosphere thru a large tube.


This thread came to a halt when I brought it up...........

http://www.xoutpost.com/bmw-sav-foru...service-4.html

[Jungerishere]

Sorry, I don't recall exactly how the trans sits with car being leveled. Your statement below might be your problem? Yes, initial fill with engine off but must fill to level with engine running. And are you sure the squeal noise from 2-3 was your trans? Never heard of trans making squealing noise before. That sounds more like the transfer case making the noise.

Originally Posted by JBF

Added pressure? The ZF document suggests there is an overflow outlet from which it would escape, that suggests it is not sealed

You're probably correct, but I'm concerned that I wasn't able to get as much in to my transmission on the initial fill as people seem to report. I've seen many people saying the initial fill was 3.5lt but I got nothing like that in there - somewhere between 2-2.5lt (allowing for some still being in the pump). I can't see any logical reason for this considerable difference can you suggest one? I mean there are no variables relating to that. We're simply talking about initial filling of the oil pan up to the filler level, no engine running, no running through gears etc.

If you look at the transmission, with the car horizontal, it slopes down from front to back quite a bit - so much so that if you visualise where the oil filter intake sits and the level that the filled oil must be sitting at relative to that intake, it's quite possible that under acceleration or while going up-hill that intake isn't going to be sucking up any oil. That seems a bit worrying?

Did your E34 and Audi transmission sit parallel with the ground with the vehicle horizontally level or were they offset at an angle like the X5 is? In the ZF document it does show a diagram of the Audi version of this transmission but it shows it level which may or may not represent it's actual orientation.

As for checking the amount of oil fluid coming out, that would not have worked for me as I had a leaky sealing sleeve and gasket so suspect the level was low in the first place. What I do know is that with the transmission level (not the vehicle) I put in approx 5.5lt excluding overflow etc.

The oil change has solved my annoying squeal when changing up from 2nd to 3rd under moderate acceleration.

I'm going to do this again in the next week to cycle out more of the old fluid so want to make sure I do it right.

On the fluid temp, I kept INPA running when I went out for a test drive after completing the change. It seemed to settle around 85'C. I don't know if that's good or bad.

[lhordmclain]

FYI: For all thefollowers of this thread "Automatic Trans - They work well as long as you keep clean fluid and a clean filter in them. "

(Almost) Everything You Wanted to Know About Automatic Transmissions, But Were Afraid to Ask

[JBF]

I just had a phone call with the ZF transmission technical unit here in the UK. The chap I discussed it with was very helpful, he said to level it to the vehicle level not the transmission level, he said he's seen the Range Rover unit slopes down towards the transfer box too but the oil pan design should allow for that and his documentation for the X5 states vehicle level.

On the overfill topic, he stated that in an overfill scenario the oil may foam, at which point it will escape from the breather/overflow. The issue can be that when it foams and escapes from the breather it can then lead to a subsequent under-fill situation. He doesn't believe an overfill in itself will lead to excess pressure in the transmission or any type of seal damage.

TiAgX5 - I believe this large tube you describe ends up venting on the right hand side of the transmission, between the transmission and the transfer case, is that the one? I noticed it while under there and assumed it must be some kind of vent/overflow.

Jungerishere - I know you top it off with the engine running. If you look at GT1's original post he says:

12. Car took about 3.5 Liters. Started leaking out.
13. Started it up, ran through gears and killed it. Took out fill bolt again, put in about another 1L.

I may be misunderstanding the instructions although I'm sure I have seen others describe the same thing.

I'm going to do this again following the ZF instructions to the letter.

They say:

1. Bring transmission up to operating temp.
2. Idle speed.
3. Have vehicle horizontal, engage P and parking brake.
4. Drain old fluid.
5. Remove Oil Pan, replace filter, replace Oil Pan.
6. Fill with fluid.
7. Start engine, fill with more fluid. Replace fill plug and turn off engine.
8. Start engine, let run at idle speed, select R and D, hold each gear for 3 seconds. Engage P.
9. Check temp, when between 30-35 open fill screw, add more oil if it isn't running out.
10. At 40'C wait until oil stops flowing out and is only dripping. Close filler screw. Turn off engine.

I wasn't getting a squeal but a squeak upon gear change. I found the issue described in TIS and it said that it's due to degradation of the transmission fluid so to change it twice. Funny the dealership couldn't find that in TIS while I was complaining of this issue and the car was still under approved used warranty. They really are a$$holes.

[TiAgX5]

Not sure where it is located on yours.

On an M62 powered E53s, it's comes over the front/top of the left valve cover (removal of the plastic coilpack cover will expose the tube).

[JCL]

Originally Posted by TiAgX5

Yeah, the "sealed" statement is a common misconception.

The trans vents to the atmosphere thru a large tube.


This thread came to a halt when I brought it up...........

http://www.xoutpost.com/bmw-sav-foru...service-4.html

That is because it had devolved into a semantic discussion of what the word sealed means. It is vented to atmosphere, agreed. If you ford a river that is deep enough you could get water in it. I suppose. Not sure how water would be drawn in though, or if the electronics would still be functioning in water that deep.

In the thread you mention, you suggested that contaminants and so on could enter and degrade the trans fluid. You claimed the fluid became corrosive over time. That is similar in concept to engine sumps which get contaminated by by-products of combustion and fuel dilution. That ain't gonna happen. That is the reason it is referred to as sealed.

So, if you like, it is sealed from the contaminants which typically degrade other fluid compartments.

[JCL]

Originally Posted by JBF

On the overfill topic, he stated that in an overfill scenario the oil may foam, at which point it will escape from the breather/overflow. The issue can be that when it foams and escapes from the breather it can then lead to a subsequent under-fill situation. He doesn't believe an overfill in itself will lead to excess pressure in the transmission or any type of seal damage.

No issue with pressure, typically, but if the fluid foams it will not lubricate properly. Those air bubbles do not lubricate the same as the fluid does. Typical damage is related to that lack of lubrication.

[upallnight]

Originally Posted by JCL

That is because it had devolved into a semantic discussion of what the word sealed means. It is vented to atmosphere, agreed. If you ford a river that is deep enough you could get water in it. I suppose. Not sure how water would be drawn in though, or if the electronics would still be functioning in water that deep.

In the thread you mention, you suggested that contaminants and so on could enter and degrade the trans fluid. You claimed the fluid became corrosive over time. That is similar in concept to engine sumps which get contaminated by by-products of combustion and fuel dilution. That ain't gonna happen. That is the reason it is referred to as sealed.

So, if you like, it is sealed from the contaminants which typically degrade other fluid compartments.

It maybe sealed from outside contaminants, but what about the contaminants that are produce by the trans as it being operated? All manufacturers use filters and magnets to prevent some of the contaminates from circulating within the trans, but the ATF does get contaminated.

[JCL]

We may still be arguing semantics, but I don't think of the natural wear products within the transmission as contaminants. They are designed to be in there. The fluid doesn't get chemically changed, for example, like engine oil does. It certainly does get thicker due to clutch wear material, but fortunately the transmission adapts to that viscosity change, by design. It works fine until the filter is clogged and pressures drop. As we have seen, though, it can go hundreds of thousands of miles without that happening.

I would say the most common source of contamination is the fill plug, when owners introduce non-spec fluids.

[RRPhil]

The breather on a 5HP24 looks like this.



The breather tube that runs up & over the valve cover is for the front differential.

Could someone explain to me how you overfill a transmission that’s fitted with a combined filler/level plug?

Phil