[gippy]

I've consumed as many videos as possible off youtube + read the ZF procedures + read what's on ISTA.
I have 2 remaining queries on the procedure:

1. Before getting to the gear running process, there is a preceding step which it says needs to be done first after filling with oil - but no one on youtube seems to do this step.

It's vague in when you're meant to apply it, because it suggests you should do it after filling with oil, but it then says also in brackets 'e.g. after a repair', suggesting that this step is done if yo'uve literally had a transmission repair and maybe the unit is dry of any oil to begin with.

I think our cars do have transmission coolers, in which case it says before following the shifting procedure, it says overfill then drive around?!

What is this step actually for and when should it be done? Is it required as part of the service, if so how?



2. The opinions on what gear procedure to follow are varied. The ZF process says "manually shift D1 and D2". I don't know what this means in the context of our units - if i shift to M1 with foot on the brake, then flick through to M8, it cycles back to M1 immediately - you can't hold it in any gear for 10 seconds as the procedure suggests.

So what is actually going on here - is cycling through M1 to M8 quickly enough to get the oil flowing through?

[AspektUSA]

Meyle has a great video on the ZF service, although I wouldn't use their ersatz parts.

They also mention you should replace the transmission electronics connector sleeve, as it tends to leak.

However, they also skip a step or two in the ZF documentation about holding revs at various points in the filling procedure.

[gippy]

Originally Posted by AspektUSA

Meyle has a great video on the ZF service, although I wouldn't use their ersatz parts.

They also mention you should replace the transmission electronics connector sleeve, as it tends to leak.

However, they also skip a step or two in the ZF documentation about holding revs at various points in the filling procedure.

thanks, that does give some answers.

- 'with the engine running shift through the entire range of gears' - the video shows him going through R/N/D, into manual (doesn't shift up through the gears), back to neutral and back to P.
I know you can pull away from standstill in M2, I don't think i've ever tried to in M3 - i guess there's no harm in flicking through anyway, it's unclear if the transmission does actually select through to 8th gear if you flick up to it quickly or not.

- He sort of does the procedure in reverse to the ZF document - as in, he's doing the gear procedure first, then an initial refill as the 'overfill', then goes for a drive to run it up to full temperature and advises to top-up again if needed.

So my conclusion is, that's the additional step i'll do - go for a drive after running through R/N/D and an initial overfill, run through all the gears with transmission run up to 75 degrees, then do a final top-up.

EDIT: people in the comments had a similar question and MEYLE responded:

[gippy]

Job complete.
The initial cold fill took 3 litres. After running up to temp and going through the gears it then took another 2 litres during the hot fill.
I did as per ZF, held D/R/M1/M2 for 10 seconds each, and cycled up quickly to 8 and back down - although i'm pretty sure no gears are cycled through from M2 to M8 and it's just a display function as it immediately drops back to M2 if you do that.

Took the car out for a drive, got it up to 75 deg, and did another hotfill after waiting hours for it to cool back down to 40 - put in another 0.5 litre and waited till the flow turned back to a drip and called it there as job complete. In total around 5.2 litres went back in the car.

if i can be bothered i'll do another hotfill and see if anymore goes in/until the fluid draining out is even lighter in colour. I don't think i overfilled quite as much as i should have before the drive to get to 75deg so maybe i'll run that process again.

The shifts are now silky smooth, especially from cold, i'm surprised how much of a difference it's made at 65k miles.
Very happy with the outcome and it's bizarre that this isn't part of the routine maintenance schedule.
All in all it was a really easy job to do - i made a set of wheel cribs which did cost £90 in materials (£60 wood, £20 screws, £8 drill bits for pilot holes) but i don't count that in the total cost as they will be used a lot more in the future. I copied this guy, and it was much easier and felt safer mounting the car onto these than onto 4 axle stands raised to their highest point.

the underfloor body protection did it's thing so nothing was even remotely corroded or seized in any way (8 year old car in UK).

I spent £180 on the ZF kit and £30 on a 3 litre pressure fluid pump which in hindsight wasn't necessary and i'll probably never use it again...
The cheapest quote i got to do the job from a ZF approved workshop was £474 incl. VAT, so i've saved myself £264.

[audi01]

Hi,
I am about to do this fluid replacement procedure and also was also concerned that all the YT videos on this subject did not mention the 0.5l overfill. Had a question about how you did the overfill, did you just pump another 0.5l and then plug the transmission quickly to minimise fluid loss? Did you do the overfill as per the ZF procedure (before going for a test drive)?

I'm thinking that there are allot of people out there who have replaced the fluid but are now at least 0.5l low on oil. Some people mention that the fill is around 4.5l so the 5.2l that you mention seem to confirm that the overfill is required.

[gippy]

Originally Posted by audi01

Hi,
I am about to do this fluid replacement procedure and also was also concerned that all the YT videos on this subject did not mention the 0.5l overfill. Had a question about how you did the overfill, did you just pump another 0.5l and then plug the transmission quickly to minimise fluid loss? Did you do the overfill as per the ZF procedure (before going for a test drive)?

I'm thinking that there are allot of people out there who have replaced the fluid but are now at least 0.5l low on oil. Some people mention that the fill is around 4.5l so the 5.2l that you mention seem to confirm that the overfill is required.

Yes as per the video. I kept on pumping in fluid for another 5 or so seconds even with it streaming out. Then plugged it up, went for a drive, warmed the transmission up to 75 deg, let it cool back down to 40, unplugged, no drips were coming out so put more in to top-up. That's the additional 200ml that went in to get to 5.2 litres.

I was going to repeat the procedure again whilst i do my engine oil service later this month, I'm curious to see if any more fluid can go in or whether it immediately starts gushing out and therefore i'll know its absolutely full.

[Polo08816]

You could always measure the amount of fluid you drain out - as a sanity check and another reference point. Of course the assumption is that the previous fill was correct, but at least it's a reference point.