[Orion4]

Yesterday I changed the pan/filter and fluids on my 13 335i. Performed the necessary gear cycling process and brought the fluid up 104F-110F as listed on the side of the original pan/filter. Then Topped-off to the point of a very small steady stream out the fill hole. Installed the new plug. Went of a test drive and initially, through the neighborhood went fine, cycling through 1st to 4th. Then went for a longer drive on Melbourne's main streets. Encountered 2-3 instances of a hard shift from 1st to 2nd. Appeared to clear after more driving. Today it occurred 2 times during the day. Does not seem linked to anything in particular. Other than this issue, the trans is so much smoother-almost seamless.



Monday, I will jack her up and go through the post fill gear cycle again, bring up to temp and recheck fluid level. Anyone else experience this issue before?

[Polo08816]

Originally Posted by Orion4

Yesterday I changed the pan/filter and fluids on my 13 335i. Performed the necessary gear cycling process and brought the fluid up 104F-110F as listed on the side of the original pan/filter. Then Topped-off to the point of a very small steady stream out the fill hole. Installed the new plug. Went of a test drive and initially, through the neighborhood went fine, cycling through 1st to 4th. Then went for a longer drive on Melbourne's main streets. Encountered 2-3 instances of a hard shift from 1st to 2nd. Appeared to clear after more driving. Today it occurred 2 times during the day. Does not seem linked to anything in particular. Other than this issue, the trans is so much smoother-almost seamless.



Monday, I will jack her up and go through the post fill gear cycle again, bring up to temp and recheck fluid level. Anyone else experience this issue before?

Do you measure the amount of fluid you drain out?

[Orion4]

Not accurately. Had a bit of a spill. Although the top-off seemed bring the fluid up to the lip of the the fill hole, I will check tomorrow.

[Orion4]

A correction to the problem: It occurs when first engaging first gear and initiating aceleration. Seems to momentarily hesitate the engage with a delayed and bit of jerk. Again, only happening occasionally.

[Orion4]

Issue resolved. As i suspected as i reviewed the procedures, I did not correctly complete the 2nd fill/Top-off. Re-performed the post initial fill procedures this morning an the trans took an additional 1.8 liters. All buttoned up and road tested fine. Shifts much smoother than before I did the fluid and pan/filter. Lucky I did not damage it. A bit surprised I received no fault codes/alerts for low fluid, etc.

[frchdragon]

For information, what were the steps that you skipped the 1st time around?

[Orion4]

This is my first Auto Trans change and, by default, my first ZF trans fluid change. I've been a manual guy for 50 + years. The Bentley is seriously lacking in this area. I reviewed several DIYs including the FCP F30 328i fluid change.



What I did not see or recognize was the second fill must be done with the engine idling and in Park. Forgot all about the Torque Converter dumping all the fluid that was pumped into it during the post 1st Fill gear change procedure when the engine is turned off. Therefore, I was serious under-serviced. Also noted the FCP indicated a temp between 30-40C, while the OEM pan sticker read 40-50C



For "Bricks Like Me", I would modify the FCP write up to something like this:

1. Start engine
2. Put foot on brake
3. Shift transmission into "R" and "D" continuously
4. Shift transmission in manual mode from 1st to 3rd and hold gear for 3 seconds
5. Shift transmission in manual mode from 1st to 4th and hold gear for 10 seconds
6. Select all gears in manual mode from 1st to 8th and hold gear for 10 seconds
7. Keep engine speed at 2000 RPM's to ensure torque converter fills with fluid
8. Check temperature and verify that fluid temp is between 30°C and 40°C (Check the sticker on the removed pan for specific temps)
9. With engine idling and in Park, remove Fill plug and top off fluid until a thin stream begins to pour out. Re-secure Fill plug.

[Polo08816]

As a sanity check, I would measure the amount of fluid you drain. Obviously this works under the assumption that the previous fill volume was correct.

[Orion4]

Concur!

[thejeremyman9]

Originally Posted by Polo08816

As a sanity check, I would measure the amount of fluid you drain. Obviously this works under the assumption that the previous fill volume was correct.

How much is stuck in the pan/filter? I haven't done this, so not sure what is even looks like or what the capacity would be.

[Polo08816]

Originally Posted by thejeremyman9

How much is stuck in the pan/filter? I haven't done this, so not sure what is even looks like or what the capacity would be.

Based on my experience I would say 0.25 to 0.50 quart might be stuck in the pan/filter and other areas that might eventually come out with enough time.

If I'm in a rush on this job, I'll usually try to put back about 0.50 quarts more than I measured coming out because you'll lose some fluid trying to get the fill plug back on.

You're way better off overfilling the transmission by a small amount than underfilling it.

[auburnf30x]

Out of curiousity, how long would you say this service takes to perform on average?

I have performed this service on many automatics, just not the ZF yet. I am wanting to tackle this one afternoon after work. Lately though, I have been seriously underestimating how long things take to actually do.

[Orion4]

Originally Posted by auburnf30x

Out of curiousity, how long would you say this service takes to perform on average?

I have performed this service on many automatics, just not the ZF yet. I am wanting to tackle this one afternoon after work. Lately though, I have been seriously underestimating how long things take to actually do.

I'm not a good example because of my error, but if you're working under jack stands as I was , I would a lot 3-4 hrs. Now that I've done and learned a bit, 2.5-3 the next time

[auburnf30x]

Originally Posted by Orion4

I'm not a good example because of my error, but if you're working under jack stands as I was , I would a lot 3-4 hrs. Now that I've done and learned a bit, 2.5-3 the next time

Thanks! Sounds better for a weekend project.

[Orion4]

Originally Posted by auburnf30x

Thanks! Sounds better for a weekend project.

For me- definitely. By the time you get on stands and level, then later-off the stands and a test drive: that probably eats up 45-1 hrs. Add pre-setup and post clean up. The clock keeps ticking. Then if you have an issue like a seized fill plug, your time is gone. Plus you don't want to rush, especially, the 1st time.

[BashShah]

Originally Posted by auburnf30x

Out of curiousity, how long would you say this service takes to perform on average?

I have performed this service on many automatics, just not the ZF yet. I am wanting to tackle this one afternoon after work. Lately though, I have been seriously underestimating how long things take to actually do.

Under estimating is age bro....age....lol

[Polo08816]

Originally Posted by Orion4

I'm not a good example because of my error, but if you're working under jack stands as I was , I would a lot 3-4 hrs. Now that I've done and learned a bit, 2.5-3 the next time

So I think the real time consumer is waiting for the transmission to cool down. That's why shops like to save this job for the last job on the lift for the day. That way they can come in the next day and get the transmission into the required temperature range for bleeding.