99 528i Transmission acting up

[Bamsbmw]

Hi thanks for adding me to the forum! Lot’s of info on here and I will for sure find this useful.
I just purchased the 528i used now of course small issues but other wise love the car. I have searched the threads relating to the transmission trying to find something that relates to my issue. I have no codes it shifts fine no hesitations. What happens is after a hard turn or a hard braking then acceleration it seems to go into neutral and kick back in to gear. Now I checked the oil level and it was low so I added half a litre until the oil was running out the fill plug on the drivers side. From my experience over the years is this problem was low fluid but after topping it up I tested it and still happens the hesitation was reduced but not eliminated. I can assume the trans will need a rebuild the car has 210,000 km any tips on prolonging it or ideas if it might be a simple fix ? Thanks a bunch !

[amancuso]

Was the trans at operating temp? Also I believe you have to shift through the gears while filling. (2 person job)

[Bamsbmw]

Trans was not at operating temp like recommended. Very cold climate this time of year. I didn’t realize it had to be cycled through during top up. Thanks for the reply I will do this after I change the oil and filter it looked dark.

[amancuso]

No problem. This guide might help you, it says e36 3 series but your 4spd auto in the e39 is the same as the e36.

https://www.pelicanparts.com/BMW/tec...Fluid_Auto.htm

[djb2]

Don't be concerned about the transmission being _under_ the target temperature when filling. A slight over-fill is OK. (It would be really difficult to get a significant over-fill.) It's an under-fill that is a problem.

The typical error is that the engine is off when checking the level. The level must be set when the oil pump is spinning, keeping the internal chambers full. When the engine is shut off at least a quart of fluid immediately returns to the pan, perhaps significantly more with leaky seals.

Ideally you will have just shifted through the gears, but you aren't actually going to be able to shift past second gear in most cases.

[ross1]

Sounds like it is simply low on fluid. Could also be a clogged or loose filter. May as well change it since you are bothering to get under the car.
Filling these isn't rocket science. And the precision the official procedure specifies is ridiculous.
I use a 1/2" ID (pretty sure that's the size)vinyl tube which fits snugly into the fill hole. Run the tube up into the engine compartment and fill from there using a funnel. Fill to a static level at the fill hole.
Put the car in the air and run it through the gears, run it long enough to get things warm. Always good to drain it when warm so if you work fairly quickly this should be only a few moments. You can monitor the level in the clear tube. You WILL spill some when removing the tube, so what. A bit overfull is fine.
Be sure to also remove the front pan for the overdrive planetary gears and clean it out. That gasket needs to be ordered separately, it doesn't come with any filter "kit" I've ever bought.

[Chedley]

I agree. All that anal official procedure of going thru the gears at the right temperature is way over-rated.

I drain the old fluid, and fill -actually overfill- the pan with new fresh fluid, and you are good to go.

Transmissions are best overfilled than underfilled anyway...!!

[ross1]

Transmissions are best overfilled than underfilled anyway...!!

To a point an overfill does no harm but too much will foam the fluid and that is bad. When I put the plug in some fluid is still running out. It's worked that way for me for many years and one of my much maligned GM trannys is nudging up on a quarter million miles. Knock wood.

[geargrinder]

Sounds like it is simply low on fluid. Could also be a clogged or loose filter. May as well change it since you are bothering to get under the car.
Filling these isn't rocket science. And the precision the official procedure specifies is ridiculous.
I use a 1/2" ID (pretty sure that's the size)vinyl tube which fits snugly into the fill hole. Run the tube up into the engine compartment and fill from there using a funnel. Fill to a static level at the fill hole.
Put the car in the air and run it through the gears, run it long enough to get things warm. Always good to drain it when warm so if you work fairly quickly this should be only a few moments. You can monitor the level in the clear tube. You WILL spill some when removing the tube, so what. A bit overfull is fine.
Be sure to also remove the front pan for the overdrive planetary gears and clean it out. That gasket needs to be ordered separately, it doesn't come with any filter "kit" I've ever bought.

Yeah Ross I'd agreed but I'd just say that IS pretty much the factory procedure, you just know from experience, starting with a warm car, how much is "long enough" to get it in the right temp range.
Agreed the precision isn't super meticulous (just looked up the spec since it came up twice now in these 2 threads) which seems to be "between 30-40C" but really the thing thats important is <80C... so from experience I'm sure you get it in the zone more or less every time.

But the problem is guys don't use that process at all and either do the fluid w/ engine completely off, or, stone cold don't flick it into gear at all, or run it until its too hot, etc. I also agree too full is not great. If fuller was better then the factory spec would be "start the car when stone cold and top it off immediately with engine running, do not exceed 20C" or something...

[Bamsbmw]

Wow you guys are great it had been a few days since I checked the thread. Thanks for all the support I will keep you posted on how it all goes, Currently waiting on parts to arrive (trans filter kit) before I add new oil. It never occurred to me to take the other OD pan off and clean it but this makes sense. Now I’m going to have to find that pan gasket. Thanks again !

[jicaino]

I think a filter and fluid service would cure those symptoms. Mine was doing that too before and when I refreshed those items it was like a whole world of difference. Don't power flush!!! that's when things go wrong. Just drop the pan, let it bleed good and long, after it bled for over 2 hours you can briefly start the car in neutral and stop it without any further revving or going thru gears, then replace filter and gasket/pan and fill it up. ZF specs are fill lukewarm (around 30°C) and check at operating temp. If when you remove the fill plug at operating temp there's no fluid shooting out you're low on fluid. Add untill it starts to spill just to be safe on level, but then repeat the check after about 3/4 hours parked and top it up again. I don't know GM specs, we have pretty much all ZFHP19 6 cyl cars down here.