E85 automatic transmission query

[robertboeke]

A few weeks back I changed my automatic transmission fluid (E85 30i M54 5speed ZF transmission). It made shifting a little smoother and all seemed good. Then I noticed a very slight leak (a drip or two each day standing), knowing it might be another few weeks before I get round to redoing the gasket I thought I'd check/top up the oil.

As when filling I made sure it was as level as you can get it on axle stands, ran through the gears and left it running while I undid the fill plug... Oil absolutely gushed out so I quickly replaced the fill plug. Now I'm wondering if there's too much (because it gushed out)/not enough (because it's been leaking).

It'll be at least a week before I get time to swap the gasket etc. So are there any signs I should look for to signify whether there's too much/not enough oil in there?

Thanks in advance

 

[Matty_Z4]

Depending on how long you left it running for the oil could have gotten too hot and thats why it gushed out when you opened the fill plug. There is a procedure on filling the gearbox and part of it is that the oil must be at 50c and when it drips out the fill hole its at the right level. If the oil is too cold you will underfill and if its too hot you will overfill.

Im not sure you will notice any issues if its 500ml underfilled will probably be ok for a week or so. If the gearbox gets too low on oil you will start to ruin the clutch packs as they start to overheat and slip due to lack of oil. Not sure what a symptom of an overfill would be though.


https://z4-forum.com/forum/viewtopic.php?t=103330

 

[robertboeke]

Depending on how long you left it running for the oil could have gotten too hot and thats why it gushed out when you opened the fill plug. There is a procedure on filling the gearbox and part of it is that the oil must be at 50c and when it drips out the fill hole its at the right level. If the oil is too cold you will underfill and if its too hot you will overfill.

Im not sure you will notice any issues if its 500ml underfilled will probably be ok for a week or so. If the gearbox gets too low on oil you will start to ruin the clutch packs as they start to overheat and slip due to lack of oil. Not sure what a symptom of an overfill would be though.


https://z4-forum.com/forum/viewtopic.php?t=103330

Thanks Matty, that's eased my worries a bit. I'm probably not going to do many miles before I get round to the job anyway. I checked the temp when I initially filled and made sure it was between 40 and 50 c the whole time. I think it'd probably within a few hundred ml of what it should be, so I think I'll stop worrying about it. Thanks again.