anyone had success adding tranny oil through cooling line

[titan silber]

Pretty sure the only way you can properly check the oil level is with the engine running and after having put the car in gear. See https://www.zf.com/unitedkingdom/en_...hange_oil.html

[oldskewel]

Sure. I don't really understand why he was doing what he was trying to do.

But on my GM AT on my 3.0i (not a ZF, so many things are different), I can put in more ATF than would normally be there (if filled and leveled per spec) by simply jacking up the rear end of the truck, and even easier due to my sloping driveway.

The fill plug on the GM AT is at the rear, on the left side, so jacking up the rear means I can put more ATF in there than should be. I don't know where the fill plug is on the ZF AT's, but unless it is dead center (at the centroid) of the pan, jacking one way or another should enable this method.

I've done that trick, temporarily adding just a little extra, to simplify when it comes time to do the correct procedure.

The specified procedure (similar, I think for both ZF and GM, other than the mechanicals and fluid) requires a pretty low temperature - a range of 30-50*C, following having cycled the shift selector through all the PRND options, AC on, idling in Park, vehicle level. Then you're supposed to pump in enough new ATF until the fill hole overflows. With all that needs to be done, and the temp rising quickly, the low temp spec is tough to meet by the time the ATF level is actually set.

So after overfilling slightly the day before ... the next day, after things have cooled down, I can follow the correct procedure and temp is very quickly above 30*C, and I can just remove the already loosened filler plug to get the level set correctly. No time wasted fumbling with a pump or swearing.

[Attacking Mid]

oldskewel, that's exactly how I do it too. On my driveway slope, I can't quite get it to the ultimate full level, but I'm a lot closer than I would have been had I only filled it while level.

AM.

[BMTouring]

If you follow the procedure from ZF, you also fill the torque converter, that one is causing the differences in fluid you take out and put in.

To be more than sure, you can do the whole procedure more than once, no damage done. Going through the gears with the engine on pumps it all everywhere.



Just adding more to be sure is - in my humble opinion - completely pointless. ZF is not BMW, if the instructions where from BMW I would second guess them (and more often too) but ZF does not bs around with their products.

Having said that, the whole ZF procedure (in their workshops) includes replacing various parts in the 'switching block' / 'brain' of the gearbox and cleaning that out to the last nook and cranny. Adding more oil does not replace such an inclusive service.

[andrewwynn]

I would do the nose down fill to 'overfill' if the temp is above the low spec temp for filling, more trouble than worth to disconnect the hose when there is already a fill port. Just like @oldskewel says, next day get the transmission to fill temp and when level pull out the fill plug it will automatically drain to the correct level; i would use my scanner to read the temp of the transmission; the harness has a built in temp sensor.

[Crowz]

Yep either tilt the car forward or to the opposite side of the fill plug. Instant results and far less likely to mess something up doing it.

That said the fluid should never be above the level fill point. If you don't get what you want in there you probably didn't warm it up enough or didn't have the motor running when you topped it off. Either of which will cause it to not take the correct amount of the fluid.