Yes IMO what the others said, get tranny work sooner than later. I too have heard the same about metal pan in terms of fluid capacity difference. Hope it is as similar as abran says.

 

Alright, so a little over a month and 600 miles later, I checked under the truck this morning and the front cross member is wet. It was never this bad before. I've stopped driving it (didn't really notice anything up with the transmission). The mechanic who did the flush is taking a look today. I've ordered a metal pan kit just in case.

 

With regards to my reply above: I brought the question of the metal pan up with a good friend who happens to own a little LR garage in Switzerland. He is familiar with the fluid loss question but says it is negligible and worth the loss compared to user serviceability.

Coming from a guy that spent the last 30 years building defenders for african use, and his garage managed all the CT swiss selections... He said the metal pans were a great idea.

Considering how much the trans service cost me a few months ago, I will definitely be getting the metal pan next time around.

 

Ok so here's the big question. Is the pan swap doable DIY? Everything I read says it should be fairly easy to unbolt the old pan, saw off filter pipe, remove pan, drain fluid, replace sealing sleeve (probably the source of my leak), install new pan, and refill?

I also saw that the level checking procedure on the metal pan is different: you're supposed to check the level through the fill plug on the pan instead of the transmission.

 

We have done several metal pan swaps, the difference in fluid is negligible, there have been no reported symptoms as a result.

I get my pans from BMW, as the metal pan is factory on the X5.

 

Fill and level check is on trans body, not pan regardless of plastic or metal pan.

 

I suppose that makes perfect sense. Even though the capacity is less, you still want the same level oil.

 

I got a chance to put the truck on ramps and take off the heat shield to look around. To me, it really doesn't look like the leak is coming from the sealing sleeve. It looks like it is coming from the drain port on the plastic pan. I tried tightening the drain port and it turned about 1/2 a turn but given it is plastic I didn't want to push it any more. I wasn't sure if the torque specs on it were 8nm or .8nm...

https://imgur.com/a/b0Eei

 

I found the source of confusion about where to check fluid level with a steel pan:

BMW 6HP26x Transmission fluid level procedures with Steel Oil Pan: Genuine ZF Parts

On BMW's with this transmission, you need to remove a drive shaft to get to the fill plug on the side. The steel pans have a second fill plug in the bottom of the pan so you don't need to do that anymore. Should be the same fluid level regardless of where you check, one is just easier on BMWs.

 

I have installed those pans numerous times and wondered why there was 2 drain plugs. Strikes me as odd as the larger plugs port is only sitting approx .75" taller than the drain.

Maybe they use a special connection on their pump?