You shouldn't just compare viscosity. The fluid that you put in has to be similar in properties to what's already in there. That is more important than anything else. Pentosin fluid has similar characteristics to the factory Shell fluid. Either of these fluid will work. I have successfully used Mobil1 ATF in cars with ZF, but they were the 5HP design that came with Esso LT71141 fluid or Pensotin VW equivalent. I don't feel comfortable using anything but either Shell, ZF or Pentosin on the 5 though.
Regards.
Raj

 

What other properties would we need to compare? Color, chemical composition, additives...?

I agree with you Raj, but I am suspect of the marketing hype. Pensotin is made in Germany and is logically used on many european cars (Audi, VW, BMW, Jaguar, Range Rover, etc...). It does not surprise me that it is recommended by BMW and is also very expensive in the US due to its manufacturing origin. Castrol is made here by BP Lubricants and is designed to be integrated with many different types of transmissions, both German and Japanese.

So is it just marketing or is there a difference?

 

I wish I could answer you but the best place to research this would be BITOG. I know that ZF clearly states not to use anything that does not have some chemical composition. Anything slippier and it could cause problem. I decided to play it safe. I have been more open to take chances on cars whose transmissions cost less. Like I stated earlier, I have used Mobil1 ATF on BMW/Audi/VW 5 speed auto's with success. Just don't want to chance anything with the 5.
Sorry, I know that doesn't answer your question but I wanted to play it safe on this car.
Raj

 

Good timing on this thread. I have been noticing my transmission does not feel as smooth and I wanted to change it. I'm at 73k miles.

 

Does anybody have a DIY for this? Just curious, plan on doing this in the spring. Thanks for all the info fellaz.......

 

We'll be waiting anxiously!

 

DIY is all ready to go but the system would not allow me to post something with this many images. Darn!
I will get in touch admins.

Raj

 

OK, its up!
https://5series.net/forums/index.php?showtopic=88123

This is my 1st attempt here, so please provide feedback. i have done plenty of other forums but this is a new crowd .
Raj

 

itd be nice if someone collected some old fluid and did an oil analysis on it.

 

I do have the old fluid. Hmm, something to think about.
Raj