Before you take your Grenadier's pan off, confirm the new aluminum pan has the 2nd transmission fluid uptake port. Most ZF pans have one large uptake port as part of the filter, Grenadier's use a ZF pan with a second, smaller uptake port similar or identical to the BMW G20/G21s (this pan's setup is for BMW "mild hybrids") if I recall correctly, also part of the filter. The attached picture shows a Grenadier's ZF pan with the second port at the top left. I'll post more when I have time and have better understanding about what the 2nd port does -- it's either there because we have the engine stop/start feature and this 2nd port is to help keep the ZF ready to go in those cases and/or some other reason(s). I haven't found a metal / aluminum ZF pan that has a filter with this 2nd port, and I'm not sure if I can grab the filter with the 2nd port and retrofit to an aluminum pan without the backing mount behind that 2nd port on the pan's floor. If anyone has done this, please post.
/s.
@scottg great catch here, thank you for posting and sharing this photo.
Interesting development. The pans that I got do not feature that aft pickup. That’s quite curious. The pans/filter’s that I received from FCP Euro are OE ZF and Genuine BMW but do not feature this second fluid pickup. Doesn’t seem like any aftermarket option has one either and I would steer clear of those anyhow. Nor do the 8-speed Jeep Wrangler steel pans.
I was just about to do this service within the hour and now I will refrain for further research & need to source a different OE pan with this fluid pickup configuration, otherwise there certainly could be a pressure variance that the transmission won’t like.
Let me grab those part numbers that may no longer be applicable and some photos of the pans, gaskets and filters.
Edit: Part Numbers for the two aluminum ZF/BMW (same supplier) pictured below:
*NOTE: ^these may not be compatible with the Grenadier's specific 8HP configuration
I think both you and
@Krabby are likely some version of correct: perhaps for start stop (although other models have had this for at least a decade) but certainly for high pitch and roll angles (off camber), it’s a bit odd I would expect there to be enough fluid in the sump given depth of the pan and fluid volume. Hard to know without reviewing any engineering data.
Re: mild hybrid setups: I wonder if the newest gen X3M 8HP would have this filter setup with an aluminum pan/deep fin design.
We likely need to start a separate thread for the topic of transmission fluid changes and pans.
@scottg do you happen to know the part number for your Grenny pan you pulled off?
