[Czarke]

Hey all,

First post here, so forgive me if I leave out pertinent information. A couple months ago I bought a 2017 440xi gran coupe. Loving it so far. I installed a downpipe, intake, and stage 2. Then, a couple weeks ago, I changed the trans fluid for the first time at 72k. I used top tec 1800, as I thought I'd read enough positive reviews to warrant going with that over the lifeguard 8. I did the hot fill and everything, but it seemed like it took less than it should. It was slow to shift and laggy. I also noticed a squeaking when accelerating. I decided to get back under the car this past weekend and see if it would take any more fluid. I got about another 1/2 liter in but a good bit fell back out the fill hole afterwards.

Now, it is shifting significantly better, and it doesn't feel like the torque is being limited. However, the squeaking has gotten more pronounced. It does not seem to do this when cold, only after warming up.

I should note that the nut for the exhaust hanger on the mid-pipe has backed out as I struggled to get the fitment perfect when installing the downpipe. The squeaking could be coming from this, but I doubt it. Going to find a nut and re position the downpipe soon.

My question is, is it at all possible for this to be fluid related? I was thinking about redoing the trans fluid with OEM fluid, but wanted to get a second opinion before spending the money. Should I just take it to a shop now? Hoping I didn't manage to brick my transmission right off the bat, but that's what a safety fund is for I suppose.

Will be lessons learned regardless. Thanks for any help in advance. Will post audio for the squeaking after work today.

[Sammy17]

From factory I believe ZF Lifeguard is used. I would stick to using the OEM fluid during the change as mixing the ZF with another brand may cause issues, since you already put in top tec 1800, I would probably drain and refill that way the only thing in the trans is top tec and not a blend of both.

I also didn't see in your post if you changed the transmission pan as the filter is in the pan itself and during fluid changes its highly advised to change that as well.

[Czarke]

Originally Posted by Sammy17

From factory I believe ZF Lifeguard is used. I would stick to using the OEM fluid during the change as mixing the ZF with another brand may cause issues, since you already put in top tec 1800, I would probably drain and refill that way the only thing in the trans is top tec and not a blend of both.

I also didn't see in your post if you changed the transmission pan as the filter is in the pan itself and during fluid changes its highly advised to change that as well.

I did swap the filter. Wondering if I should do 2 changes with the ZF fluid a week apart.

[Sammy17]

Originally Posted by Czarke

I did swap the filter. Wondering if I should do 2 changes with the ZF fluid a week apart.

This would also work, only thing is more money in the end. I strongly agree with you and would also do a drain and fill with zf and then a filter swap and fill up with fresh zf fluid after a week or so.

[Czarke]

https://youtube.com/shorts/_HOL5pliLJw?feature=share

Video for context. Will see if I can get a better one tomorrow.

[Czarke]

Does anyone know what the part number or sizing is on the nut that goes on this exhaust hanger? Can’t find it anywhere. Pretty sure it’s a 13mm hex but I don’t know the thread.

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