[E92inAZ]

2007 328i 150,000 miles. 1 year ago I changed the fluid, replaced the filter, mechatronic seal adapter and the sealing sleeves because I thought it was a good idea. AFTER that, I started to notice the harsh downshift from 2 to 1 and a soft shift from 3 to 4. A few weeks ago I manually shifted from 3 to 1 and gunned it to avoid an idiot and now I'm getting a churning noise that is directly relative to engine speed. Sound like bearings going bad. I was at the dealership and they said it's coming from the transmission. It's really noticeable at idle but I have AA catless headers and gen 2 muffler so I can't tell if it fades at higher rpm or if I'm just drowning it out with exhaust noise. The nature of the noise doesn't change when shifted into drive or reverse from park so I'm calling it something on the input shaft. Looking at the assembly diagram I would assume it's pump related. There are a couple sets of needle bearings in the transmission but they're small and I don't think they'd make that much noise unless they were absolutely gone and then there would be more clunking. Of course, I've never gotten any error code throughout all of this, so no help from the car there. I had been preparing to re-replace the mechatronic adapter and seals anyway; and, since I'd be there, I was going to replace the shift solenoids too. My plan is to do that first and see if the noise persists before I pull the whole damned thing out, but I'm preparing myself for those easy fixes not to work. When I search for a new pump or means to rebuild the pump all I'm finding is eBay used or remanufactured parts which might be fine, but I don't want to risk the tranny and such an involved repair on maybe. Has anyone done this? Anyone know where I could get a pump if I need one? Do I need one?

[rjahl]

Originally Posted by E92inAZ

2007 328i 150,000 miles. 1 year ago I changed the fluid, replaced the filter, mechatronic seal adapter and the sealing sleeves because I thought it was a good idea. AFTER that, I started to notice the harsh downshift from 2 to 1 and a soft shift from 3 to 4. A few weeks ago I manually shifted from 3 to 1 and gunned it to avoid an idiot and now I'm getting a churning noise that is directly relative to engine speed. Sound like bearings going bad. I was at the dealership and they said it's coming from the transmission. It's really noticeable at idle but I have AA catless headers and gen 2 muffler so I can't tell if it fades at higher rpm or if I'm just drowning it out with exhaust noise. The nature of the noise doesn't change when shifted into drive or reverse from park so I'm calling it something on the input shaft. Looking at the assembly diagram I would assume it's pump related. There are a couple sets of needle bearings in the transmission but they're small and I don't think they'd make that much noise unless they were absolutely gone and then there would be more clunking. Of course, I've never gotten any error code throughout all of this, so no help from the car there. I had been preparing to re-replace the mechatronic adapter and seals anyway; and, since I'd be there, I was going to replace the shift solenoids too. My plan is to do that first and see if the noise persists before I pull the whole damned thing out, but I'm preparing myself for those easy fixes not to work. When I search for a new pump or means to rebuild the pump all I'm finding is eBay used or remanufactured parts which might be fine, but I don't want to risk the tranny and such an involved repair on maybe. Has anyone done this? Anyone know where I could get a pump if I need one? Do I need one?

Don' rule out the torque converter. The ZF unit is pretty tough but they can fail.

Once you rule out the stupid stuff like a broken bendix spring on your starter I'd be looking for a decent second hand transmission with TC.

[E92inAZ]

at this point I'm weighing the cost of replacing the pump and torque converter along with the solenoids as I had planned anyway VS. the pricing on used replacement transmissions.
Unfortunately, the only torque converters and pumps I'm finding are 'refurbished' and sold on ebay which makes my nervous because they're sold by people like the guy who is advertising his TC for a ZF6HP21 and GM6L45 as though that part could go in either transmission... (realoem lists them as different part numbers, so this makes me nervous)
I'm looking at listings for transmission oil pumps and they all seem to list the cast numbers for the pumps like this is important. how important is this? does a cast number have to match exactly for the part to be interchangeable?