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Auto trans cooler lines

46K views 27 replies 14 participants last post by  LuvZiah 
#1 ·
Has anyone done a replacement of these? Tischer and REM do not list the parts- I'm thinking big $$.
 
#2 ·
Not yet, but I always inspect them everytime I'm under the car.

Are yours leaking? Here are the part numbers according to the RealOEM TIS. On the Tischer site, #4 and #5 are listed at $72.06 and $90.33, respectively. They're not too expensive if you can DIY and make sure the transmission fluid level is correct after the repair. Although you might just need to replace the o-rings at the transmission connections, you'll need a tool like this to remove the old line and install the new lines at the autotranny cooler end (#1). You probably should change the ATF, filter, and pan gasket when you replace the ATF cooler lines if you haven't changed the ATF in the last 30,000 miles.
 
#3 ·
Yup, they're leaking, though I checked the fluid level when I discovered the staining on the lower engine bay cover, and the level is fine.
Good point re: the o-rings. I searched Pelican and they can get them, I guess I missed them at Tischer, I'll look again.
The OEM pic makes it seem that the lines are one continuous pipe or tube, but the leak is occurring where the metal tubing from the trans transitions to flex under the crank pulley.
This is a warm weather fix since it appears to be seepage.
AAnd the pricing is not as bad as I thought it would be.
Thanks for the reply.
 
#6 ·
Here are some tips:
  1. First of all look at the new hose and try to use "quick-connect coupling". In BMW TIS you can find the following image. Put some pressure on plastic gray socket (3) -> it will release blocking spring (2) inside coupling.
  2. Now start removing. Push return hose/line towards the front of the car. Use your fingers to press (3) to the back of the car as it's mentioned in the first step and release the hose to the back of the car. I know that it's not too much free space but it's possible.
The key point is to try and understand how the "quick-connect coupling" works.
 
#7 ·
Thanks for the reply. In my hurry to get my request posted I didn't make myself very clear. Both ends (cooler & trans) are disconnected. I need info on removing the two lines from the vehicle. Right now it looks like the driver side motor mount along with its support bracket are going to have to be removed.
The diagram you posted was spot on.
You don't even need a removal tool, however I did shoot P Blaster into each connector to flush out any crud.
The trans end requires dropping the front drive shaft, but that's necessary to fill/check fluid anyway.
Surprisingly little fluid loss BTW.
Thanks again.
 
#9 ·
I apologize for reviving an old thread, but this is for any future DIYers that may have questions on removing and installing a transmission oil cooler line and I think this thread contains valuable information.

It's not necessary to remove an engine mount, raise the engine, nor remove any other non-transmission related part other than the lower aluminum engine cover. You could do so to make it "easier" to get the line snaked out and in, but it may be more trouble than its worth.

You must be patient and have plenty of room beneath the car, then it all comes down to twisting, rotating, turning, pulling, and pushing (at both ends at times), following and guiding the bends and hose end of the line around various components; namely the steering column. You may have to apply only mild force once or twice to temporarily "bend" the hard line slightly in order to get it slip past a couple points, but nothing drastic. Certainly do NOT kink the hard line in any way.
 
#11 · (Edited by Moderator)
Remove bolt listed as item #10 in the realoem.com illustration. This secures the hold-down clamp that is permanently attached to the upper line while the lower line fits into its lower U-shaped channel. With the bolt removed, pull the two lines outboard to the left (driver's side) simultaneously.

On second thought, perhaps I may have pulled line out towards the rear. Heck, I'm so unsure at this point that you have to look at which end is shorter relative to the steering column. Pull the line out towards the longer end.
 
#15 · (Edited)
What I believe I used was a fine-toothed ratcheting boxed-end wrench. I have a Craftsman set, but I think there are some good brands found at your local auto parts store: you want a fine-tooth one that will ratchet even in tightly confined spaces such as that bolt.



And/or I could have come in from the opposite side that you have your wrench: from above, rear by removing the shift linkage to gain more room to get my hand up on that side.

Another technique I may have tried was to unbolt the transmission crossmember in order to drop the transmission (using a jack, of course) enough to give me extra room.
 
#16 ·
A squirrel chewed up the transmission cooler outlet. Is it difficult to replace? I purchased the outlet and inlet. I will do them myself. Is it difficult to remove the bolt that holds the inlet amd outlet tube? Also, there is this bulky thing blocking the bolt. How can I remove them?
 
#17 ·
I believe that "bulky thing" is the transmission shift linkage, which I think I disconnected to ensure I have as much room to access the bolt holding the clamping plate that secures both cooler lines to the tranny. If I recall correctly, I was able to remove the bolt without too much fuss, even in the tight spaces; might have to "feel" your way around the bolt as once you get your hands and tools up in there I think you're then working blind. With any R&R (remove and replace), having the right and sometimes esoteric set of tools makes the work so much easier (extensions, fine-toothed ratchets, universal joints, ratcheting box-end wrenches, etc).
 
#19 ·
Removed the inlet but can't seem to push the inlet cooler though. I will try again tomorrow bec its getting dark now.
Just be patient and work slowly. Whenever it binds on something, feel around the obstruction to determine how to orientate (rotate) the line and how much force may be necessary to gently persuade (slightly bend) the line around it.

Luckily I have the special tools to remove the lines.
I used these cheap plastic ones from O'Reilly that still were difficult to use. Next time I have to work on such special hydraulic fittings, I will pop for a higher quality "professional" set of disconnect tools.
 
#22 ·
I did this last night. Had the car on ramps, much more room to work around than on jack stands. On XI the drive shaft gets in the way, but here is what I did. To remove cooling lines attached to tranny I used a craftsman 13 mm box end wrench to get the bolt out. Don't forget to order two o-rings, because once you remove that 13 mm bolt both lines come out of tranny together. To get the bolt back in I used duck bill or needle nose pliers. Once in you should be able finger tighten it.

The best way to get access and maneuver the line was to remove the alternator and move the PS resevoir. This allows you to twist and turn the line better without bending it. I removed and installed inboard cooling line from the engine bay. I used a quick release tool to remove the inboard line from cooler and a foot down there is a plastic block holding the two rigid line in place to the chassis. I think it's a 10 mm bolt. That was a pain to get to but was much easier with alternator and the cooling duct out of the way. I think on the XI you need someone else on the other end of the line to maneuver it, because that driveshaft is in the way. Can't imagine what BMW would charge to do this job, but it took a total time of about 3 hours.
 
#23 ·
I just swapped ATF fluid and got nearly all the old ATF out by pulling the ATF cooler return line in addition to dropping the ATF pan, I'll post a DIY video soon. But I wound up with a leak at the quick-connect coupling. When inspecting the fitting, I felt grit/dirt operating the quick-connect. Tried some WD-40 as suggested to clean it out, and wrapped some Teflon tape in case the O-ring was failing. Just before I reinserted the line, I looked very closely at the mechanism, and noticed one of the plastic tabs had broken off and was sliding around, possibly blocking one of the metal tabs. Removing the broken tab + Teflon = no leak. Perhaps spraying WD-40 before removal will remove the grit/dirt around the quick-connect. I did use this tool to remove the hose as cleanly as possible, so I'd guess the grit/dirt caused the plastic tab to break.
 
#24 ·
I just got finished doing this job. The trick is to remove the steering coupler. It is the major road block in maneuvering this SOB. Once it is gone, the job all of a sudden becomes easy. I also undid the swaybar to give the line more room. My job also included tightening my OFHG bolts, so I removed the alternator. That may have given me extra space as well, I don't remember at this point. I also jacked up the engine to see if that would help, but honestly, I don't think it was necessary.
All future DIYers, do yourself a favor and avoid the nerve-rack I dealt with. REMOVE THE STEERING COUPLER TO GIVE YOU MORE SPACE TO MANEUVER THE LINE. I wish I had done this at the beginning. Now a 1-day project has turned into a 3-day nightmare lol. Good luck all.
 
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