DavidF

So, I have had to place a diaper under the bell housing of my '04 545i with ZF 6HP26 automatic transmission to catch all the leaking fluid. After about of year of that, I finally got enough of my projects done to start working on the problem. My assumption was a leaking input shaft seal. So, dropped the trans, pulled the torque converter and the seal seemed fine and still pliable. Hmm, maybe the oil pump to case or pump stator O-rings are leaking. So, just to be safe, pulled the pump and separated it. O-rings are not torn or hard, but who knows. Better safe than sorry and will reseal the entire front end.





I also took the opportunity to replace the engine main (crank) oil seal and replace the coolant crossover cover (it was definitely leaking). And, I will be replacing the transmission solenoids, bridge seal and transfer seals (tubes). The trans was working okay, but every once in awhile, it would slam hard when starting from a stop if I did not come to a complete stop. And, sometime kick while cruising at low speed. I feel this is all due to lazy solenoids...I hope anyway as the trans works fine otherwise. The fluid was black, but the inside of the trans looks like all others I have opened or rebuilt (rebuilt due to failed A-drum) with normal accumulation on magnets. Should be good to go. Costly repair, but will be worth it.


Incidentally, I was dreading dropping the trans on the 545 (V8), but it was easier than the E46 and the E38 that I have done before. Also, I discovered that some of the rigid insulation that covers the shift mechanism that penetrates the tunnel was hanging down and rubbing on the driveshaft. It wore the paint off the drive shaft and you can even feel a low spot in the driveshaft...been rubbing for a LONG time.


Almost forgot, I will be installing a Sonnax Zip Kit along with the new solenoids in the valve body.

KyleB

awesome. please keep this thread updated with plenty of pics and text, I love reading about this sort of thing and I'm sure others do too.

good luck with your project.

e6t.lab.rat

Subscribed!

txag_530i

I'm looking forward to following this post.

DavidF

Still waiting on parts, but went ahead and separated the valve body in case I needed to order a separator plate (I didn't, it did not delaminate upon removal). Here is another photo with Zip Kit box in background. Plan to work on it more this weekend, but still waiting on oil pan and solenoids...





Care should be taken when separating the valve body as there are several check balls, spring check valves, and screens that can fall out and be lost. All the check balls and valves are the same size and fairly obvious where they are located. Two of the check ball locations look like dog bones and it should be noted on which end of the dog bone to place the check ball.

DavidF

Project is finished and yes, I failed at taking photos as I was more interested in getting the project complete. Rebuilding of the valve body took more time than anticipated, so the project took all weekend. I filled the transmission with about 8 quarts of Motorcraft Mercon SP fluid (Sonnax zip kit instructions even mentions this fluid as it is the fluid Ford uses in the identical transmission assembled by Ford, under license from ZF).


Anyway, the transmission works fine, so far shifts fine. But, I have not put it through all the conditions where it would slam into first sometimes if I did not come to a complete stop before setting off again. And, time will tell if the leaks are fixed. But, so far so good.


If anyone needs any information on pointers on removing, resealing, and installing the transmission, let me know and I will be happy to pass along anything I know or learned.


Update: So far, transmission has not exhibited any of the faults/annoyances that were present prior to the valvebody rebuild. occasional slip/slamming from start is gone. Very occasional bucking/kicking at 2nd gear constant speed has not re-occurred. Torque converter slip is way down...meaning car has greater tendency to creep at idle. Before rebuild, slight incline would prevent car from moving forward if brake released. Now, more normal to other cars. I think I also notice less torque converter slip when pulling away. Only have a less 100 miles since rebuild, so TCM is still re-adapting so I expect the feel to get even better over time. But, otherwise, a huge improvement. I suspect most symptoms were due to fluid pressure loss at bridge and tube seals and less so a result of solenoid issues.