Front Transmission Seal Massive Leak

[eva89]

So I though the rear main seal was leaking on my car (03 525i, 5-Speed Auto), as there was a massive oil leak coming from between the engine and transmission, in the bell housing area. Then I went to pull the car out of the garage, and it wouldn't move. At all. Looks like it is a front transmission seal that failed, and leaked all the fluid on to my garage floor. Has anyone ever heard of this seal going bad before? Is it indicative of bigger transmission problems? The car has 155k miles, and has never had any transmission issues to date.

[rf900rkw]

The front seal on these never fails. We have no pattern failure to go from. You'll have to pull the unit and investigate whats going on.

[TechWrench]

So I though the rear main seal was leaking on my car (03 525i, 5-Speed Auto), as there was a massive oil leak coming from between the engine and transmission, in the bell housing area. Then I went to pull the car out of the garage, and it wouldn't move. At all. Looks like it is a front transmission seal that failed, and leaked all the fluid on to my garage floor. Has anyone ever heard of this seal going bad before? Is it indicative of bigger transmission problems? The car has 155k miles, and has never had any transmission issues to date.

Normally, a front transmission, or pump seal, starts to leak gradually and slowly gets worse. The only time I have seen a sudden, total failure of a front seal is if the support bushing in the front pump breaks loose, walks forward on the torque converter neck, and causes the seal to rupture. I have no actually experience with this happening in a BMW trans, but have seen it numerous times in other manufacturers units. In any case, removal of the trans, pulling the torque converter, and inspecting the front seal is necessary to make an accurate diagnosis.

[rf900rkw]

No pump bushing (it's a needle bearing) and the front seal is retained by a circlip. It is an unusual failure for sure, enough to have me thinking of other possibilities... like a cracked converter or some such. No matter, step one is to remove and inspect.

[TechWrench]

No pump bushing (it's a needle bearing) and the front seal is retained by a circlip. It is an unusual failure for sure, enough to have me thinking of other possibilities... like a cracked converter or some such. No matter, step one is to remove and inspect.

OK, I spoke from my early experience with transmissions, years ago. From what I can see on the RealOEM parts site, I now see BMW does use a needle type bearing for the torque converter neck support in the front pump assy. Not sure if they use one, but many external shaft seals use a tension spring coiled around the inside of the seal lip to help exert pressure between the lip of the seal and the shaft it is sealing. I have seen this spring become undone, and allow the seal to leak because of the fluid pressure behind the seal. Not sure if this is the case. Anyway, I will refrain from any further speculation, given my 'ancient' knowledge base.

[rf900rkw]

Sorry, didn't mean to come across that way. I tend to be excessively terse when posting from that phone. Bushing walk is a common cause of sudden seal failure, as you said. And it isn't just the antiques; the newish Mercedes 7 sp auto is suffering premature failure ( under 60K miles) for that exact thing. ZF has used a caged needle bearing there for a bit now. The GM units have a bushing.

Whatever it is, if the fluid is coming from inside the bellhousing, the unit has to come out.

[TechWrench]

Sorry, didn't mean to come across that way. I tend to be excessively terse when posting from that phone. Bushing walk is a common cause of sudden seal failure, as you said. And it isn't just the antiques; the newish Mercedes 7 sp auto is suffering premature failure ( under 60K miles) for that exact thing. ZF has used a caged needle bearing there for a bit now. The GM units have a bushing.

Whatever it is, if the fluid is coming from inside the bellhousing, the unit has to come out.

Hey, its cool. The last thing I want to do is give out bad info. I jumped in a bit to quick, with an opinion based on incorrect info on my part. I respect your correction, and don't take any offense when someone tries to enlighten me. After all, that's what most of us are here for.

[eva89]

Yeah...my transmission shop (he has a lot of experience with BMWs) is removing the transmission next week. I'll keep everyone updated once I know what the problem was.

[danno14]

and???

[eva89]

Update:
My mechanic called and said he had the transmission out of the car, and wanted me to look at it. When he showed the transmission to me on the bench, the torque converter was seized to the front shaft of the transmission. It must've ran low enough on fluid to cause everything to heat up and weld together. So, I have to put a transmission in the car.

Used transmissions appear to go for upwards of 1200 - 1500, and then still require service and installation, and the fluid is VERY expensive...so I decided to go with a replacement remanufactured unit direct from ZF. My mechanic said he can have me out the door with the new transmission for about $3500. Not what I was hoping to hear....but I think the price is reasonable. That includes a 1 year unlimited mileage warranty on the reman unit.

I should have the car back on Wednesday, I will update when I get it back!

[rf900rkw]

Without seeing detailed pictures of the damage, and exactly what is stuck where, I can't say what went wrong. But I can guarantee it was not from low fluid. Not unless you've been driving the car for a while with it slipping badly. Lube oil to the stator clutch and converter support bearing is via the converter feed itself. If you restrict the converter feed, the car quits moving.... quits moving right now, long before any physical damage is done. The reason I mention this is if the root cause is not located, the new unit may well suffer the exact same fate.

[eva89]

Well...I was driving it without fluid for a while, I think. I thought the rear main seal of the engine was leaking....and then it stopped. So I kept driving it. And the car eventually did stop moving....which is why I took it to the transmission shop. It never occurred to me that it was leaking transmission fluid because it was not red. And there's no dipstick to check the fluid level.

[rf900rkw]

That's a bit of the chicken and egg thing there. It was leaking because it was damaged by low fluid that was caused by leaking....

Most likely whatever cause it will be swapped out with the transmission change. Hopefully your man has a cooler flusher. If the cooler is solid and nothing strange is wrong with the engine <-> transmission centering, then it should all be good.

And as an aside, $3500 out the door is not a bad price at all for a quality rebuild. People pay more than that for a Ford now-days.

[eva89]

I'm supposed to get my car back either this afternoon or tomorrow morning. I can't wait...it's been almost a month since I drove my car!

[va525freak]

Hey,

I am new here but I have very similar issue. Here is rundown:

2001 525i with 207k miles. About a month ago I was driving and heard a funny sound like a whining of a pump, pulled car over immediatly and had it towed. Discovered front seal blew out so had someone replace seal for $300. During the replacement he noticed the split needle bearing was frozen to input shaft. When I got car back from him I performed the refill procedure per Bentley manual and I used the Castrol brand that is compatible "Import Multi-Vehicle".

After filling tranny, I noticed a loud whining sound coming from engine, torque converter area - which was different from when I blew out seal but definetly a sound that was never in my car prior to front seal breakdown. To backtrack - guy did not replace split needle bearing, instead he sanded as necessary to free it up. (BAD CALL IMO). I was on another BMW forum asking and asking about this loud sound I was hearing, almost like a turbo but not quite. They said check fluid, or maybe air in system, or maybe just need to drive it and see what happens.

Prior to my test drive I was skeptical - I knew it was not right due to the sound but could not find anyone to diagnose the sound. Actually here it is:

They will not let me post due to being a new member

I thought perhaps torque converter was faulty/or installed wrong or bearing was FUBAR and needed to be replaced.

During test drive (tonight) car shifted from 1-2-3 fine but still had whinning sound and when I pulled into drive way seal was busted and fluid was rushing out. FAIL lol.

I am inclined to think that the pressure is blowing out the seal, meaning pump is not able to freely pump fluid through tranny -or- bearing that was not replaced is causing the failure.

My question for you guys is should I remove tranny and replace seal and bearings this time? Any way to diagnose a bad torque converter? tranny pump? I thought if the tranny pump was good then the car would drive, maybe get the tranny completly flushed out?

One other thing - guy who did seal noted I had no metal shavings or burnt smell in transmission at filter but it was completly blocked with fibers from plates.

Thanks for any help. I am not in a position to drop 2-3-4-5k on a xmsn so I will sell car as is for no money at all or attempt to fix but I need some expert opinions, guidance. I have another car so if I can fix without a major spend I will put in the work.

[rf900rkw]

Number one. What transmission? '01 had both GM and ZF.

Number two. loud whine means DO NOT DRIVE.

Number three. Seal blow-out means transmission failure. Bearing failure means transmission failure. "fibers" in the filter mean transmission
failure.



Also, I'm curious on what exactly got sanded down. There are no needle bearings in that area on either box.

[va525freak]

Number one. What transmission? '01 had both GM and ZF.

Number two. loud whine means DO NOT DRIVE.

Number three. Seal blow-out means transmission failure. Bearing failure means transmission failure. "fibers" in the filter mean transmission
failure.



Also, I'm curious on what exactly got sanded down. There are no needle bearings in that area on either box.

1. ZF 5hp19 model
2. Agree but did not know what else to do
3. Seal blows out does mean transmission failure but what in particular? Bearing is the split bearing that contains needle bearings inside, the part number is 10.10/150 - breakout calls it a needle sleeve that goes into pump assembly. needle sleeve is followed by snap ring, followed by seal. In order for seal to blow out I would think both bearing has to push out, which pops snap ring, then blows seal. He said he reworked bearings and sanded input shaft and bearing surface.

I am confused what you mean by transmission failure - other than the obvious, for instance fibers in filter are due to wear of clutch plates right? which is normal given the mileage of car. If bearings are bad then wouldnt they heat up and creat the loss? Or are you saying that the internal workings of tranny are creating back pressure which is forcing bearings, snapring, seal to malfunction?

I appreciate your insight and know you are much more knowledgeable than me on this and I am trying to understand the system and develop a stradegy to fix my problem. Thanks for the help

[dumblucky]

so I decided to go with a replacement remanufactured unit direct from ZF. My mechanic said he can have me out the door with the new transmission for about $3500. Not what I was hoping to hear....but I think the price is reasonable. That includes a 1 year unlimited mileage warranty on the reman unit.

I should have the car back on Wednesday, I will update when I get it back!

so how much is a zf tranny without the aid of a mechanic

[rf900rkw]

10.010/150 is a wave washer that acts as a spacer for the seal. The bushing behind that supports the converter is pressed into the pump housing. It will not come out. If it did, there is the reason the front seal was pushed out, and the pump is now history. ZF does not service that bushing separately, hence it's not in the parts illustrations. There are replacement oversized bushings, but they require extensive machining.


Clutch fibers. People often assume clutch wear is linear. It is not at all. I often hear "well, it went 200K miles, of course it's worn out". Not true. If the unit had clutch failure at 200K miles, then at 199,995 miles the clutches were still like new. I'll repeat. Modern clutches in modern fluid do not wear. Failure is sudden and is caused by external forces, be it a pressure loss or mechanical failure/bind. If you have clutch material in the filter, then you have a failed clutch somewhere in the unit. Now, that clutch may well have been inside the T/C.

Anyway, whatever the deal, the damage is more catastrophic than just a simple seal failure. Something forced the seal out. And then there may be more damage from the sudden loss of fluid (all it takes is one good slip to destroy a clutch stack), and/or driving it with a mechanical whine.

[va525freak]

10.010/150 is a wave washer that acts as a spacer for the seal. The bushing behind that supports the converter is pressed into the pump housing. It will not come out. If it did, there is the reason the front seal was pushed out, and the pump is now history. ZF does not service that bushing separately, hence it's not in the parts illustrations. There are replacement oversized bushings, but they require extensive machining.


Clutch fibers. People often assume clutch wear is linear. It is not at all. I often hear "well, it went 200K miles, of course it's worn out". Not true. If the unit had clutch failure at 200K miles, then at 199,995 miles the clutches were still like new. I'll repeat. Modern clutches in modern fluid do not wear. Failure is sudden and is caused by external forces, be it a pressure loss or mechanical failure/bind. If you have clutch material in the filter, then you have a failed clutch somewhere in the unit. Now, that clutch may well have been inside the T/C.

Anyway, whatever the deal, the damage is more catastrophic than just a simple seal failure. Something forced the seal out. And then there may be more damage from the sudden loss of fluid (all it takes is one good slip to destroy a clutch stack), and/or driving it with a mechanical whine.

Thanks Randy - a new transmission is in order?

[rf900rkw]

At least a disassembly and inspection. I'd say at a minimum your looking at a new or rebuilt pump assembly. All this based on your description of the problem, of course.

[va525freak]

At least a disassembly and inspection. I'd say at a minimum your looking at a new or rebuilt pump assembly. All this based on your description of the problem, of course.

I am removing tranny/TC today, I will take some pics and show you what I have

In process o removing transmission, next step is removing drive shaftbut I have a couple of questions:

1. Per Bentley Manual 240-12: Remove acces plug cover plate on left side of bell housing to get to TC bolts - cannot find this, the pic sucks, can you guide me there?

2. Per same page of manual, next step: Place BMW special tool 11 7 370 between engine oil pan and subframe - why do i need this?

3. Same page last step, how can I hold TC on as i removee tranny if I do not have 24 4 130?

So far everything is going as planned, exhaust came out easily and electrical harness, linkage, cooler lines have not given me any problem, front stabilizer is swung up and away.

I am assuming I should mark the drive shaft as well so that it is installed in exact location when it is time and yes I need to get new bolts for this per the manual.

Any other tips, tricks, etc would be awesome

why cant i add pictures?

I have the torque converter and transmission out the car

Randy,

Got the tranny and TC out, umm any obvious signs to look for? I wanted to send some pics but I do not think it is allowed.

At least a disassembly and inspection. I'd say at a minimum your looking at a new or rebuilt pump assembly. All this based on your description of the problem, of course.

I have pics at http://www.bimmerfest.com/forums/sho...=663205&page=3

enjoy and let me know if you need more or can guide in any way

[va525freak]

Bump?

[rf900rkw]

Send a full resolution version of the first two (the T/C) to my username at ascoff.org

Pictures received.


That's pretty fugly. The rough piece on the converter neck right behind the seal is the remnants of the pump bushing. It is a babbit lined steel backed bushing that is supposed to be pressed tightly into the pump housing, and the converter spins inside of it. I assume this is the part your friend tried to sand?

It's all garbage now. The converter must be replaced. The pump must be rebuilt or replaced. Then there is the potential for damaged clutches deeper in the unit caused by the (multiple) loss of fluid. All it takes in one good slip and the clutches can be irrevocably damaged.... with the ultimate failure months away yet.

And, just to complete the bad news... the pump is not a simple item to change.

[va525freak]

Sent