Transmission Leak - Fix or...???

StudioWizard

Member
 Los Angeles, CA, USA
Hey everybody

I have a 2005 2.5i 5-speed automatic.

My mechanic told me today that my transmission has a small leak. He said it's hard to know where the leak is originating - it could be a seal, the torque converter, a pump, etc. He says it'll probably cost about $1000 to repair, but that it's possible there's transmission damage already, in which case, it's wasted money. His recommendation was to keep driving it until the transmission eventually fails which could be somewhat soon or 30,000 miles from now.

Before you give me your opinion, there are a few other details to add, some which may or may not impact this issue. But here goes:

If I'm driving at a slow rate of acceleration, esp on any incline, when the car shifts into 4th or 5th, there's a growling noise momentarily. There's a lot of torque going on at lower RPMs and going uphill. OTOH, if I drive in Sport Mode, the growling NEVER happens no matter how slowly I accelerate or if I'm on an incline.

Secondly, there's a pretty strong smell entering the cabin that starts to happen after driving for awhile, esp on the freeway. It kind of smells like oil, but I'm not 100% sure. If I'm on a road trip, after an hour or two, my eyes my get a little itchy. If I turn on the AC and blast it, the smell starts to go away. Or, if I have the top down, then of course it just wafts away.

Third, when the car is in-gear and accelerating, there's a click click click click sound happening. This only happens when the transmission is engaged. It NEVER happens if hit the gas in neutral. One mechanic said it's the belt tensioners. My regular mechanic said it could be a bunch of things, including lifters, an alternator going bad, etc, and not to worry about it until a code shows up or something fails. Somebody on one the threads here was talking about this same clicking sound on their car and said it's a bad torque converter.

Lastly, I'm not sure if the car is sluggish or normal because I bought the car several months ago and it's always driven like this, so I don't know if it's supposed to be zippier than it is or not or if the transmission isn't working optimally.

Overall, it runs really well and I've fixed all engine leaks, replaced fuel injectors, had all the fluids changed (including transmission and differential), put on new tires, etc. This is the last major issue..... (famous last words? haha)

So what I'm wondering is if all the above things might be related to the same issue and if it might be worth spending the $1000 to see. Rebuilding the tranny is about $4k according to my mechanic. It's a tough choice....

What do you think?

Thanks!!
 
StudioWizard said:
Somebody on one the threads here was talking about this same clicking sound on their car and said it's a bad torque converter.

That was me. The torque converter doesn't seem to be a common problem from my google research. Seems I may have just been unlucky.

If it sounds like this and you have no low end power took quite a bit of gas to pull off then its likely to be the torque converter. That kind of ties in with your points 1 and 3. My issue was the stator bearing/freewheel once that goes it doesn't perform the any torque multiplication that it should.

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As for the oil smell im not really sure.

The transmission leak could be on the pump/torque converter interface but if it is here then its going to be a pretty expensive fix as you pretty much have to open the gearbox to get the pump out then have the bushing re-machined and replaced. It will need to be sized to the torque converter interface. That50sKid on youtube has a video on getting the pump bushing re machined amongst a bunch of gearbox rebuild videos.

21:28 he talks about the transmission pump.
[youtube]zDQ3RBZFLIE[/youtube]

As for the gearbox rebuild we are lucky in the fact that it is quite an old box so is relatively simple for an auto (not that I would want to go messing around in there) there is not a-lot to go wrong unless you get blocked fluid paths. The clutches will wear with low fluid and you will get slipping in gear if that happens.

You could always try the easy things first to see if it goes away, Belts and tensioners are easy to do and cost me about £150 Could have got the parts cheaper if I got them online but went to a local motorfactors instead. Lifter tick do a search on here but im pretty sure a long ish drive with the engine over 3000rpm to build some oil pressure should cure that.

You could check the flex plate bolts on the back of the torque converter those are accessible through an inspection hole in the transmission.

It could also be a blocked cat or a broken bit of the catalyst rattling around in the exhaust, the primary cats are up front on the right hand side of the engine bay so are quite close to the gearbox.

That may or may not help but it sounds like one of those jobs where a mechanic would suck his teeth and go ohh thats gonna cost ya! Do you have any ZF specialists that could take a look near you?
 
Thanks for the great info, Matty_Z4!

Yes, my car makes almost that exact sound as yours, so it's clearly the torque converter. In fact, I took it in to a transmission shop here in LA. They did a full diagnostic on the transmission and found a leak at the pump seal area. They also confirmed the torque converter was making that noise and that the smell was coming from drops of t-oil dripping on the exhaust. They said the car is slipping a bit when shifting into 5th gear.

They gave me an approximate quote to rebuild the whole thing with a 1 year warranty for about $4400 out the door. They said I could wait until it fails, but then it'll probably cost a lot more to repair since it can damage other things including the casing. Then, we're looking at more like $7-8k. YIKES!!!

I can call around to get some other quotes, but I don't think I'll get a quality job done for less than $3500...

Thoughts?
 
I think (and this is just my opinion) that I would change the gearbox oil and filter

Controversial- on one hand the issues may be caused by low fluid, but changing fluid may also completely bring forward more terminal issues in the gearbox

But- chances are that it’s shagged anyway so a change of fluid may shut a few of those issues down and accept that you’ll always have a leak that needs topping up
 
I already basically did that a few months ago. The problems are definitely NOT caused by low fluid because I completely had it changed a few months back hoping that might solve the problem, but it remained exactly the same. The transmission definitely hasn't gotten worse that I can tell over the time I've driven it.

Also, the tranny guy said what you just said... that changing the fluid will actually make it worse. Who knew??

So, it's really either pony up the cash ($4500) or let the transmission die. OR, I can try to sell it, but that won't go over well.... I can give it to the state and they'll give me $4500 cash for regardless of the condition, but I have to buy an EV.
 
Given the high prices in the USA for a Z4, UK cars worth £3000 to £4000 for that year, it would make sense to repair the transmission and keep the car on the road assuming the engine is still okay. However, as the car is running, I would leave well alone and start saving the $4500 for a new transmission.
 
StudioWizard said:
Also, the tranny guy said what you just said... that changing the fluid will actually make it worse. Who knew??

The fluid change may have highlighted the slipping clutch in 5th gear as from what I understand if a trans is badly worn clutch material builds up in the fluid and kind of hides the issue because things still work. Then changing the fluid clears out all of the suspended clutch material and now the actual clutches don't work because they are worn.

At $4400 for a rebuild I would be looking at a 2nd hand transmission at a breakers yard as that sounds like its almost 70% the value of the car. Am I right in saying that the E85 is $7000 - $8000.

This one is in Texas and im sure you can find a much lower gearbox
https://www.ebay.com/itm/235266383923?fits=Make%3ABMW&hash=item36c6f82033:g:mUgAAOSwezBij4HT&amdata=enc%3AAQAIAAABABrQlV9eFDdXMHdr6Au%2F1xoFcxz044nY%2FvfG1AzeWznOY59gNz78MU34H9FI9yaj9EzVs2C7tyB2bEU%2BWmgJp2htVFBPBLfFHRrAHBXqPEZNbK1MbTMxhjE5tWtr1ccS4%2F1g7dzF%2BjrXSCpriYCQiSierJ0jLDpLK2pTy%2B4N8DwbLZCSCrUv2MX%2FgF1RRltWx4NEnAriRvY8EznQjwn0pRKk9i%2Br56pUL3zk0Q99JtCBUzRlML3K1tFej8uPivUmnAHneec9MI4p2tsvV3aNzkH8HCgvNPMAQD6LWlvJKTAz8dGHdfUq20Fw3E67p59ZGoVrpWw0d77oj3Nfl457aPo%3D%7Ctkp%3ABFBM2IbymfNi


If it was me and I had the space (which I dont ) then I would probably end up getting a 2nd car so I can take the Z4 off the road and then get on youtube and have a go at a DIY rebuild. If space is limited like me then it would probably make sense to get a 2nd hand transmission and torque converter and get it fitted (or fit it yourself if your handy)

While you have it all apart check the Flywheel, Flexplate and engine rear main seal.
 
raymond.harper said:
Given the high prices in the USA for a Z4, UK cars worth £3000 to £4000 for that year, it would make sense to repair the transmission and keep the car on the road assuming the engine is still okay. However, as the car is running, I would leave well alone and start saving the $4500 for a new transmission.

The car overall is in pretty good shape. The engine has had all leaks fixed and sounds pretty good, the convertible top works perfectly, has brand new Michelin tires, etc. The car's 165,000 miles on it...

Thanks for the advisement - I probably will get it fixed.
 
[/quote]
At $4400 for a rebuild I would be looking at a 2nd hand transmission at a breakers yard as that sounds like its almost 70% the value of the car. Am I right in saying that the E85 is $7000 - $8000. [/quote]

It think it depends on the mileage. Mine's got 165,000 on it, but I will have fixed everything on it... literally! My goal is to not spend too much more than the car's value. Fixing the transmission will put me pretty close when all the other fixes are added up. It's not a hard/fast goal because you can't put a price on enjoyment really....

[/quote]
If it was me and I had the space (which I dont ) then I would probably end up...
[/quote]

Unfortunately, I don't have a good space nor the time to do it. I'll probably just suck it up and have a reputable shop do it with their warranty.
 
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