Torque Converter Issues
 

I have read quite a few threads about the issues BMWs have with their torque converters in relation to the X5 and I am pretty sure I am having some sort off issue with the converter in my 2003 4.4i. (LH40078 I think if anyone needs any more details!) Between the speeds of maybe 30~35 MPH all the way up to just before the torque converter locks at 60 MPH I have a strange shuttering issue. The torque converter locks just fine once I hit 60 and i no longer have any sort of studdering (until I slow back down below 60 and then the shuddering begins again). I have read that one fix is to use Instant Shudder Fixx By Dr. Tranny (Lubegard) and it seems like everything I read said that the earlier you got that stuff in the transmission the longer it kept issues at bay...

So my question is - For anyone who has used the Instant Shudder Fixx - was your torque converter still locking up at 60 before you used the Instant Shudder Fixx, or was it locking and unlocking (shuddering) at all speeds? I am wondering if I have a different issue because my torque converter works as it is supposed to above 60 (at full lockup) but only shudders at lower speeds.

If anyone has had experience with this I would love input. I am planning on adding 2 tube of the Instant Shudder Fix, but if I instead have an issue with a PWM solenoid valve or something valve body related and one of those need replaced I would rather just do that.

How many miles on it? Under light throttle the converter will actually engage after the second shift at around 35-40 mph. If it only shudders during engagement, sure, go ahead and try the shudder fix, it's worked for us here at my shop numerous times. But if it slips and shudders after it's engaged when you try to lightly accelerate, then the converter clutch is more than likely worn out.

The X5 has just over 160k miles. It seems to work just fine after I hit 60 mph like I said, it just does shudder in the slower speeds. I was under the understanding that the converter doesn't "fully" (supposedly it never fully locks, it is supposed to leave like 3% slip or something like that) lock until it gets to 60 mph and that it uses a pulse width modulated solenoid valve to accomplish the partial lockup. I think what I am feeling is the converter lock completely when it is only supposed to partially lock and then it unlocks again real quick and that is why I get a shudder. This would be why I am questioning the solenoid valve. Has anyone ever seen this solenoid valve fail like this or has anyone even tried replacing it?

You could try swapping over your LUC solenoid with one of the other three ‘black cap’ solenoids if you wanted to prove a point

http://i260.photobucket.com/albums/i...t2008/EDS4.jpg

but it’s much more likely to be wear of the LUC friction plate that’s causing the issue. Range Rovers use the same Sachs WA4/W260 S-2GWK (F38 model) torque converter and usually start with the ‘cattle grid’ noise at just over 100k miles.

http://i260.photobucket.com/albums/i...lateinsitu.jpg

The travel of the LUC apply piston is only around 1mm so it’s very sensitive to wear. On the Range Rover the transition from continuous-slip to full lock-up is at around 57mph

http://i260.photobucket.com/albums/i...Throttle-1.jpg

Phil

Thank you very much for all that wonderful information. So I will just add the Dr. Tranny Instant Shudder Fixx and hope for the best. If the Shudder Fix works for me is there any reason I should be set on replacing the torque converter before the shuddering comes back? Worn friction material isn't going to cause my torque converter or my transmission to explode for some reason is it?

The worn friction material won't blow anything up, but it can contribute to a plugged filter and sluggish shifting.

2002 X5 3.0 281,350 miles
2004 325i 120,700 miles

I have only had the car a few months now and the previous owner had the transmission oil changed (says they used the BMW oil, i sure hope he did the filter too, I will have to look at that receipt again) so hopefully the filter is clean, The X5 seems to shift fine at this time. I just got home from work and got the rear up on jack stands and I got the front up on ramps earlier today. Hopefully things go smoothly tomorrow and I will get the 2 tubes of Shudder Fix in the transmission. I will report back with my findings when I finally get it done and have driven it a few miles.

I ran mine for a further 20,000 miles or so after the juddering started and there was still friction material left on the plate when I finally replaced the torque converter

http://i260.photobucket.com/albums/i...plateclose.jpg

You can see the ‘judder’ marks on the face of the LUC piston which engages with the friction plate

http://i260.photobucket.com/albums/i...attermarks.jpg

Just make sure that you don’t leave it so long that the friction material wears off completely and you end up with a metallic debris generator!

http://i260.photobucket.com/albums/i...ps3bfa21ff.jpg

Phil

Well, I have 30 miles on it now... The torque converter lock up clutch seems to be working much better when the car is in sport mode. The torque converter still does seem to have an issue when not in sport mode but the shudders seem much less strong. it was surprising just how fast changes were noticeable. I would say that the transition area around 50 to 60 mph is much smoother. I guess I will put a bit more miles on the X5 again and update if it get any better, stays about what it is now, or if it get worse for some reason.