I'm new to the forum and would really appreciate some honest advice.

I have a L322 RR TD6 2004, its done 118k miles. The car is vibrating between 30-55 mph, like its selecting the wrong gear. If I accelerate hard, its fine but as soon as you accelerate less then it drops down to 1500 revs. The mpg has also been bad on it lately. I've had TSF come on intermittently over the past 2 years and have had the gearbox oil & filter changed 3 months ago (was told by indy that that would solve the TFS issue). It was after the oil & filter change the vibration started. Now I've been told by indy that the LUC is going on it.
Should I get the whole gearbox replaced or just the LUC?
Thanks
Kim

Welcome to the forum Kim .
The lock-up-clutch is in the torque converter .
My advice would be to replace/refurbish the torque converter , and do one or two gearbox drain-fill .

Hello and welcome Kim.
Given the age of your gearbox unless you know it has already been refurbished or replaced I would look at a full refurb. Search gearbox and be ready for some tales of woe. Mine was a blue one!

+1 to the above. I would get the g/box refurbed before it goes bang!
There's more than just the tc that can go wrong on these gm g/boxes as well.

"gm g/boxes" ....

Ignore me , I was thinking about my car with its zf .
Again .

I keep meaning to ask a few of the good morning truck guys at work about this box , as I never hear anyone driving a gm truck having tranny issues and most trucks are over 250k ....

^ The GM "box" used in the TD6 L322 was also used in the early X5 desiesel but it was designed for a medium sedan and is pants in a 4x4 because it has to work so far out of its designed parameters , not GM's fault really just BMW pushing their luck . 2008 MY Supercharged
Rimini Red / Jet
four zone climate
remote park heater
and no ugly kid windows.
magnus satis quod turpis satis

Couldn't agree more.
Such a shame as the td6 engine is a good engine and capable of more power.

Any shudder when the LUC is engaged can also be due to imbalanced injectors.
Before you start changing parts, have someone check what the injector correction values are. Anything over 3mm^3 will start causing shudder.
-
DJ

i had the same problem in november ,mine was diagnosed as the torque converter ,i got a torque converter of ebay ,bmwe39man ,his name is doug he knows his stuff he recons them useing uprated plates and gives 2 yrs warranty give him a call great bloke to deal with.

I risked just getting the LUC replaced and a few months later had to return for a transmission rebuild, including the torque convertor again having to be opened up and cleaned out.
While the transmission is out of the car, best to have the transmission stripped as if the LUC is worn there is a good chance one or more of the other clutches will also need replacing.
Also any bits of metal or friction material get pumped through the whole transmission, the filters are only a screen.

Totally agree. Mine had new valves, new clutch plates and two springs in the accumulaters.
so rebuild is best way to go.