300Tdi Auto - Torque Converter doesn't seem to be locking up as it should

[ibruceuk]

Hi there,

As the topic title really.

At about 50mph the torque converter should lock up and it does to some extent.  The revs drop and if you let off the throttle there is a definite amount of backlash as the transmission takes the slack up.  So it seems to lock up when decellartating (sp?).  However if I accelerate there is some slip, not as much as when it should be locked up though.

It didn't used to be like this.  Could this be as a result of low transmission fluid?  I've checked the fluid level (there is a small leak) but it appears to be around the maximum mark.  It's really hard to tell though as it's just a smear of transmission fluid.

Any ideas?

[solihull-mick]

Ive had a few with the same fault, one was the sludge filter in the box blocked, the other was a broken flex plate on the converter, does it make any noises the ticking over?

[ibruceuk]

Doesn't make any noise that I've noticed and seems fine the rest of the time.

It started as far as I can remember after using kickdown at just over 50.

Is there any way of checking if it's the sludge filter without dropping the sump.

When it's cold it is very slow at changing gears.  If it was the filter would it do any harm driving it for a while till I find time to do it?

[solihull-mick]

Hi there is no way of checking the sludge filter without dropping the sump, which also means dropping the transmission cross member, as the sump wont clear it, cant see it doing any harm, the other symptom of the filter is slow gear changing and excessive throttle need to pull away when warm, you may find just an oil change will work wonders, the oil should be a nice pink colour, if its brown and smells burn change it first, 

[ibruceuk]

I'll give an oil change a try at the weekend.  The gear changes are slow compared with the V8, but i've not noticed it needing a lot of throttle when warm (although it does seem to 'slip' more than the V8 does).  When it's cold it's really sluggish though.