shudder

hi all, new to this site. i have a silver 06 T/D auto twin cab(non DPF).

aside from my torque converter shudder, i now have a shudder under light brake application when the car almost has stopped, it will lightly thump thru the car 2 to 3 times. sometimes it doesn't do it but then as you gradually let your foot off the brake(no accellerating) it will thump a couple of times. if i have to brake moderately, it's fine.it could be the auto box, as it doesn't do it if i put it into neutral while coasting and apply the brakes, and when it thumps, it doesn't feel like it's trying to fight the brakes. don't know if it somehow ties in with the torque converter shudder? the general operation of the auto is nice and smooth apart from a bit of a wisttle when accellerating.
any clues?

Welcome to the forums Eric, not 100% sure of a solution to your problem so to give someone else a chance to get it right I'll give the thread a bump to the the top of the list.

Welcome to the forum, Eric.

It's possibly that torque converter, or more specifically it's either the torque converter clutch (TCC, which is part of the locking mechanism) or the TCC's solenoid or the valve attached to it.

There's an easy way to check. The TCC is only ever activated when the vehicle is in DRIVE with Overdrive ON. Just flick the overdrive switch OFF so the dash light comes on and try it again - things should be smooth, because the ECU (main computer) will tell the TCM (Transmission Control Module, in the auto box itself) that it can't engage the TCC.

If it's broken, the torque converter needs to be replaced. Since you're probably out of warranty, your best bet is to see if Nizzbits here can help you out with a new one.

If it is brakes it could be something to do with the ABS module or the discs may need machining

definately must be the torque converter for the shudder. the thumping when i roll to a stop hopefully is only cooked a/t fluid. i'll get the fluid changed, hopefully it will fix that problem, but wonder if it may soften the o/d shudder?

While I'm not certain, I believe - because of the circumstances that the shudder occurs under - that the shudder may not be improved (or if it is, not by much).

I have the feeling that the shudder is caused by the torque converter clutch not engaging properly, so it tries to engage then lets go, tries, lets go ... each time it tries to grip the torque converter to lock it, it causes the engine rpm to slow as it aligns the rotation of the engine with the gearbox.

I hope the thumping isn't a drive shaft/uni or something in the brakes. Watch the front rotors on the D40, they're made of Philadelphia Cream Cheese. A crack in the rotor could easily translate into a thump under a braking load.