ditchpickle

Well, I dont know what to tell you. My torque converter was rebuilt. I took the car from him after the initial valve body work and other troubleshooting (none of which helped) and returned a week later for the torque coverter job. The torque converter was removed on a Monday sent out for rebuild and reinstalled on Friday. He explained to me how it needed to be slightly resurfaced because of the metal on metal contact. He also explained how these torque converters require a qualified ZF tech to rebuild due to the fact they are fusion welded when reasembled. There are many more details to this story that have me convinced the tranny guy I used is honest and honerable. Have you rebuilt or cut one of these apart? Do you have experience with one of these TC's going metal to metal and destroying the fluid in 10 min.? If so I appolagize. If not I sugest you refrain from calling someone a liar. In any case my car works great and I am happy. I thought I could maybe be of service to others who are experiencing this. But apparently the local experts here have it all figured out.

Always Overcharged

Tozo what did you actually do to the valve body to assist lock up??

Always Overcharged

All the work done on the forum has been recently making more sense and I personally have seen logs from the car Tozo is talking about both before and after the recent modification and there is a huge improvement and this is confirmed by the owner who drives it.
There have been many suggested causes and due to the way these cars operate many of these may have validity as so many things contribute to the signals controlling the TCU.
Tozo's recent mod may well bypass them all and force the trans to behave better without having to worry about these signals being depleted by wear/age etc.
I too have reservations about any torque converter running metal to metal as there would be huge heat build up.
But if your car is running better then great but please help the forum by advising if and when the hunting returns.
Often a reset can give faulse hope and even some members here perform regular resets to improve drivability.

Always Overcharged

TPS replacement and again now.
I would love to compare with some I have from other cars.

tozoM8

I know, it's easy to misunderstand my English.
The TC clutch is locked by springs. Fluid pressure keeps it open. I have pictures how the TC looks inside, I will post them. There is clutch material glued to the back of the TC (engine side)inside. The clutch plate is steel. It is forced against the clutch material by springs and fluid pressure. The VB sends fluid with higher pressure between the clutch plate and the back housing to keep it open. When they rebuild a TC, they cut it open like a bagel. They remove the clutch material and glue new in. Sometimes they replace the bearing too if it is necessary. When all done they weld the housing back together and rebalace the unit. If you see two welds on it, you know it's been rebuilt.
Try this. Forget what I've said and think about this. You accelerate, your engine put out 300 HP. Do you think a steel to steel clutch in the TC can transfer the power to the transmission without blowing up?

ditchpickle

I will advise if it returns. But I have vag com and I tried a reset (more than once) it did not help.

ditchpickle

I can tell you this, I was told if I had let it go any further it would not have been rebuildable. Due to the fact that too much would have had to be removed to resurface the clutch plate. I picture it like this, the TCU comands a certain slip rate, say 300rpm, the TC is worn and cant hold that rpm, but it tries and gets to 500rpm before it holds now it realizes its too high, backs off and now it drops to 100rpm , only to start the hunting over again. Maybe I am wrong. But it sounds good.

ttuling

At least one Kevlar based clutch material has a wet dynamic coefficient of friction of 0.10 to 0.15 (http://www.tribco.com/wetcluch.html) and up to 0.17 static.

Some kinds of steel-on-steel, can match that coefficient of friction if "greasy", and could reach 0.78 if dry. (http://www.roymech.co.uk/Useful_Tables/Tribology/co_of_frict.htm#coef)

So especially if the driver rarely deployed full torque, I could believe that normal lockup pressure might be enough to keep the clutch from rapidly destroying itself after the friction material is gone. And when a wet clutch slips, an oil film separates the two pieces and transmits the power, right?

There's probably something wrong with my analysis, and like you I suspect most hunting is caused by something in the valve body. Nonetheless, it was worth reporting that ditchpickle's converter clutch hunted when it had no friction material left, even if that doesn't happen very often.

Tom

Always Overcharged

so slip would have been more than in a "well" car.
Lots of slip probably means lots of heat generation as the tc slips in and out so seems likely it would have shat itself fairly quickly if truly metal on metal.
This statement was probably an embelishment from the
TC rebuild guy.There may well have been severe deterioation of the TC lining exposing some metal areas.

dS8

Me three. Send info on trans guy. I also are in Mpls. I would love to have speaks with him.