Hunting and Thumping
 

Hello, I have been lurking this forum for about a month now. I bought a 99 A8 for what I thought was a steal. Shortly after, I discovered it had a transmission problem. Yes, the dreaded low speed hunting accompanied by the cruising speed off throttle thump. Virtually the same thing I have read here many times. I found an excellent tranny mechanic who had some experience with these transmissions. His first thought was a sticky valve in the VB. He removed the VB and indeed found the valve he suspected sticking. He corrected it- no help. He then checked out the TPS, tried a new computer, lock up solenoid and speed sensor- all no help.(he removed all these parts and reinstalled mine, no cost for parts to me) He advised me it would need a torque converter. I had him do the job last week. The transmission now works perfectly. He removed my TC and sent it to be overhauled, according to the guy that overhauled it, it was metal on metal, no friction material left at all. My mechanic feels that continued use of the car (TC sending metal through the system) would have eventually caused more damage. Total cost for everything I had done was about $1600. I would recomend this guy to anyone, if you are in the Minneapolis area and looking for help I can hook you up with him. He has created a database of problems along with healthy data from my car. He also told me that the guy who rebuilt the TC has done 20 trans rebuilds recently 19 of them the TC was fried. Long winded I know, but if you suspect your TC I would change it sooner than later.

if you did the TC, why not rebuild the clutches on the tranny?

Sounds interesting, but I would like to hear your report in a month
 

To see if it comes back or not.

Re: Sounds interesting, but I would like to hear your report in a month
 

Not quite sure why the TC would grenade itself again in a month? But I will definatley let you know.

Re: if you did the TC, why not rebuild the clutches on the tranny?
 

I considered that. I asked the tranny guy that same question. He said he did not see any abnormal wear material in the pan and said he saw no reason to do it.

The TCU will learn and the hunting may begin again
 

The throttle position sensor fix on my car worked great, but after a month or more it is now going back to its bad habbits more and more.

I have a rebuilt TC in my transmission, no change.

Re: The TCU will learn and the hunting may begin again
 

Sorry to hear that the TC did not fix your car. Did it initially correct anything? Do you know the condition of the removed unit? Are you confident in the rebuilt unit? I only ask this because I know the condition of mine. It was totally shot. The same unit (rebuilt of course) is in my car and it is fixed. As I said my tranny guy was really surprized when the sticky valve in the VB did not fix it. He said the last one he worked on had the same issues and correcting the sticky valve fixed it.

Please send contact information. I am also in Mpls. Thanks

I don't get this.
 

1; Only big companies with good reputation rebuild TC. I know for a fact, they don't rebuilt TC if it is steel to steel.
2; There is no way it was steel to steel. It wouldn't hold lockup, it would burn up the fluid in 10 minutes (ruining the tranny) and it would be extremely noisy. We put a brand new TC in Tony's car two weeks ago with a rebuilt tranny and it haunted right away. After the valve body modification (last Saturday) all haunting is gone. All I have to figure out how to move the shift points a bit higher.
Don't misunderstand me, I am happy if you happy. I just don't get it, why they have to make up stories to make the customer happy.

2nd. I just showed Tony how flat an O-ring can be after 100K miles.
 

Unfortunately ZF uses O-rings instead of D-rings. after 100K O-rings can blow any time. Eddie was working on an Mercedes ML last week and all the seals were in good shape. They use D-rings.