Hope you can shed a little light with a problem I am experiencing because I have little to no experience with transmissions.

When driving the 2000 SType 3.0 at speeds between 52 to 57 I have a slight pulsing that I can feel and it does not affect the drive and I do not this it is from the engine. When I accelerate gently it downshifts and the pulsing quits. I changed the oil and had no noise in the engine I then put it in gear and accelerated a little and no pulse. I then took it out for a run with the sport selection on and off but no change. I have done a search here and on the internet and could not find a thing on it. I had checked all over the engine with a stethoscope and could not find a thing that was out of the ordinary so when. I plan on installing the radio noise units to see if I can track it down but my guess is that it is in the trans or the torque converter but that is a guess. Any suggestion would be greatly appreciated.

 

Is it the torque converter going in and out of lock?

This has been described in the older ZF like in your XK8.

 

Mine in My '03 STR does something similar. I read it was caused by a programming issue and need to have it updated at the dealer. In your case You have the 5 speed Ford transmission, don't You? That wouldn't be in the service bulletin for the ZF HP26.
But it sounds like the torque converter lockup issue I think Mine has as well.

 

The 5R55N uses a seal on the gearbox shaft to engage the lock-up torque converter.
TSB S307-03am describes the fault P0741 (CLUTCH DOES NOT ENGAGE) but you might have a worn or damaged seal causing the torque converter to 'hunt'??

Maybe the valve body is faulty/leaking for the TCC fluid circuit.

Just some ideas.

bob

 

Of all things I did not look to see if a TSB was in this problem with the 5R55. Because the TSB exists I should assume that it has been an issue. What surprises me is that they say the seal might have been omitted.

Link http://jagrepair.com/images/TSB/TSB2...TC%20P0741.pdf

In my situation I do not have any codes and am a bit confused on what direction to go. I have IDS and can attempt to reflash the transmission control or I can replace the valve body or I can bite the bullet and pull the trans replace the clutch seal, valve body and reflash. I had already replaced the transmission filter and fluid but experienced little change but do not have a problem in doing it again to get it right.

Thanks Bob!

 

Gus, if it's your 2000 S-Type you can't reflash the trans because it hasn't got a computer in it. The 5R55N is controlled like the engine by the PCM.

 

Well that is what I get for having the XK8 on the brain!!

I am thinking the valve body would be first on my list and it that does not fix the problem then I will remove the trans and replace the seal at the torque converter. The trans shifts properly and smoothly so reflashing the PCM will go to the bottom of the list.

Thanks for the input and I will try to provide an update.