I've noticed an ever so slight pulsing / surging (surging is really too strong a word for what it's doing) on my XKR the first few miles at 20-50 MPH speeds as I'm driving. I notice it most as I'm maintaining my speed (not accelerating). Once it's warmed up it's fine, just the first few 'cold' miles.

Has anyone else had this or have any ideas?

 

I have something similar. It was there when I bought the car and it's still there, even after a trans fluid and filter change, 20k miles and installing a twin screw.

The thing I've noticed is that it seems to happen when shifting into 4th gear. There is sometimes even a pulsing shudder almost as if the transmission is engaging and disengaging that gear and letting it slip just a little.

Once warm, it is non-existent and there is no apparent slipping of the transmission or surging after a few miles drive so I've never worried about it too much.

It is strange, but very consistent and a relatively minor annoyance so I figure that some day, when I have to rebuild the transmission, that it will get taken care of then.

 

Hi Guys, I have an '03 XK8 and mine has always done the same thing you're describing. Only does it when cold... first few miles... after that, she's fine all day.
I have been told some early '03's had a torque converter issue that causes this symptom. The thing is I've also read that these ZF 6HP24 trannies have all kinds of adaptive capabilities as well as monitoring so it can limit slip under certain conditions for optimum efficiency... so it may be normal. I live with it... not a big issue... it's not gotten any worse so, for me it's a non issue.

 

My STR exhibits this behavior as well.

 

Thanks all for the replies, nice to hear I'm not alone with this behavior.

 

I had this with my 131K mile engine and just noticed it with my"new" 50K mile engine this morning. So its not caused by the engine, but instead by either the tranny or some electronic thingy (technical term - lol).

 

Sounds like TC (torque convertor), there's a TSB about it but without a good warranty probably best to ignore it.

 

Hi,

My XKR does it too. Really noticable with a louder exhaust. Do you have a link or detail on the TSB at all?

Cheers

 

I have had this issue since I bought the car with 62k miles, and had the transmission fluid and filter changed at 69k miles or so (not to address this issue) and the situation never changed, even to this day with 96k miles or so. I have read Audi and BMW forums where people complain about this issue. Some have stated a torque converter replacement helped or cured the issue. I have noticed that if the car is in sport mode the problem seems not to exist, so I leave it in sport mode.

Gus's jag repair site has a TSB for the S type that addresses a surging concern, but the TSB is not very descriptive. http://www.jagrepair.com/images/TSB/...rge%5B1%5D.pdf