Lurching on the XK8 seems rather common, at low speeds and more often from a cold start the gas pedal will be unresponsive for a short time before the tranny decides to engage and you jump/lurch forward. In my case I also get ABS/trac error messages, which may or may not be related to it.

Anyways, are there any success stories of fixing the lurch herein? By in order of pain from least to most:

a. Reprogramming the transmission (cost?)
b. Having the ECU refurbished, ~$200?
c. Replacing the tranny fluid, ~$200
d. Refurbishing the tranny, ~$1000?
e. Something else?

Cheers!

 

Just drive more aggressively more often and the tranny will pick up on that after a while. That should minimize if not eliminate the lurching. Also, S mode and the J-Gate are your allies.

 

Had a lot of lurches and gearbox/transmission codes when I bought the car last year. They were due to low levels of transmission fluid because of a leaking seal. The previous owner had been over-filling the gearbox so it never ran out of fluid.

Got the leak fixed and the transmission fluid drained/flushed, and the gear-change has been perfect ever since. The car has done 98k miles, by the way. From your list, I would say c) and d) were applicable in my case (cost was $600 in all).

If you haven't done so already, I'd get a code reader and find what the diagnostics are saying: may be worth a $50 investment if it saves you $6000 for a new transmission/gearbox. And it'll be useful for other problems in the future.

Enjoy your car!

Best wishes, Colin

 

Hello people,

I am experiencing the same issues regarding initial delay then drive engagement.

There is a suggestion that more agressive driving may 'teach' the system and partially eliminate the problem. I am unsure how to proceed with this process as I have always been careful to avoid the 'kick in the back' that preceeds planting my foot from standstill as I feel that surely there must be something in the drive chain is going to complain sooner or later. I would ideally like to get serious and sustained acceleration without the 'thump'. Is this possible?

I had the local (and good) indy check gearbox levels and they said levels were fine but the fluid was red??? They didn't advise a change though.

Any advice appreciated.

Cheers to all

Larry

 

I was getting the after-complete-stop lurch. I had my transmission fluid replaced and that fixed the issue.

 

 

Howdy: I have a 99 xk8 convert with around 84000 miles. Had the car about 3 years now. I use to get the "lurch" every now and then and quite pronounced. Usually coming away from a rolling stop. I did the tranny fluid and filter last year in the spring. I have also reset putting the neg disconnected to the positive. I have not a lurch since. Maybe nothing to do with what I did but it seems to have gone ( knock on the wooden dash )

 

Yeah, ignore that suggestion. I misunderstood what the problem was.

 

Great, so filter, gasket and fluid replacement then. I'll try to find a shop that can do it, I see that filter + gasket kits are ~60 bucks. As for fluid, is Mercon V ok or go with oem? Very out of warranty.