I have little to pick on with my XJ12, but one item would be the 3-4 second delay when shifting into Drive from Park or Neutral. It has been going on for a while now, and I began living with it instead of looking into fixing it! The trans operates just fine after it engages. The fluid level is good and it is not too old. Ideas anyone? GM 4L80-E transmission.

 

Mine does the same and has for as long as I've owned it. Usually on the first shift into "D" each day...and OK after that.

I think this problem comes down to a weak servo piston seal. Can't quite remember for sure. I researched it once, years ago, and then shrugged it off. Google "4L80E Delayed Engagement" and I'm sure you'll get lots of hits.

There are many little upgrades and improvements for the 4L80E...as you'll see from some browsing and Googling. If I keep my car long enough to need a trans overhaul I'd like to have 'em all done.

Cheers
DD

 

Thanks, DD! I will get to it some time, probably when I decide to change the oil & filter next, but it's not due for a while.

Curious - does the XJR trans come off the line in 2nd gear when in Normal mode, like the XJ12? Early on I thought there might be a problem with the trans! But I learned it is the norm, as designed. However it will kick in first gear if it gets full (or a lot of) throttle input even when in Normal. In Sport mode it always starts off in first. Under casual acceleration, the lack of a 1-2 upshift makes for even smoother running in city traffic. I love that.

 

No, the XJR has a first-gear-start in both "N" and "S" modes.

Interestingly (well, to me, anyway) is that the service manual makes no mention of this. I have to wonder if Jaguar originally intended the same second-gear-start as the XJ12s but changed their minds due to the sportier nature of the XJR (?).

Or...just an oversight in service manual editing.

Cheers
DD