In warmer temps (60+ F) the J gate works perfectly. When it is cold, especially sub-40F inside the car, the shifter gets very stiff and hard to move from P to D - the pressure applied feels like you are going to break the plastic bezel around the shifter-rod, and when you do move it to D the D-indicator does not light up and the car drives odd, like it is stuck in the wrong gear (feels like 1st gear maybe?), simply moving the Jgate to 3 (passing 4) and returning to drive makes the D indicator light up and the car drives perfectly.

Sometimes shifting back into P the indicator for P does not light up without gently jiggling the shifter so it seats into the P-position (never experimented with leaving it in P without the P-indicator actually on.)

Once the heat is running and the interior temp warms up, the Jgate returns to perfect functioning.

Sport mode makes no noticeable difference - I leave it off, so it should not even be able to enter 1st gear...

The previous owner of my car had spilled a huge amount of cola into the jgate, leaving a gooey mess in there but everything had worked fine for the prior 4-winters. I've previously removed the shifter-bezel and little-by-little sprayed an entire liter of windex/window-cleaner onto the circular discs that are visible through the shifter-slot - that dissolved the cola and then evaporated leaving the discs looking perfectly clean, I'm guessing wherever the liquefied-dried-cola-remains leaked down into is now causing this problem - but it could also be unrelated and a shifter-cable linkage issue?

What should I try next?

 

Sounds like gunk build up, different lubes act differently in different weather ...(and no I won't say that 3 times fast). The bezel comes off quite easily...remove shifter knob, lift straight up on the bezel trim, remove the 4 (I think 8mm bolts) trim ring and your there. Start probing around for any excess build up (perhaps some Coca-Cola or simply oooold grease mixed with Coke. The Coke may have taken some time to pick up a enough grime to cause this.
If you find it is clumped grime, I would spray it down and clean everything I could reach with regular WD40. Get the flex nozzle to get into cracks and such and blast off what you can. Then get a can of lithium grease (here's the WD40 brand, White Lithium Grease Spray & Lubricant - WD-40 Specialist) and lightly spray those same areas. Regular WD40 is good for cleaning stuff, but it is mislabeled as a lubricant, ...and white lithium is good down to '0' with direct exposure. Be sure to put some towels around the spray areas so your not cleaning any back spray or blowout. Perhaps using a zip lock or similar heavy walled bag over the spray tip, coming in from a sealed corner and taping it in place, will also help knock down the spray and save clean up.

 

I could shoot some wd40 in there, but if the cola is trapped inside I'd think it won't remedy much more than the window cleaner - is there an opening at the bottom of the shifter assembly for the liquid to escape?

 

WD40 will break down the build up then dry off, the pressure from the nozzle will knock out the gunk, thus the zip lock type bag to knock down the spray/splatter.
....or if your into a safer environment, use Simple Green, it will have to sit because they don't have aerosol, ....but you'll still need the lithium.

 

Would simply green be better than window cleaner?

WD stinks so it is not my first choice of remedies and spraying out the contents into the vehicle interior is more cleanup than I'm ready for. It's quite likely that the bag trick won't catch everything...

Anyone have a photo of what is underneath the jgate at the bottom or other photos of how the jgate is assembled mechanically? My question is if it is safe to just spray simply green (or more window cleaner) and then leave the build up down there below the jgate mechanics or is that what is likely causing the stiffness.

 

The window cleaner will create rust because it is alcohol based and it will clean off any lubrication you have on your linkage.
This should give you a better idea of the unit.....you can pull it all apart, don't be afraid of it, just take your time....and clean as you go.

 

...and here's one taken down a bit more...

 

Thank you!

Does the mechanical linkage go beyond what's in the photo (like a direct or via cable connection to the transmission?) or is this a by wire electronic/solenoid system?

Would simply green cause rust like the window cleaner?

 

The simple green isn't as harsh as the window cleaner, but I would still shoot some white lithium in there.
Its electronic, that's why breaking it down to clean it isn't a chore:

 

Mechanical linkage to the transmission is accomplished by a cable connected to the right-hand side of the J-gate (that small black knob visible in highhorse's first picture above). If you disassemble the J-gate for cleaning, you have access to the adjusting nuts, and it would be worthwhile to also make sure this cable is adjusted properly. My cable had stretched over the years, resulting in similar symptoms to yours (not going into gear when put in "D", having to shift into lower gears to get the car to move forward, the "D" position then working once the transmission warmed up a bit).

 

Very interesting, how would you adjust the cable? Presumably, I'd need to take up slack from stretching - my jag has 135k+ miles...

 

Disconnect the two locking nuts on the side of the J-gate, ensure that the J-gate shifter and shift lever on the transmission itself are both in the neutral position, then tighten the locking nuts back down.

A word of warning, the connection of the transmission cable to the transmission lever might be corroded. Mine was, and I broke the threaded stud that connects the cable to the lever, necessitating the purchase of a used cable to replace the existing one. Disconnecting the cable at this transmission end (step 8-1 in the instructions above) isn't really necessary if all you're doing is adjusting the existing cable. Just make absolutely sure that both the shifter and the transmission lever are in the neutral positions before you tighten the cable locking nuts down and you should be good.

Also, when you loosen the locking nuts (step 6 above) make sure they're then finger-adjusted all the way out to the end of their threaded travel. This will ensure that the cable can move freely at this end when you're adjusting the transmission lever to the neutral position underneath the car (step 8-2).

 

Also, this: "the car drives odd, like it is stuck in the wrong gear (feels like 1st gear maybe?)" sounds like how my transmission was behaving prior to adjusting the cable.

Shifting down to "4" would get the car to move forward, but the car would not shift out of first gear for a mile or so until the transmission had warmed up. It also had problems when accelerating from a stop, with the engine revving a bit before the transmission would then "slam" into first gear. These problems would all go away when the transmission had warmed up, when it could be put back in "D" and then driven completely normally. All these cold temp problems completely disappeared once the cable was readjusted.

 

Thank you!

 

Okay, so I've procrastinated half a year and now I need to fix this, lol, but when I went to tighten the cable next to the j gate, it appears really tight in the gap to access the nut to take up the cable slack - what tool are you supposed to use to adjust the nut that can fit in there?

 

I took out the whole center console to access these nuts. Since I also had to replace the entire cable, there was no other way of doing it.







Kind of a pain, but the adjustment nuts are easy to access after the console is removed.

 

I've removed the console when I first got the car to fix a loose connection to the cigar lighter, it was an ordeal that seems unnecessary - isn't there some tool that can get in there through the crevice above?

 

Picked up a wrench kit that has skinny shafts, hoping that will get in there - to be continued...