When low temperatures will not select drive

[rjhemming873]

Normally the gearbox selectors on the "J" gate have worked perfectly, however during the winter of 2021, 2022 and now 2023 the J gate will not select drive or any of the left side gears when the temperature outside falls below freezing. The gearbox oil and filter have been renewed to try to sort out the problem but it has not worked. To get over the problem I sit in the car and select reverse which works and move the J gate through all positions and after about 4 to 5 minutes the gears work normally. This problem only ever occurs during sub zero temperatures. I have adjusted the cable under the J gate on several occasions but this does not cure this fault.
Any help or guidance on this would be very gratefully received.
I normally do all the maintenance on the car myself but this problem has baffled me, thanks for any help
Richard Hemming

[JimMann]

Hi Richard, always helps with seeking a solution if folks know which model you are experiencing the problem in.

Currently, it sounds like you have something freezing up in the lower temperatures, but there is not really anything in the mechanism that should be susceptible to freezing, unless you have incorrect grease in the mechanism.

Jim

[Astromorg]

I've never heard of this happening, but is there a possibility that the Bowden cable of the selector system has got water penetration somehow? Hence the problem with temperatures below zero?

[rjhemming873]

Hi Again, Sorry, should have mentioned the car. It is a 2003 XK8, VIN132A34782

[mike020150]

On first sight, this does appear to be an odd problem. Looking for clues in your post, it sounds as if either the selector mechanism isn't travelling far enough or there's a lack of pressure within the gearbox. Adjustment usually cures the first set of issues providing the cable isn't damaged and wear in the lever pivots isn't excessive. For a lack of pressure inside the gearbox, it pays to consider simple things first. Has the gearbox ever leaked any fluid whatsoever? If so, the leakage source(s) have to be corrected. It is very difficult and very messy to refill these gearboxes properly and they are highly sensitive to the fluid level. Even garages often get it wrong, so checking that the level is correct is vital. Naturally in winter, the oil level will be lower when it's cold, making the correct oil level even more critical. If it's too low, there will be cavitation and resultant low oil pressure until the oil has warmed slightly and expanded to reach the minimum level for correct gearbox operation. Hence, it's important to check the oil level the official Jaguar way:

From stone cold;
"The vehicle must be on a horizontal ramp.
The parking brake must be applied.
The engine must be running for 2 minutes with the transmission selector lever in the "P" position.
With the engine running and the foot brake applied, circulate the transmission fluid by:
Moving the transmission selector lever to the "R" position
Waiting for three seconds.
Moving the transmission selector lever to the "D" position
Waiting for three seconds.
Moving the transmission selector lever to the "P" position."
If no oil emerges when the filler plug is removed with the engine still running, add oil in 0.5 litre increments until it runs out of the filler hole.

This whole process has to be done quickly with the transmission oil cold (preferably below 30 degs C and certainly no higher than 50 degs C). Filling a gearbox and then leaving it overnight to cool before checking it again in the morning is a good practice to follow. If the transmission has been filled correctly, a lack of initial oil pressure could also be due to a faulty internal valve but why only in winter would be less easy to work out! Mike.

[rjhemming873]

Hello Mike, Many thanks for your very helpful reply. I will take it to the garage I normally use for things I can't do and see if they can have a go at the way you suggest. I have been there when the gearbox was filled and nothing like you have suggested was done.
Thanks again
Richard

[darryl1959371]

Hello,
I have this Symptom on a Different Make of Car which Automatically Registers the Temperature of the Auto Gear Oil and just Often Changes Up and Down when Driving to Heat The Gear Oil for a Few Miles After Initially Driving Off...!!
I Overcome this ' Stationary Problem ' During Long Term Parking by Parking the Auto Gearbox in Neutral..Hand Brake.. ALWAYS OFF with WHEELS CHOCKED . Car Moves directly on Start-Up but Gear Changes a Bit Slow Until Oil Warms Up ....Just avoid any ' Le Mans Start...!!!
Hope This Helps,
Best Regards,
Darryl

[MarkX]

To Mike's very good post on the procedure its probably also worth adding that David Marks a the recent XK8 Seminar said that when he refills a customers gearbox he will leave it overnight as the oil will settle and in the morning often more can be added.

Good luck


Mark