I have an 04 S-type with 4.2
randomly it will seem to disengage then reengage.
as if it lost Hydraulic pressure for a second or two.
it is consistent. Does not appear to be a hard failure
Not a slipping clutch I know the difference.
its an all or nothing type thing like an on/off switch

transmission cooling lines? momentary loss of hydraulic pressure?
yes im grasping...

any advice would be helpful as for replacing the transmission would exceed X2
the value of the motorcar

jsnider1970@yahoo.com

 

Low on fluid / loose trans bolts / see the many posts about those.

 

You could try checking for codes ,
Checking the trans fluid level , (easier said than done) , rebooting the car .
. I think I would even be doing a fluid and filter change and trans software update before just throwing another trans in it . or rebuilding the old one .

 

More info, please

How many miles? Have you been seeing any spots on the ground? Have you been under it, removed the belly pan, and looked for evidence of leaks, any codes, etc.?

First thing I would do is to change the fluid, pan, filter (all happens at once with a trans service kit).

==================================================
Jaguar: Grace, Pace, and Space - Sir William Lyons
2015 JCNA National Slalom Champion Class M
Current: '08 Jaguar S-Type 4.2 "Satin Edition" (250.06 whp / 259.67 torque)
Past: '05 X-Type 3.0/auto Jaguar Racing Green

 

First things first - tighten the two shifter cable attachment bolts on the side of the ZF transmission pan underneath the car. They are known to come loose and fall off, stranding the car wherever it happens to be at the time. Those two 8mm bolts should be snugged up every time you have the car up on jack stands for routine service. It takes about 30 seconds and is well worth the time and effort to do so....

 

>First things first - tighten the two shifter cable attachment bolts on the side of the ZF transmission pan underneath the car.

Yes!!!!

================================================
Jaguar - it's not an automobile, it's a Motorcar
2015 JCNA National Slalom Champion Class M
Current: '08 S-Type 4.2 "Satin Edition" (250.06 whp / 259.67 torque)
Past: '05 X-Type 3.0/auto Jaguar Racing Green

 

reboot the car? replacing filter and fluid is a bout 200
trying not to spend if not going to resolve..

 

its an 2004 with 106k no codes have a guy with a snap-on computer if i can limp it over there.. tried overfilling transmission a bit... seemed to help temporally.

better description would be as if trans goes in to neutral for a second then back into gear
regardless of where shifter is it can happen at any time when car is in drive,1 or 2

i will have time this weekend to get under it..

 

At 106K miles it's been living on borrowed time if that's the original fluid.