I have a 2002 VDP with 182K on the clock. On a local drive today I was stopped by a traffic light. When I released the brakes at green the car remained stationary, as if in park. The car would not move on initial application of the throttle and then lurched forward after a second or two. I turned around and headed home with the gearbox shifting up and down normally. The behavior repeated itself at another traffic light and I shifted the box into neutral. The car rolled a little as would be expected. The remainder of the trip home was uneventful and no "transmission fault" message appeared. I changed the ATF around 60K miles ago using the recommended ZF fluid. There are no leaks.

The symptoms don't sound like a A drum issue. Valve Body?

 

From your initial description I would suspect a locked brake caliper. But you said she rolled on the next sign of the issue. Did she rev and then plunge into gear? If so, I then would suspect the dreaded A drum.

Is yours a base VDP or SC VDP? Only the base is susceptible to this issue.

 

Did you also change the gearbox filter? If not, you can try with a new filter. If no improvement, it is possible that the valve body has developed a crack (not uncommon on these ZF gearboxes). For detailed inspection, you would have to remove the valve body. If there is a crack, it can sometimes be repaired (welded).

 

The infamous A drum is in the process of breaking in the transmission. As the crack grows on the drum, the worse it’ll get. It’ll feel like you got rear ended taking off from a complete stop.

 

I agree w/ the A-drum consensus.

 

This is a defacto worn valve block symptom - the valve wears a groove/lip in the wall of the valve block and sticks, this leads to over pressurized valve and a bang or lurch shift...

You can save the trans if the shifts have not been heavy enough to a) break the circlip holding the A drum onto the shaft or b) valve body cracked. Both of these items if failed will need a trans out rebuild. If both are OK then fitting a TransGo kit will keep the car running.

If it still shifts, then order the kit remove the valve block assembly and offending valve, replace with the one from transgo and perform a trans service. If it just makes funny noises then it's rebuild or recon.

 

I'll second Sean's analysis.
I swapped in a Transgo shift valve in my 1998 VDP last week. Mine was shifting out of gear at stoplights too.

Changing the shift valve seems to have fixed my issues, the drivability is far improved. If you are able to do so, I'd stop driving it until you can get the shift valve installed, one bang-shift too hard can break the A drum. The valve is pretty inexpensive, it will take a few hours to swap it out, but its worth it.

 

The issue had appeared on a cross country trip after a pit stop two weeks ago and it did it once. At the time I thought the same thing - sticking brake caliper. Since this car has a late 2001 build date I figured it already had the uprated A drum (it's a base VDP).

I figured it was either the A drum or the valve body. Rebuilding an automatic is no big deal for me but I need to decide now if I have the desire. I also have a growling hub bearing and a few other issues - some minor - but I'm getting the gut feeling this car is trying to become a hangar queen. In it's defense it has been an every day work hack over nine years and 100K hard miles.

Sorry for the slight rant. My wife can use my '85 SIII in the meantime so I'm not under undue pressure to decide my course of action.

 

Recent member posting on this same description by the OP.... https://www.jaguarforums.com/forum/x...uccess-217445/