This old 4.2 V8 auto (actually an S6 Station wagon) used to shift into top on the 4 speed trans at quite low speeds, and I would often shift into 3rd around town, and became quite aware of how it shifted.

Now, the shifts are slightly different, and it won't go into top. It also made a nasty jerk going from reverse to drive. It is normally so smooth doing that.

Any ideas please? I can't see a trans dipstick anywhere!

 

Any indicator light on the dash showing? Any trouble codes?

 

No lights showing. Everything seems normal otherwise. I have also noticed that cruise control doesn't work now. I think this is possibly related somehow.

I am wondering if there is some micro-switch on the gear selector, perhaps on the 3rd gear gate, that is stuck?

 

I have noticed a few other odd things. The car is actually stuck in 3rd gear all the time. It never shifts at all. Also, the interior light is behaving strangely. With the engine running before closing a door would make the light go off almost immediately. Now there is a long delay of several seconds after pulling off before it goes out.

To reset the computers, I disconnected both batteries for an hour. For some reason this car has one battery in the boot/trunk, left side, and the big one under the back seat. Once reconnected I then left the ignition turned on, in the running position (but engine off), for 10 minutes.

Still no difference.

 

*** FIXED ***

The problem was fuse 14! This contriols the reversing lights, diff, and Auto box.
A spot of cold weather, I noticed the heated seats were dead, so I re-checked all the fuses.