Auto transmission problems
My GTO (non-turbo auto) has some odd auto box problems. Despite being a 1993 car, it has only done 35,000 miles. It spent some years being parked up and not used. I've read the troubleshooting guide in the manual, but some of these don't fit the symptoms listed.
The symptoms are:
- Occasional hard shift between first and second (doesn't matter if I'm accelerating hard or not)
- When kicking down at about 60mph, unless I put my foot down hard, it will sometimes shift between third and fourth very quickly and very hard until it either chooses a gear, or more likely, I let off and let it drop back into fourth.
- When braking to a halt, the box will hold on to a gear until it almost stalls, when it will let go with a "clunk" that can be felt but not heard.
- Occasionally, when shifting from Drive to Reverse, or Reverse to Drive, a hard clunk can be felt, like a clutch has suddenly engaged. Nothing can be heard.
Most of the time, the box is fine; there are no heavy gear changes, and if I'm accelerating gently, it will shift through the gears with smooth changes. I think it's due a fluid change as the fluid (which I presume used to be red) is now a little more brown.
The car was bought as "spares/repairs" with almost no service history, so I very much doubt it's ever had its fluid changed. On the basis of that, and the colour of the fluid that's in it, will I do more harm than good if I fully drain the box and put fresh SP3 in with a new filter?
The car was also parked up for some time (I don't know how long, I suspect a couple of years) and due to the lack of history, it's getting a full service. Is it possible these problems are just down to a lack of use and fluids getting old?
Appreciate any advice.