Does it damage an auto 'box to use it 'manually'?

[Del]

My Ford A4LD 'box drops out of top occasionally, with a rebuild apparently required to cure the problem.
I was wondering if I would damage it less if I made more use of the 3-2-1 options rather than just keeping it D for everything, with the attendant annoyance of it slipping, my theory being that if it slips, it's causing damage.
I'm doing a lot of urban town driving at the moment, so it doesn't even get *into* fourth very often but I don't really want to cause *more* damage to other parts of the 'box.
Does that make sense?

[welshpug]

does it actually drop out of gear or just change down to 3rd?

bunging it into 3 just means it shifts as normal from 1-3 instead of going to 4th, its not a manual shift.

[Del]

No, it drops out. With cruise control on, on a level road, it will drop a gear, revs increase but road speed doesn't.
I know 3 in effect locks out top, but I was also wondering about using 3 - 2 - 1 as 'manual' gears, shifting up from 1 to 2 and 2 to 3 (and vice-versa) as required.

[composimmonite]

Manually shifting an auto does no harm at all. In fact if you read some of the older cars owners manuals it tells you how to do it for best economy / performance.
However double check the oil level is correct in your vehicle. Confirm how to do this as some of the cars I've had it stipulated autobox oil level has to be checked when engine running as checking when engine switched off give false reading. Also check oil (wipe on clean white tissue) to see if any contaminates from burnt clutch lining etc.

[kenb]

I tell you what that may be as my old 94 Granada 2.9i had the same problem. It was the speedo sensor assuming yours is leccy like mine was on the gearbox. Mine kept dropping out of 4th until it didn't switch into 4th at all. I put the query on the Granada forum at the time and every reply said speedo sensor. So bought a new one and it was sorted. Guess it was a common problem.