Auto Gearbox Advice

[StanC]

My 1996 960 3Ltr 24v has the AW 30-43 automatic gearbox. The car has done 176,000 miles and I have always ensured that the ATF has been changed every 30k miles, using the specified genuine Volvo transmission oil.

Over the past 2-3 years the gearbox has begun to develop a faint whine - this has been audible only when cold and has disappeared when the 'box warms up. But just recently the whine has become more noticeable (to me - my other half can't hear it) and is audible very faintly now even when the 'box is hot. The 'box is working fine, with nice smooth changes and the ATF looks clean on the dipstick.

Automatic gearboxes is something I haven't had any experience of working on. Does anyone have any experience of this gearbox - do I need to be worried about the developing whine and is there anything I should do to stop it getting worse?

Thanks in advance,

Stan.

[Laird Scooby]

Sounds like one of two things, possibly both to me.

First is proshaft centre bearing, second is gearbox extension housing output shaft bush and seal. Usually those two go hand-in-hand, when one starts to wear it makes the other wear.

Determine which it is and fix it sooner, rather than later or just do both to be on the safe side.

Also consider changing the fluid in the box to Carlube ATF-U, do several part-changes rather than the flushing/gibbon/ape method as it's more gentle on the box introducing the thicker, fresh fluid that way.
The Carlube stuff is very good at cleaning boxes and reviving old oil seals, better than the standard Volvo stuff which in effect is Dexron II-D.

Space the part-changes out to one a month for 3-4 months, depending how clean it is after the 3rd change. You can either do a "sump-dump" or use a 12v oil extraction pump that can be bought on ebay for £15 ish.

You'll notice the difference in how smooth the box is on the ATF-U and maybe even your other half will feel the difference. Should also notice an improvement in economy too, especially if you add 0.5L of ATF-U to the engine oil as well.

Yes, you read that right. It cleans and frees the hydraulic tappets, rest of the engine and revives the oil seals too. Can also help sticky piston rings too.