Greetings
I have a great 91' 740
with 250,000 kilometers
1 any thoughts on Lucas oil stabilizer, will it do any good?

2 my last muffler the last one in the car, will need to be replaced soon
any thoughts any brands to avoid, any great ones?

3 I plan to get the valves adjusted, also debating on the timing belt, @ 250k, I know it wouldn't hurt to have it changed, I bought it with 240k and not sure when it was last changed, the question is, is there any correlation, I think, think and think, but am not surewill one have any effect on the other,
can I get the valves done, and then change the belt at a later date????

4 it is strange, automatic/the tranny seems to have a mind of its own
when I drive agressively it changes fairly smooth
if I use a soft foot it seems to shift quite rough, is this normal?????
is it possible to change shft points
at times it shifts smoothly, sometimes it shifts quite roughly

thanks so much for any pointers you may have for me

First and foremost, you should read through as much of the FAQ as possible - except the very complex parts. These are good questions though
My 90 had its valves done and I'll be having my mechanic change my T-belt and rear cam seal and disty cap (while he's in there) in a couple months.
I would change the belt when you can - UNLESS you have a particular engine (interference), which was not sold in the US AFAIK, your belt breaking ****should**** not damage your engine. There are several versions of the B230 engine, there's a list in the FAQ ..somewhere. Sorry I can't point you. I know the B230F engine (not the block, but engine) is not interference and ours broke on use a few years ago (parents didn't keep it up and I was 13). The fix was to just change the belt.

As far as the tranny, I suppose you mean the AW7x Automatic? I have only had one volvo (first car actually) and it can shift roughly and smoothly. I recommend changing the trans fluid and filter. To smoothe my shifts, I gently and slightly lift my foot from the gas pedal. You can mess with shift points with your foot, but for permanent changes, you can adjust your kickdown cable.
There is a cable attached to the throttle spool that directly affects the shifts. The more tightly the cable is pulled, the higher rpms before a shift (and too tight will definitely cause driveability problems).

Low fluid has caused problems for me - I had to use the trans with the radiator lines disconnected and washed the AC condenser with about a quart of trans fluid. (I was not about ot reconnect the lines to back up 4 feet) I added what I thought I had ejected and noticed rough shifting. I was towards the low side of full and added some - this made a major difference for me. If you want to see what a huge difference the kickdown makes, try disconnecting it from the spool for a mile and drive up to 40 mph. It also influences (other factors like road slope do too) how far you can open the throttle without downshifting.

Best of luck, Welcome to the community!
-Will (half-noob)
--
1990 740 Turbo, on its way to stock specs, maybe beyond

The FAQ is a great place.
Get there from the picklist at top right of these pages.
Once there, scroll down to see the table of contents.

Auto Tranny section has a section on adjusting the kickdown cable.
That section is very informative; before reading it I incorrectly adjusted the cable to shift earlier which was not a good idea.

I'd do a transmission fluid flush per the FAQ procedure. No need to drop the tranny pan or mess with a filter/screen.

I'd also change the power steering fluid, because changing out a dead steering rack is very expensive. Don't change the fluid by disconnecting a hose to run into a container. I tried that, it drains way too fast. Use a turkey baster to empty the reservoir, then refill. Then idle the motor and work the steering wheel. Shut down, empty the reservoir again and refill. Do it 5 times and you'll have about 98-99% new fluid in the system. You'll need 2 qt. fluid.

Valve adjustment:
We've had 5 240s with red block 4-cyl motors and never had any valves adjusted. My first tech said they rarely go out of adjust. Something about self-compensating wear and quality steel. I don't know if he was right or not, but over the years we've had at least three very good brick-specialist mechanics and none has ever recommended adjusting the valves. I don't think I hear any valve clatter, either. I'm talking a total of maybe 500-600K miles driven.
--
DAMHIK: Don't Ask Me How I Know - - - Sven: '89 245, IPD sways, electric rad. fan conversion, e-codes, 28+ mpg - auto tranny. 500 mi/week commute. '89 245 #2 (wifemobile). '90 244 (spare, runs).

FYI - The 16 valve (interference) enfine was sold in the U.S. Quite a few of them as a matter fact.
--
Chris - 1990 740, 1973 1800ES (Non-running), 1993 Dodge Dakota (Still has a little paint left on it)

DOH!! I completely forgot about the 16 valve. That would be a nightmare of bent valves in case of timing belt breakage. I was thinking of only the B230's.
-Will
--
1990 740 Turbo, on its way to stock specs, maybe beyond

Timing belt and valve adjustment are completely independent of each other. While they rarely go out of adjustment, it might be worth checking them. This is relatively easy compared to actually making any adjustments.

When you do the timing belt you should also replace the three oil seals (cam, front crankshaft and idler shaft) and probably the belt tensioner too, if it is at all suspect. Might as well do the V belts too (unless they look recent) since they have to come off to change the T belt.