Is it time for a new automatic gearbox ?

[vtl]

If I remember correctly, there are 3 final drive ratios available in AW55: XC70 AWD is lowest, then "regular" and T5 is highest. I drive a FWD AW55 in XC70, had to swap my differential.

But read the codes first?

My controlsystem is "brand new" replaced is not even a year ago

Could be a loose valve body connector. Need to remove the valve body cover and inspect the connectors.

[greffel]

No fault code in Vida.
When I changed the valve body I had to change the valve body harness a couple of months later due to bad connection.
The harness problem triggered a Vida code.

Just spoke with the local Volvo dealer and they said with 99% certainty that the gearbox i slipping due to bad/burnt clutches =(

I have found a "R" gearbox model year 2004 with only 15000km on it for a good price. So the question ...will it fit and work correctly.
The Volvo dealer could not say, they only recommended to get a rebuilt one with warranty

[vtl]

You said ATF looks good? Burnt clutches would result in a very dirty/sooty ATF, like that:







Plus the speed sensors would attract a lot of steel. Here my poorly rebuilt transmission was slipping only for 5 kms:

[vtl]

I have found a "R" gearbox model year 2004 with only 15000km on it for a good price. So the question ...will it fit and work correctly.
The Volvo dealer could not say, they only recommended to get a rebuilt one with warranty

Don't think the final drive ratios are the same. You may need to split both transmissions, unbolt the oil pumps and swap differentials.

[firstv70volvo]

No fault code in Vida.
When I changed the valve body I had to change the valve body harness a couple of months later due to bad connection.
The harness problem triggered a Vida code.

Just spoke with the local Volvo dealer and they said with 99% certainty that the gearbox i slipping due to bad/burnt clutches =(

I have found a "R" gearbox model year 2004 with only 15000km on it for a good price. So the question ...will it fit and work correctly.
The Volvo dealer could not say, they only recommended to get a rebuilt one with warranty

From what you've described, where you hear and feel nothing when engaging either D or R this doesn't sound like a slipping clutch it sounds like absolutely no fluid pressure being applied to one or more of the clutches and why I suspected a clogged filter. If you don't hear wining from the transmission pump being starved of fluid though there may be another problem other than a clogged filter. At this point it would be a good ideas to look at some of the pressures with a gauge. There are multiple tap points available for pressure checks and with your symptoms it might be best to start with the forward clutch C1 and 1/2 reverse B5 pressures checks. It would beneficial to know if there's no pressure at one or both of these clutches when checking in D. The B5 clutch is applied for both D(first 2 gears) and R so most interested in the pressure to this clutch. If you have a geartronic shifter you could try manually selecting 3rd gear when your transmission is not acting up and not engaging D or R to see if will engage 3rd gear manually. This would help determine if there was a problem with the B5 apply, does 3rd gear does engage in manual 3rd or not.
I think you should really to try to rule out any problem with the valve body and solenoid control before changing the entire transmission out. It may be there are bad clutches or other internal problems with the transmission but from your symptoms it's worth checking out some other things first. You did have problems with the wiring harness once so it's possible there may still be a problem with the wiring.

Also, it's my understanding if there's badly slipping clutches you'll get a gear ratio code set and or really nasty fluid as Vtl has shown.

[greffel]

Status of the oil:

This sensor threw a ECM-5200 at me last week, but looks clean:

This sensor makes me a little bit more worried.

Magnet pen down the sensor hole.....

[vtl]

Is it input sensor? There's another one, located approximately behind ABS unit.

[vtl]

Magnet pen down the sensor hole.....
20211011_183656.jpg

Ok, that is convincing. The transmission saw low oil pressure. Now, why did it happen? Is it a clogged filter or loose valve body connectors?

Unfortunately, the valve body got a piece of this soot.

[greffel]

Sensor position:

[vtl]

Yes, that's input sensor. Look for a similar sensor, closer to firewall.