Aw55-50 sn valve body "B" with solenoids slots up! Topic is solved

[bluebenzin]

Hello,
I have an AW55-50sn in my car, year is 2001, valve body is "B" but the solenoids are up. I couldn't find this configuration in documentation in MVS.
My question can I replace my valve body with any model? Or should I replace it by early model?
Thank you.

Valve body

IMG_20220301_103029.jpg (3.17 MiB) Viewed 4299 times

[firstv70volvo]

Hello,
I have an AW55-50sn in my car, year is 2001, valve body is "B" but the solenoids are up. I couldn't find this configuration in documentation in MVS.
My question can I replace my valve body with any model? Or should I replace it by early model?
Thank you.
IMG_20220301_103029.jpg

According to the ATSG manual it's recommended practice to use the later revision C stamped valve body to replace earlier revision valve body; No ID, A or B stamped VBs. I can confirm with my 2001 V70, which originally has a No ID or A valve body and later a C stamped (dealer installed replacement transmission) and then a replacement B stamped valve body (I replaced the C valve body due to shift problems after 30K miles) in it and all these valve body revisions worked. The current B stamped valve body in my car is actually a GM AC Delco replacement part (made by AW), which can be used in a Volvo with a couple of changes. The B stamped valve body has been in my car for 45K miles now and works great. The AC Delco 24228787 valve body can be purchased new from several sources for ~$500 to $700, Rockauto and Amazon have the lowest price. A good quality rebuilt VB will also be in this price range so avoid the $150 "remanufactured" ones.

The photo you posted with the linear solenoid connectors in the up position on a B stamped valve are not the original solenoids, someone replaced those solenoids with earlier version solenoids. From the looks of the wiring harness it looks like there's enough wire length to use bottom position solenoids so you won't have to replace the wiring harness or lengthen the wires with the later revision VB/solenoids.

Here are my notes on how to use the AC Delco part in a Volvo.

AC Delco VB to Volvo Install Notes and Photos.pdf

(816.89 KiB) Downloaded 288 times

If you buy a used Volvo valve body (no matter which revision) you should check for the B5 control valve spring and matched the original valve body configuration, which is likely no B5 spring configuration.

[bluebenzin]

Thank you very much for the quick and long reply,
Now its clear for me.
I'm planning to replace the valve body with later version And I hope to fix my gearbox which symptoms are:
1-Gearbox fall in limp mode just after starting the
engine when (cold) and very harsh revers
2- gearbox dont fall in limp mode after around
around 30 minutes when fluid as warm but still
there harsh up shifts and down shifts specially
from 2 to 3 and 3 to 2 (not bad as when car is
cold)
3- checked s1 value is 17,4ohms (out of range)

Do you think changing valve body will fix every thing, or should I change the whole gearbox?

I found some chevrolet captiva gearbox around 500$ with warranty, Do you recommend this option than changing only valve body?

Thank you gain

[firstv70volvo]

Thank you very much for the quick and long reply,
Now its clear for me.
I'm planning to replace the valve body with later version And I hope to fix my gearbox which symptoms are:
1-Gearbox fall in limp mode just after starting the
engine when (cold) and very harsh revers
2- gearbox dont fall in limp mode after around
around 30 minutes when fluid as warm but still
there harsh up shifts and down shifts specially
from 2 to 3 and 3 to 2 (not bad as when car is
cold)
3- checked s1 value is 17,4ohms (out of range)

Do you think changing valve body will fix every thing, or should I change the whole gearbox?

I found some chevrolet captiva gearbox around 500$ with warranty, Do you recommend this option than changing only valve body?

Thank you gain

Because your transmission is going into limp home mode I'm less certain just changing the valve body will be enough to fix everything. Limp home mode usually means there's enough slippage withing the transmission to set this mode, either from a clogged filter and too little internal pressure or badly worn friction plates. Do you hear any whining type sound coming from the transmission, especially when cold?
I don't think the Chevy Captiva gearbox will work in your car even if you were to make changes to the valve body to make it compatible with a 'Volvo. The Captiva will have a different wiring harness connectors, and I don't know if the differential axle splines or axle diameter and seals are the same or the final drive ratio, which you'll need to match.

From what I found out is there's at least three final drive ratios 2.27, 2.44 and 2.65 with the Volvo AW55-50SN/51SN transmissions and if your 2001 is a FWD T5 2.3L Turbo like my car the final drive ratio will be 2.44. If you're looking at used transmissions you'll need to match the final drive ration, AWD/FWD config and wiring harness connectors. I believe in 2005 the wiring connectors changed. From my experience it's not easy finding a compatible used transmission if you're looking at different Volvo models(with same 5 speed auto trans) and different model years. Also, when looking for earlier model years used transmission like 2001s there's not as many low mileage good used ones out there. Some people have done additional work with used transmissions to make them compatible like swapping out the ring(or differential) and pinion gears between the original and replacement transmission to get the correct final drive ratio. This requires opening up the used transmission though so more work.
If you have the money and the rest of the car is in good shape it might be best to rebuild the transmission or purchase a remanufactured one from Volvo but there are expensive.

[SuperHerman]

Lets back up - what has been the service history of your transmission? What has been the condition of the transmission oil?

Thinking back on my old 2001 XC70 it had a no mark VB. I replaced it with a A which I assembled incorrectly, so I reinstalled the No Mark that I had also rebuilt with the Trans Go kit. After that all problems went away.

The AW55 has a solid history and is a good transmission. The early ones had solenoid issues. But there are ample posts where the filter does clog up due to wear and the internal filter getting clogged up. The transmission oil color will provide a solid clue.

[bluebenzin]

Thank you guys for replay

@ firstv70volvo it's going to limp mode and harsh
revers when the car is cold, when the fluid of the
tranny is hot things going to be better (Looks like
a pressure issue)
I don't hear whining. Captiva tranny will be used to
rebuild mine using valve body and some plates
and clutchs (just the internal parts)

@superHerman I changed oil just one time using 3.5
litters liqui moly with Jws 3309. But nothing
changed I'planing to do 2 more oil changes. The
color is not red like new oil. The
first owner of the car told me he changed oil
using DexIII so now it's 50/50 DexIII and jws3309
The owner told me that plates are like new no
wear traces on them. He didn't have service
history too.

My car is Laguna II I came here because MVS is the best source that I found full of information about AW55-50sn. I didn't find expert people in french forums about this transmission. And Sorry, I don't speak English very well.

[SuperHerman]

Your English is perfectly understandable.

I don't know what is available in Algeria, but you can use Toyota Type IV. I have used it and is is perfectly acceptable (suppose to be the same stuff). I have also used Valvoline MaxLife. For now just use the cheapest stuff that is 3309 (Volvo) compliant. Dexron III is not a good fluid from what I have read for the AW55.

What you need to figure out is whether your problems are the valve body, transmission or more specific the transmission oil filter (which is a mesh screen that requires transmission tear down to properly service. Some have drilled holes in the screen (read up on it) and then put an in-line hose filter to replace it). Usually you will not get the operation you are getting and the transmission will whine shortly after start up. As the filter is clogged the transmission does not get oil and it starts to whine. As the vehicle drives it gets worse, not better. The car usually does not move at all. By knowing how the fluid looked originally, it was really black and thick, is a hint as to whether the filter is clogged up. If it was just black but proper thickness then the problem is most likely in a failed solenoid. If it had questionable traces of metal - stop and look at transmission.

What happens in the early versions of the valve body solenoids is they start to build up crud, like plaque on your teeth. Then they don't move correctly and they open and close properly, needing force from oil pressure rather than smooth as designed - hence the slamming. If they are completely stuck they can burn up and/or not open at all.

If it were me I would not buy a new valve body, but remove the solenoids and repair or replace them. There are specialty tools that will open the case and allow one to clean up the solenoid and then re-crimp them. Here one buys the Trans-Go kit and cuts the end off and cleans them - then reseals them with a cap that comes in the kit. You can pull up some videos on this process. A machine shop would be able to make the caps. I don't know what is available in Algeria, but I assume the people there are creative and resourceful. You can also do some cross checking and replace the solenoids with those from GM, Nissan, ... if they are a match. Here Rostra makes replacements, maybe you can source them there.

So do some more diagnosis to eliminate a clogged filter. A shop should be able to put a pressure test on the unit to see if you are getting good pressure, if you are then the filter most likely can be eliminated.

Wrapping up, if the problem is the solenoids (you mention one has a high ohm reading) and not the transmission/filter I would focus on the solenoids only. Rebuild or replace. Drain your fluid and reuse it, but replace as much as you can with 3309/equivalent. Once you have it sorted out then go for the full flush. No point wasting money when there could be another problem.

Also, some have had luck putting a transmission solvent in the fluid and driving it. It may or may not work, clean fluid sure helps as well as the solvent, but it takes time and the car will drive poorly but slowly improve.

[vtl]

The
first owner of the car told me he changed oil
using DexIII so now it's 50/50 DexIII and jws3309

You can't use Dexron III in this transmission. Strictly JWS3309.

Also harsh, abrupt 2-3 could be B4 servo cap separated. Take your B4 cap out and inspect. If it is separated - replace with a new one, they were re-engineered a few times.

[firstv70volvo]

Thank you guys for replay

@ firstv70volvo it's going to limp mode and harsh
revers when the car is cold, when the fluid of the
tranny is hot things going to be better (Looks like
a pressure issue)
I don't hear whining. Captiva tranny will be used to
rebuild mine using valve body and some plates
and clutchs (just the internal parts)

@superHerman I changed oil just one time using 3.5
litters liqui moly with Jws 3309. But nothing
changed I'planing to do 2 more oil changes. The
color is not red like new oil. The
first owner of the car told me he changed oil
using DexIII so now it's 50/50 DexIII and jws3309
The owner told me that plates are like new no
wear traces on them. He didn't have service
history too.

My car is Laguna II I came here because MVS is the best source that I found full of information about AW55-50sn. I didn't find expert people in french forums about this transmission. And Sorry, I don't speak English very well.

As SuperHerman mentioned, first try to determine if it's the solenoids/valve body or a clogged filter. Fluid condition alone won't be definitive, pressure testing would be best. Based on your symptoms though I think you have a clogged filter or something more that sticking solenoids. Limp home mode means slippage or even a bad input or output shaft speed sensor, which are the sensors used to determine slippage internally along with the crank sensor. Sticking solenoids tend to affect garage shifts and shifting quality while driving but shouldn't cause slippage after the shift because main line pressure is applied directly to the clutches after the shift and this is where a clogged filter would limit main line pressure.
You said the car goes into limp mode right after starting it, does this happen even before you engaged R or D? Do you feel slippage or RPM flares when driving?

If you use the Captiva valve body you'll need to do the S2 solenoid swap and check for the B5 control spring as I described in my notes.
If you use parts from the Captiva transmission you have to be careful of some differences between the transmission. I think the Captive may be a 51SN transmission and yours is 50SN. If you're going to take the transmission apart I would recommend new frictions and seals and if you do swap any of the frictions you'll need to measure thickness as there can be different thickness frictions with the C2 and 4-5 clutch frictions between the transmission types.

Here's the pressure gauge I've used to check for expected pressure at the different tap points.

OTC 5610 pressure guages.jpg (354.18 KiB) Viewed 4098 times

[SuperHerman]

vtl - excellent call out on the B4 servo. Easy and quick to eliminate as possible issue.