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

[bluebenzin]

The previous owner told me the filter was checked and it's clean, so this possibilty couldn't be the issue

The car most of time goes to limp mode just after starting the engine before doing reverse or D. Sometime doesn't go to limp mode especially when quickly doing 1st "manual" gear after start.

The limp mode only comes when i hear/feel a bang when changing gears up shifts or down shifts.

What does it mean slippage and flare?

After 20 minutes or so of driving shifting going to be better, small bangs in shifting, rarely limp mode. But when press accelerator pedal the RPM goes up fast (slide) than come back a little before shifting specially from 2-3.

I'm going to measure oil pressure. I find a chines 0-150 psi gauge for 60$. Does it work for me? Is it precise for 5 psi?

[firstv70volvo]

The previous owner told me the filter was checked and it's clean, so this possibilty couldn't be the issue

The car most of time goes to limp mode just after starting the engine before doing reverse or D. Sometime doesn't go to limp mode especially when quickly doing 1st "manual" gear after start.

The limp mode only comes when i hear/feel a bang when changing gears up shifts or down shifts.

What does it mean slippage and flare?

After 20 minutes or so of driving shifting going to be better, small bangs in shifting, rarely limp mode. But when press accelerator pedal the RPM goes up fast (slide) than come back a little before shifting specially from 2-3.

I'm going to measure oil pressure. I find a chines 0-150 psi gauge for 60$. Does it work for me? Is it precise for 5 psi?

In order to visually check the filter in this car you have to drill an access hole in the case under the inlet of the filter and use a borescope to get a good look at the filter. I doubt the previous owner did this so I wouldn't rule out the filter being clogged just yet.

If the car goes into limp mode before even shifting into it to gear then I'm wondering if one of the two shaft speed sensors is intermittently bad. Have you scanned the car for codes? A bad sensor reading will put the car in limp home mode but you should see a code for this. The input and output speed sensors are on top the transmission and can be remove by removing on bolt. The input shaft speed speed sensor is the one near the front of the car and output speed sensor is towards the back/firewall area.

However, the sensors may be fine if the engine RPM goes up fast when you press the accelerator then this sounds like the transmission is slipping to me and this assumes the RPMS are going up without the speed of the car increasing. This slippage is what the two transmission sensors will detect and put the car in limp mode. You should also get a code for this such as an incorrect gear ratio.

A 0-150psi gauge will be fine to look at the clutch apply pressures taps (not the SLT or lube) to determine if the filter may be clogged or other problems. In D you can check the pressure taps for the C1 forward clutch or B5 1-2 Reverse clutch, they're both applied in D at idle. In R you check pressure for the C2 and also the B5 clutch again as both are applied at idle in reverse. If the filter is clogged I would expect you'll get a low or fluctuating reading at any one of the pressure taps mentioned. In the link there's the expected psi reading you should see.

pressure tap locations
https://www.sonnax.com/tech_resources/3 ... -locations

[bluebenzin]

the transmission was opened and the filter was visually checked.

after doing a scan 3 codes was appeared, see the photo below.

I can understand the first code and it confirms what I found by multimeter when I opened VB pan ss1 resistance 17,4 ohms. higher than the normal range which is supposed to be between 13,5 and 15,5 ohms (this solenoid is responsible for reverse too).

for the second code 105, the translation could be something like " Declutch function is stoped, C1 clutch engaged" what does it mean?

The third code 106 "Changing gear" ?!

[firstv70volvo]

the transmission was opened and the filter was visually checked.

after doing a scan 3 codes was appeared, see the photo below.

I can understand the first code and it confirms what I found by multimeter when I opened VB pan ss1 resistance 17,4 ohms. higher than the normal range which is supposed to be between 13,5 and 15,5 ohms (this solenoid is responsible for reverse too).

for the second code 105, the translation could be something like " Declutch function is stoped, C1 clutch engaged" what does it mean?

The third code 106 "Changing gear" ?!

Okay, so the transmission was opened up and the filter is okay. It was opened up for a problem originally so do you know what the original problem was with the transmission and what changed after putting it all back together? Any new parts?

The S1 shift solenoids controls two shift valves in the valve body and this valve is energized/ON/Closed for 1st gear and OFF the rest of the time. The resistance is high but this would mean if it had a problem it would be when it was energized and the problem would be during 1st gear only. Just not sure if this is the problem or the only problem.

The C1 clutch is the forward clutch which is applied for every gear except reverse and N and P. The 105 code is unclear to me whether it's a C1 engaged problem (slippage) or engaged when it shouldn't be. I'm leaning towards a slippage problem being detected.

Code 106 changing gear could mean just about anything.

The gauge you have should work fine for checking the main line pressure to the clutch packs. Check the C1 clutch pressure, it's one of the easier tap points to get to too.

[bluebenzin]

Hello guys
Today I've replaced the Slu, Slt and Sls Solenoids using Rostra kit ordered from the US. The Ss1 was changed too.
Now the car doesn't go to limp mode bust still have harsh shifts up and down, very bad slam when engaging R. 2-3 Flare too. When the car is hot I have something like 2 seconds to engage D

Thank you for your help

[vtl]

I've had a similar experience with Rostra. Ended up with a remanufactured valve body.

[firstv70volvo]

Hello guys
Today I've replaced the Slu, Slt and Sls Solenoids using Rostra kit ordered from the US. The Ss1 was changed too.
Now the car doesn't go to limp mode bust still have harsh shifts up and down, very bad slam when engaging R. 2-3 Flare too. When the car is hot I have something like 2 seconds to engage D

Thank you for your help

It's not only the solenoids that can cause problems, it can also be a problem with the supply pressure to the linear solenoids due to a worn valve body. If these linear solenoids don't get the correct input fluid supply pressure they can't provide the correct regulated output pressure. If you don't want to put a lot more money into it you might consider the Sonnax Zip Kit, which is a little over $200 and contains a lot of new parts to restore the primary, secondary, and solenoid supply pressures.
If you think the internals of the transmission are still in good shape you might also consider a new or high quality rebuilt valve body for $500 and up.

https://www.sonnax.com/parts/3527-zip-kit

[SuperHerman]

Would checking the line pressure provide any insight on whether the valve body is leaking pressure and/or a seal on one of transmission internals?.

I am not as versed as some of above forum members that posted here, hopefully one will respond.

I see three situations 1) There is a problem with the transmission, maybe a molded piston is leaking (have this issue with my Audi and I assume the AW55-50 could suffer a similar problem); 2) The valve body has leaking bores due to wear; and 3) resetting the adaptations is required (I do not see you did this).

With respect to #3 - you may not be able to get the car to adapt in its current state if #3 is not the problem. It would be a last resort if the others are not the issue, plus it is good practice when many changes have been made. I have done it once with success and on two other instances I skipped the step.

With respect to #1, this has to be eliminated as a possible problem, if #2 can be excluded.

My thoughts are checking the line pressures is the first step. With this data one can decide if removing the valve body is warranted. Upon removal it should be vacuum tested for bore wear/leakage.

If it were me - I would follow what I outlined above, researching and asking questions on these points.

[vtl]

Would checking the line pressure provide any insight on whether the valve body is leaking pressure and/or a seal on one of transmission internals?

Frankly, don't think so.

My transmission had signs of low pressure that resulted in delayed engagement and even slipping frictions. firstv70volvo and I were diagnosing improper valve body function after I got my hands on it. We didn't see anything obviously out of line. I showed the videos I took to the transmission guy I know, he pointed me a couple of pressures that were not right to his knowledge. But firstv70volvo's transmission had similar pressure numbers and raise/fall timings, yet his transmission was shifting fine. For example, in my transmission I was reading a good pressure going to B5 piston, yet the third gear was totally missing.

So in order to perform this kind of diagnostic, you better have a lot of experience working with these transmission. That' my guess. It is definitely not as easy as plugging a code reader and reading a bunch of error codes saying clearly what went wrong.

Simple things, like clogged filter and total loss of line pressure - yes, you will see. But more nitty shifting imperfections you may not be able to "see" via pressure ports.

[SuperHerman]

This should help some. I did a quick read and it has great information

https://www.sonnax.com/tech_resources/1 ... nformation