2000-2008 AW55-50SN Valvebody re-assembly

[Phixion]

1st time poster on here, but love reading up topics and threads on here. I normally frequent SS regularly and before my current '04 S60 2.5T I owned an '01 S40 for a few years. Hate digging up old threads, but this one is relevant and quite helpful to my situation...

My S60 has had some trans troubles or issues rather for some time. I'm currently at I dunno how many miles (guesstimating about 160k as my odometer froze at 123k due to a BCM fault that's really an ECM issue to the power for the BCM). But at around 114k miles I did a complete trans fluid exchange (full case of Mobil 3309) by way of the Gibbons method. The fluid I pumped out was the original factory fluid which I sent a sample off to Blackstone and they deemed it is in not too bad of shape. I changed the fluid as I was having some flair issues. This has since progressed some since then, though it did clear up a bit for a while after the fluid exchange. The issue I currently have is that when the car is warm, it'll shift hard. But by warm I mean if I've been in traffic or at a point where the cooling system cycles, so over 200F. Once the car cools back down to the 180's, the issue clears up and all shifts are smooth, though I've always had a slight 2 -> 1 downshift bump almost always. When the car is cycling the cooling system and the trans acts up, I get a good 1 -> 2 flair, and a terrible 2 -> 3 flair and bang into gear if I don't let off to let it shift a little smoother when I feel the flair happen. I've learned that if I have the A/C run in traffic or slow moving situations, I can keep the temps down and prevent the issue. Originally I was thinking to me it seems like a heat soak issue since it only happens when the cooling system cycles, and then calms down when the operating temps drop. So for that I bought a new Nissens radiator and also acquired an XC90 transmission cooler to use in place of the standard "cooler." I don't have evidence of cross contamination between fluids in the radiator, but I've heard it's not uncommon in these types of radiators. After reading the technical sheets from Sonnex, I'm almost certain my issues are the 3 main solenoids being clogged and/or needing rebuilding or replacing. Do my symptoms and issue seem fairly text book of what new SLT, SLS and SLU solenoids would fix? I'd honestly prefer to do this without removing the VB which I have read is totally possible though not ideal. FWIW I've emailed IPD who confirmed that I should have the latest B4 servo cover, though were there any revisions to it after 2004? TIA

[Blacklab467]

I'm not a transmission specialist but I had the same issues as you but not with an overheating issue. My transmission had a 1-2 flare, a really bad 2-3 flare that seemed to be worse when making left turns, and it would SLAM into reverse or drive from park! I initially thought it was motor mounts for the slam into drive or reverse so I changed all the motor and trans mounts (5 of them) with OEM parts. Not much change although all those parts were worn out and 1 mount was almost completely separated. Next I changed the B-4 servo......no change either. Then I changed the fluid via the Gibbons method.....no change. Then I started reading about how the transmission does what it does and decided to do a Transgo shift kit which mainly addresses the 3 solenoids that you mention plus a couple other things. It was a relatively long but easy job with well written instructions, obviously you will have to take off the valve body and disassemble it partially but thats not difficult. Oragex has a good video of how to lower the subframe to access the valve body and take it off.
The results were spectacular! The transmission shifts like new, no flares, no banging going into gear, I actually didn't even do the adaptive relearning after the job was done. The kit has very good instructions and 2 specific size drill bores to clean out the solenoids and costs about $130. Some people recommend just buying new solenoids but I chose to "clean out" my original ones. At the time my car had 260,000kms on it and probably the original fluid.
If you go on Sonnax's website you will find a pretty good explanation as to what each solenoid and band is responsible for and maybe that will help with the troubleshooting, I have no idea what your temperature issue might be or how it is affecting your shifting. My car didn't have any temperature issues related to the transmission.
These transmissions seem to not wear out but rather, have issues that are often related to fluid contamination, largely affecting parts with small clearances like the valve body and solenoids.

[Blacklab467]

BTW; its about 95% of the job to get the transmission pan off to access the solenoids so you might as well pull the VB off for the extra 5 minutes it will take you. Then you can clean it all up and work on the bench, you won't need to replace any of the VB gaskets if you're careful but they do provide them in the TransGo kit if you do.

[firstv70volvo]

You're symptoms sound like sticking linear solenoids at high temperature. Less likely but still possible are worn valve body parts affecting fluid pressures at higher temperature. Because you're having what sounds like severe flairs at higher temps I would say it's more probable the linear solenoids are sticking.

How are the garage shifts when the transmission is hot? P to D, P to R? Any delay or bumps? r

There's a good chance rebuilding or replacing the linear solenoids are going to fix your shift problems. Replacing the valve body offers an even better chance of fixing the shift problem if the problem is the solenoids and/or worn valve body although a higher cost option.

I don't have experience with the Rostra solenoids or rebuilding the solenoids with the Transgo shift kit, I do have experience replacing the valve body.

These are the options I know of and the approximate costs including free DIY labor charges.

AW55-50sn or 51sn shift problems options (assuming it's the linear solenoids or valve body)
1) Transgo shift kit ~$100, linear solenoid rebuild kit and some drop in valve body parts
2) Sonnax shift kit ~$210, comprehensive valve body drop in replacement parts, no solenoids or parts to fix the solenoids
3) Rostra linear solenoid set ~$120 new linear solenoids, not OEM parts but new and some say a better design
4) AC Delco valve body (OEM Aisin part) ~$500 new OEM valve body which includes all new solenoids, requires one shift solenoid swap and check for B5 valve spring to make compatible with Volvo.

Volvo small cover gasket and 2 valve body to case seals ~$20, required when removing the valve body

Like Blacklab said, most of the time and work needed is getting to the valve body solenoids and for all but the Rostra solenoid replacement option you need to remove it, the Transgo kit also has some valve body part to replace.

[Phixion]

Thanks for the replies Black lab and firstv70volvo! Definitely some helpful and promising stuff there. Perhaps the Sonnex kit + new Rostra solenoids might be the ticket. Are Rostras only available on eBay or are there actual reputable dealers of them that sell the genuine product? As for my trans, there are no issues shifting into gear when the car is hot and not in motion. No bumps into reverse or issues going from P to R to any other selection and vice versa. I think that you're spot on firstv70volvo with the high pressure issues in the VB caused by sticking solenoids, at least my reading of the Sonnex AW55 technical document seems to point to that given my symptoms and tracing what issues with each one causes. I'm not sure how the engine cooling plays into affecting the issue, but it definitely does affect it.

[SuperHerman]

I will add a couple of comments. I used the TransGo kit with good results. Not a difficult job, just follow directions. I also used Valvoline MaxLife and was in and out for under $200.00.

The worst part of the job was removing and cleaning up the RTV Volvo uses rather than a gasket. You can buy a gasket for a Nissan Maxima (and other cars) that is an exact fit as they also use the same transmission. This makes going back in if you have problems much quicker. It was under $10 when I did mine a number of years back.

Some have had luck just using the Rostra solenoids and leaving the VB on. Some have had luck just changing the fluid, others fluid and some SeaFoam Transtune.

So, if you are willing to throw $35 out the window and have sub-par skills (assuming you have not done a drain and fill) the starting point would be to do a drain and fill with Valvoline MaxLife and SeaFoam TransTune and run it for 200 or so miles and see how things go. Measure what comes out so you get an idea of how much to put in. Usually it is 2.5-3.5 liters or so, if I recall.

One word of caution - the transmission drain plug is on the bottom of the pan - not up top. The thing that looks like a drain plug that is higher up is NOT a drain plug and will cause issues if you remove it.

There are write ups if you have any confusion.

[Blacklab467]

I would also suggest that particulate contamination in the bores of the solenoids (think copper micro bushings) would not likely become dislodged with additives like SeaFoam, maybe but I doubt it.
The other note is that if you use and "refurbish" your existing linear solenoids, as opposed to replacing them with Rostra's, the calibration will already be complete. You just keep them with the factory original setting. I'm not sure how the new Rostra's are set when you buy them but I'd hate to have to get back in there to make an adjustment that you don't even know if it will work. For this reason I would stick with the original solenoids and rebuild them with a Transgo kit..........some may disagree with me on this one.

[abscate]

One word of caution - the transmission drain plug is on the bottom of the pan - not up top. The thing that looks like a drain plug that is higher up is NOT a drain plug and will cause issues if you remove it.

Like $XXXX of issues to remove and go inside the transmissions, where XXXX is large. That upper bolt captures one of the transmission brake bands so if it comes out, your car is INOP>

[firstv70volvo]

Thanks for the replies Black lab and firstv70volvo! Definitely some helpful and promising stuff there. Perhaps the Sonnex kit + new Rostra solenoids might be the ticket. Are Rostras only available on eBay or are there actual reputable dealers of them that sell the genuine product? As for my trans, there are no issues shifting into gear when the car is hot and not in motion. No bumps into reverse or issues going from P to R to any other selection and vice versa. I think that you're spot on firstv70volvo with the high pressure issues in the VB caused by sticking solenoids, at least my reading of the Sonnex AW55 technical document seems to point to that given my symptoms and tracing what issues with each one causes. I'm not sure how the engine cooling plays into affecting the issue, but it definitely does affect it.

When I began to have shifting problems they were garage shift problems at hot temperatures and one of the things I had read about with the linear solenoid sticking was a coating they put on the bushing that caused the problem. Also read the bushing can build up dirt and debris over time causing the pintle to stick in the bushings. When I replaced the valve body I checked the old linear solenoids I pulled off and 1 of 3 was sticking and at room temperature. I pulled it apart and it wasn't dirty but it did look like there's a coating on the bushings (see photo). Using a drill bit I could shave the coating off and free it up, the Transgo kits uses a drill bit to clean out the bushings. The coating is a dark color and pretty tough. I never put these linear solenoids back in so i don't know if this would have solved the problem but probably would have, a sticking linear solenoid is bad news for shift quality. Sonnax also offers rebuilt and calibrated solenoids although I don't know the price and I think you have to buy them from a dealer.

[SuperHerman]

Firstv70volvo - What you refer to as "coating" I believe is buildup. In the TransGo kit two drill bits are included - using the one that properly fits, one hand turns the bit into the solenoid, where the pintle slides, and cleans the build up. It is all in the instructions, there are also videos of people doing it.

On the few valve bodies I rebuilt with the TransGo kits, I also gently cleaned the pintle shafts with a green scotch brite.

From what I read with the Rostra valves, they are plug and play, but I understand and appreciate the tuning that may be needed. Another reason to use a real gasket.

In all, the TransGo kit is the $200 solution.

Some have had luck with the SeaFoam TransTune treatment - if one lacks mechanical skills it is worthy of a try.