Volvo 850 S2 Transmission Solenoid Replacement w/Pics

Post by **donc** » 29 Mar 2012, 19:16

This is a write-up on how I changed my S2 transmission shift solenoid in my 1997 850 GLT Wagon with Automatic. I performed this job with a mechanic buddy of mine on a lift and by dropping down, but not totally removing the front sub-frame. I read about people going in through the top under the battery tray and now know that this would be a tougher method to get to all nine transmission cover bolts.

Additionally, after the cover is removed and cleaned of the old gasket sealant, you still have to get the cover with the new sealant applied back on straight the FIRST time and get your bolts back in. While all this is happening no matter how well you clean off the valve body under the cover, it will keep dripping right onto the area that you want dry for the new sealant, so seconds count.

Note: I understand that people have indicated that S1 and S2 are the same solenoid. Even FCP Euro indicates this. All I can say is that on my 1997 850GLT Automatic, the S1 solenoid has the electrical connector facing AWAY from the O- ring and has an extended bolt hole for the hold down screw. It also has a black connector where the S2 is green. You will thank yourself later that you had the right parts and plenty of shop towels beforehand. Also use Permatex Ultra Black oil resistant gasket sealant or factory sealant from your friendly Volvo parts counter.

Incidentally, I did this fun project because I had a flashing arrow of doom and a check engine light on and the car was in limp mode. Going to the Volvo dealer with an active check engine light gets you a free scheduled 1- hour code reading, 222 Shift Solenoid B malfunction in this case. You get just a code reading and not a single thing more, except the recommendation to schedule a new transmission installation.

Using the below described method, it took us about 3.5 hours to get access to the solenoid, about five minutes to remove S1 and S2 and check the resistance for 10-15 ohms, replace out of spec solenoids, and about 2 hours to reassemble and refill fluid to proper level. Incidentally, the resistance for the lock-up should also be 10-15 ohms and for the line pressure solenoid should be 2-6 ohms.

Ok, ready set go…Use liberal amounts of PB Blaster or WD-40 on all screws, bolts, etc to be disconnected.

Repeat: Use liberal amounts of PB Blaster or WD-40 on all screws, bolts, etc to be disconnected.

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Disconnect battery and remove it and the tray. There is an emission pump connected under the battery tray with vacuum and electrical connectors to be unhooked.

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Next unhook the hold down for the black corrugated wire tube at the side of the transmission cover. Also, unscrew the transmission cooler line that connects to the top of the cover you are about to remove. I think it is just as easy to remove the hold down for the blue battery to engine ground from up here.

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Support engine and transmission from above. Here I used two 4x4 blocks with grooves cut on the table saw to sit in the channels of the front fenders. I used a steel 2x4 sitting on top of these blocks to bear the weight. The jacks in the front do not support weight, but keep the steel 2x4 from slipping forward. We wrapped a chain around the steel 2x4 and hooked onto a lift bracket over by the power steering pump and another near the top engine mount.

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Remove front wheels for weight and access, unbolt the steering rack from the sub-frame, transmission mount to sub-frame, motor mount bolt to sub-frame, lower stabilizer links to sway bar, front charcoal canister and bolt to sub-frame, and free up hoses and electrical wires and connectors that clip to the sub-frame.

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Make sure you remove the two bolts in the right side motor mount under the belt pulleys.

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Yea, also unplug that little electrical connector at the front of the sub-frame.

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We used a transmission jack with a 4x4 strapped across it to gently lower the sub-frame after we removed the two rear plates to the sub-frame bolts, the rear sub-frame bolts themselves, and the front sub-frame bolts. The sub-frame will drop about a foot and be held up by the lower A-arms.

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Disconnect the lower transmission to cooler line at the transmission and move it to the left.

Next: The transmission fluid temperature sensor connects below the cover and the wire runs along the left side of the cover and is in the way. Fortunately, if you follow the wire up and across the cover there is excess that is zip tied together. Clip the zip tie and feed extra wire down so you can move this out of the way. You will be glad you did!

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These bolts are tough to get out because the torx is shallow, they are rusted in my case, and they are in with Locktite. Eight of the nine came out in varying degrees of effort and the ninth on the bottom of the pan needed a hammer and chisel to help it get loose. Take your time, spray the bolts and go have a cup of coffee.

Next my buddy and I tried various techniques before the hammer and chisel came out for the last cover bolt. Also see the big rubber air hose right above his hand? Removing this from the radiator area as well as the hard plastic tube going up allows you to bungee the lower radiator forward and out of the way when replacing the cover.

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The solenoids are easy. Have the new ones on the bench. See how they are held down by one bolt each. Test the resistance and replace. Notice how the valve body keeps dripping fluid. See the easy access and why you want to be in this position when the cover is gooped up with sealant and you have to get it right the first time. It will drip at the very bottom of the valve body and you have about 10 seconds from wipe to place before the next drip comes. This is where the leak will occur if you don’t get it right.

Look at the above picture. See the fluid temperature sensor and wire running along the left side? You need to have this out of the way to get the best, one shot deal, reassembly of the cover to the transmission.

Reassemble in the order removed.

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Back in service! This whole exercise is about the involved procedure of getting access to perform this very easy replacement of a faulty transmission solenoid. Just take your time and this will be a one day repair. Use plenty of PB Blaster or WD-40 on EVERY bolt you turn. That’s it really. Start and run for a minute and shut off. Check and fill fluid as necessary. Start again and run in drive and reverse just enough to get the fluid into the valve body again. Check fluid with engine running and top off as necessary. Go for a test drive and enjoy your car again!

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Post by **matthew1** » 29 Mar 2012, 19:58

Great write up, Donc. Outstanding. Thank you. This is going in the repair database, and you're now an MVS Contributor.

Post by **donc** » 29 Mar 2012, 20:04

Thanks, Matt. I really enjoyed giving something back after your forum saved my road machine multiple times. Glad to help illustrate this repair.

Post by **matthew1** » 29 Mar 2012, 20:11

The admiration is mutual. If you want your old avatar back, put this

Code: Select all

https://www.matthewsvolvosite.com/forums/download/file.php?avatar=30106_1324255619.jpg

in either "Upload from a URL" or "Link off-site" in User Control Panel -> Profile -> Edit Avatar.

IanF · Post by **IanF** » 03 Apr 2012, 06:30

Thanks for the write up as it looks like I'll be doing this job soon.

A couple of quick questions: You don't need to drain the fluid, correct? How much fluid seems to be lost?

Thanks!

Post by **donc** » 03 Apr 2012, 10:13

I left the fluid in the pan and just popped off the front cover. I lost about 1.25 quarts. But I tend to be an overkiller, so I the next day I did yet another modified drain and flush. My 850 owners manual specs Dex/Merc fluid which I saved a bunch by buying Castrol at Advance Auto Parts on sale at about $16.00 a gallon. If you have not done drain and fills to gradually loosen up the crud in the trans, I would do that at least 3-4 times first. Its so easy and buying the fluid by the gallon makes it cheap, too. For a drain and fill, I use about 3/4 of a gallon. For Modified drain and flushes, I would use 3 or 4 gallons the first time. The trans shifts are subtle in city traffic and smooth and distinct on the freeway.

Post by **precopster** » 26 Aug 2012, 07:22

I missed this post but thoroughly enjoyed reading about the swap; a really well done write-up and very valuable now these 'boxes aren't getting any younger.

Post by **boosted5cyl** » 27 Aug 2012, 16:15

I might have to do some solenoid swapping on my V70 soon. I remember reading somewhere that you could test the resistance of the respective solenoids via the control connector beside the PNP switch. I will dig up the info and add it to this post.

Post by **boosted5cyl** » 29 Oct 2012, 08:27

OK I started on this over the weekend, but have not finished. To recap, our car has been suffering from a sluggish and sometimes harsh 1-2 and 2-1 shift when cold. I serviced the PNP switch and it made no change. Did a fluid exchange and it also didnt improve...
Here's my pointers so far for this job.

You don't have to fully drop the subframe if you don't want to. I just lowered the subframe on its bolts at the front, then jacked the motor up on the transmission end with a jack. Not best practice, probably hard on the mounts but it's another option if you are comfortable with it.

I removed both top and bottom pipes transmission to cooler for a little extra wiggle room, be sure to seal off all of the pipes\connections to prevent any dirt getting in there. I used a piece to nitrile glove and some zippy ties to seal mine.

In getting the cover bolts off, a little prep goes a long way for sure. A penetrant is definitely helpful, but I found heat to work better. Proceed with extreme caution if using heat however. You don't want to melt anything electrical and also take care to gently heat the aluminum case in the general area you are working on. Be sure to clean the head as best you can, you could even use a spare torx head and tap it gently with a hammer to get the pattern nice and clean.
If you use penetrant be sure to clean the head of the bolt before you attempt to turn it.
I ended up heating and chiseling 3 bolts off. Two were especially bad (basically had no torx head because as it was so rusted) as there is no cover on the bottom of my car and they have been in direct contact with MN road conditions.

Right now I'm stuck because the solenoids I received were incorrect it seems. On S2 solenoid I received the power connector is facing the wrong direction and for S1 the body of the solenoid is too wide to allow the nozzle to sit squarely in its bore. Resistances for both S1 and S2 solenoids were within spec and they both actuated fairly well when 12V was applied. The actuation of the S2 solenoid sounded a bit more solid however. The oring seal looks pretty worn on the S1 solenoid so that may be a contributing factor. Its also a different brand to the S2. The S2 is Aisin the S1 is not.

I need the car tomorrow so I am going to have to put the original solenoids back in. I'll clean them as best as I can and see how it goes. Maybe it'll magically improve.

Post by **boosted5cyl** » 30 Oct 2012, 12:09

Well cleaned the solenoids, put it all back together and the issue persists. With the resistance testing fine i'm reluctant to replace the solenoid now.