AW55 hard downshifts.

dikidera · Post by **dikidera** » 04 Nov 2022, 02:40

I have a 2005 s60 140hp NA, with the AW55 transmission. When I got the car, I knew the owner had never done a tranny flush for at least the 3-4 years he had it.

The car had rough shifting, not a whole lot, but definitely not smooth. The tranny has a kick down function to drop 1 or more gears. So a 3rd to 1st should be possible or 4th to 2nd, but I am no expert on this.
The kickdown is very rough, there's hesitation on the car for at least 1.5s. From other people who've had good AW55 trannys, they said it shouldn't hesitate.

So I did what any reasonable person would do, I did a drain and flush. First time, from the drain plug came out only 3.5l or so, then after around 500km or so, I did another drain flush and this time around 3.8l or so. So for a total of slightly above 7l(7.5 quarts for you imperial guys).

But the kickdown remained the same, I noticed almost no improvement. I have spoken to other people who have this tranmission and no one has complained for rough kick downs.

The description is as follows: I slam the gas pedal, the rpms start climbing in the same gear for you know, a split second, then after that does the transmission drop a gear or two but it is a hard downshift. People have described the feeling as a bump, I would describe it as if the car is being pushed backwards.

https://streamable.com/c6zwzm

Btw, my lower torque rod is shot, and I will be replacing it with a Volvo branded original one, if that doesn't solve the issue, then I am not sure any more drain flushes will.

Post by **kallekula** » 04 Nov 2022, 04:17

Sounds like sticking linear solenoids.

dikidera · Post by **dikidera** » 04 Nov 2022, 06:54

Thanks for the reply. I can buy a Rostra set(not very expensive at all), I am just not sure if the bore(the place you insert the solenoids in) is worn or not as that could be possible as well and that can't be fixed afaik without a new valve body.

Post by **vtl** » 04 Nov 2022, 08:54

www.amazon.com/gp/product/B0016IUWIA (need to replace one on/off solenoid from your old VB).

Volvo 1161640.

All you need. Don't cheap out on ATF, a few bucks is not worth it.

dikidera · Post by **dikidera** » 04 Nov 2022, 09:16

vtl wrote: ↑04 Nov 2022, 08:54 www.amazon.com/gp/product/B0016IUWIA (need to replace one on/off solenoid from your old VB).

Volvo 1161640.

All you need. Don't cheap out on ATF, a few bucks is not worth it.

I don't think I've cheaped out on the ATF, I bought Aisin Premium 6 ATF which is made by Aisin, and says it covers and even exceeds the JWS3309 spec, although I've heard Volvo's version has some specific additives that these do not. Just heresay though and nothing to back it up with.

Post by **vtl** » 04 Nov 2022, 09:26

Volvo adds a lot of friction modifier to its ATF. Also it is thicker in hot temps than most of JWS-3309 compatible ATFs.

Post by **jonesg** » 04 Nov 2022, 21:04

If you never stomp on it, it never happens.?
I pay attention on hills, don't get behind the torque curve.

When I first got the car I stomped on it all the time, its a lot of fun , then the turbo blew up, I don't do that any more.
I suspect theres a bit of abuse behind failures.

Post by **Blacklab467** » 04 Nov 2022, 22:23

I would consider a Transgo shift kit to rebuild the linear solenoids and upgrade the valve body, also do the B-4 servo upgrade. I had good success with both of these. There’s a limit to how much you can improve things with drain and fill, plus it’s expensive. How many miles on your car? Does it bang from neutral or park to drive or reverse? Any shift flares? Read up on the TransGo kit, it’s a quality product and only costs about $120.00.

dikidera · Post by **dikidera** » 05 Nov 2022, 02:38

Blacklab467 wrote: ↑04 Nov 2022, 22:23 I would consider a Transgo shift kit to rebuild the linear solenoids and upgrade the valve body, also do the B-4 servo upgrade. I had good success with both of these. There’s a limit to how much you can improve things with drain and fill, plus it’s expensive. How many miles on your car? Does it bang from neutral or park to drive or reverse? Any shift flares? Read up on the TransGo kit, it’s a quality product and only costs about $120.00.

Funny you should mention the "bang".

Ok, so let me add a few more details. When the car is in Drive and I am holding down the brake, there's vibration in the car, this is either bad mounts or...I've heard it could be the torque converter. When I go from Drive to Neutral the vibration goes away but there's a also a kick going from Drive to Neutral(or Park) and maybe a clunk. My theory here is that when the tranny is in Drive the clutches are engaged and torque is being transferred to the wheels, but I am holding the brake, so there's torque and the engine+tranny are turning on their axis and putting load on the mounts and when I go to Neutral, the clutches disengage and everything calms down so the tranny+engine go into their resting state and no load on the mounts but in doing so its like letting go of a swing and so that is where the kick could come from.

Remember when I said clunk? I have clunks when braking as the transmission is shifting gears or whatnot. I do have a shot lower torque rod, but I am not sure if only that one explains everything. I bought the original one from Volvo and plan to install it very soon and maybe see if I can add a few washers to the axle bolts and see if they were loose.

As for flares, not the traditional type in my opinion. See I am a stomper so I can slam the pedal and let it go within say 2 seconds, in that time as the transmission is determining what to do I notice it engaging at around 3k and then 2k and then letting go into Neutral?
Yeah I've basically noticed the transmission going into Neutral if I am at a high speed and completely let go of the gas pedal I can see the car driving at say 25-30mph yet at 750RPM which to me means Neutral.

You can see it in the video I posted, as I let go of the gas pedal completely, there's an engagement for a brief period at around 2800k before the RPMs again start dropping to below 1k which is in Neutral territory pretty much.

EDIT: Holy hell guys, the upper mount was completely shot, the one held by the strut bar.

dikidera · Post by **dikidera** » 12 Nov 2022, 07:57

A small update and I hope someone can chime in with ideas.

I replaced the hideously worn upper torque mount, the lower torque mount and the right side engine mount which was also very bad. The 2 big ones will be replaced saturday as they have not yet arrived.

What I noticed is there is still clunking when letting go of the gas. The gearbox still hesitates with kickdown although some violent kicks don't occur with the new mounts but the hard downshifts are still there. Idle vibrations have unfortunately increased..and this time they increased more from before when I was in Park.