850R AUT hard shifts

[oragex]

Uhm, hard to explain. When I go full throttle I'm getting boost. But after the gear change the boost is a lot less. And it goes in gear with a bit of a bang. (Not hard) It's harder in 2-3.

That sounds pretty much like clogged solenoids

Haven't been through the thread, if the solenoid is activated (powered at the battery), the electrical actuator should be fine

The other thing is whether the two bushings inside are clogged or not, main issue for hard shifting. To test these, I've put them in hot engine/transmission oil (warning, the oil can get on fire) and test them. The bushings may slide fine when the solenoid is cold, but dilate and get stuck at the operating temperature (around 80C) @34:20

By all means, send them to a place who opens and replaces the two bushings and ask specifically to keep the exact adjustment on each solenoid

Note that the valve body can also have an issue.

[kevinwalter]

That could be possible. The resistance of S2 is to high. 15.8 ohms.

Maybe just buy new solenoids? But why I don't get a code for a defective solenoid?

[kevinwalter]

Just measured my old transmission. Found out the following:
___OLD TR____NEW TR
S1 16.9 OHM___14.2 OHM
S2 14.0 OHM___15.8 OHM
LP 3.4 OHM____3.8 OHM


My Old transmission gave me a S1 error code sometime. Reset the computer and it never came back. But as far as I can see that solenoid has to much resistance. S2 has to much resistance on my new transmission. Maybe just swap the S2 solenoid?

[hausmeister]

idle should be 850rpm

So this is a bit to high?

imo yes. Might not be important though.
You could try to look for leaks in the intake/vacuum hoses... try to pinch the idle air controller hose see if it makes any difference (rpm should go down). If not then there is some leak.

[Sommerfeldt]

The numbers for all 850 engines are 800-900 RPM, except B5254S and B6304F, which are 750-850 and 700-800, respectively.

- S

[kevinwalter]

To test it I disconnected the idle valve. It should go off right? It still ran if there was no problem....

[kevinwalter]

Tested the car today, it's shifting good from 3-4 but all other shifts are a bit jerky. (Also back from 4-3 is good. 3-2 is jerky and 2-1 is a bang.) Reverse is a hard bang. You can hear something clicking in the transmission when you put it in reverse. A half a second later it engages the gear with a bang. (only when the oil is hot)

Is it possible that solenoid S2 is shot without generating a faultcode? 1-2 and Reverse is using S2. The shifts without S2 are working fine.
I enabled all the solenoids with the Volvo System Tester. The whole car shifted much smoother! But after it cooled down a bit it was jerky again.

What do you guys think?

[Sommerfeldt]

There's a threshold for everything, so it's certainly possibly that it could be failing, at least. If your tests show it to be the problem, then you've pretty much done everything right, and found the cause, I'd say. The key to these cars is meticulous troubleshooting before you start throwing parts at it, and it seems to me that that's what you've done.

- S

[kevinwalter]

Alright, will change the solenoids after the holiday.

http://transpartsdirect.com/aw50-4042le ... 11996.html
http://transpartsdirect.com/aw50-4042le ... 11997.html
http://transpartsdirect.com/aw50-4042le ... 11994.html

I will change them all.. They are not realy expensive. But I want to change the Line-pressure solenoid to. Is that a common exchange? I can't find them on this website.
http://transpartsdirect.com/advanced_se ... =2a&page=1