1997 s420 transmission not shifting - HELP
 

Hello everyone. Just purchased beautiful black S420 w/130K.
The transmission is not shifting from first gear no matter what I do. I tried to go from first - up - nothing. Wanted to check the fluid - could not find dipstick. Just the thing behind the engine with the handle, but no dipstick attached. Tried OBD and received code po748 " Pressure control solenoid electrical" No idea, whether it is internal part or external and even if it is a transmission part. If there is anything you would suggest on this matter??? Greatly appreciated your help.

722.6 tranmission in "limp-home" mode. Could be simple, could be terribly expensive. The only way to get it out of limp home mode is to clear the code. Sometimes turning the car on and off will give you some temporary respite, but not if something is dreadfully wrong inside the transmission.

Anyone know the code?

Clear it and see what it does, you might need a valvebody or a conductor plate. The earlier .6's had no covers over the soliniods and would short on occasion. The reason it has no dipstick is that it uses a special synth. fluid that is not readily available. I honestly dont know if the aftermarket has caught up with this one yet. As a former dealer line tech I'd recomend servicing this unit every 60k and at 130k you might have gotten all the life out of this unit.


Joe

Hey, thanks. I see you guys know what you talking about. The way I understand is that
1) Code cleared - no change.
2) Remove the pan and replace fluid with synth. up to the previous level?? (No dipstick)
3) Look for the pressure solenoid "inside the tranny" and replace it.
4) If no better - replace transmission.
Or before doing it maybe give dealer a try???
If I've got it right - please let me know. And if you have ANY questions on VOLVO F series trucks - I'm your man :)

Starting from transmission end no. 393329 the solenoid valves are covered to prevent a short circuit due to metal chips.
In your case it may also be a contacting fault in the connector at the ETC or the transmission or a damaged wiring harness. It could also be that one of the 2 pressure regulating solenoid valves has a bad contact or is defective.

I hope this is of any help.

Carl

Thanks Carl. Do you know where to look for that solenoid? Will I see it after the pan removed?

As a more simple solution - check the kickdown (if you have it) is not permanently engaged. Sometimes mine gets stuck down, and it goes in the lowest gear it possibly can, at any speed, and will only change up if you rev it to the redline.

later

Russ

The reason that clearing the "P" code from the ODB2 system didn't help is that CODES from TRANS computer must also be cleared.
THIS is a common problem & might be simple! however it can be costly as well.
The electrical connection at the bellhousing for the valve body might be full of trans fluid & that can block data transfer fron the valve body to the computer.
We replace part number 140-270-02-50 all of the time for this problem. $10.

Gooddeal,

There is only one type of fluid available from MB at $15 a quart that can go into this transmission. Do not use anything else, even if it is synthetic. Also, the dipstick is a special tool and the level of transmission fluid must be checked while monitoring trans temp with the HHT in order to get it correct.

Sounds like you got some good info on locating your specific problem here.

This solenoid is bolted on top of the electro-hydraulic control unit which you will see when you remove the oil pan. You can unbolt this unit en will see that there are actually 6 solenoids in total.
The ones which could cause the problem are the two sitting nearest to the electrical connector. The are both identical, part # A 140 277 03 98.

Good luck.

Carl

This all going to help for sure. At this point, the pan is down and MB transmission kit is ready. They gave me 4 quarts of oil. I assume it should be the right amount. And thanks Carl and DOC for the numbers. I will get back to the dealer for them before assembling the unit. I'll let you know if it's worked out fine. Better be:) Thanks again. Lenny.

Remove the secondary pump and check for fragments of a sping or other debri. Sometimes you can remove the debri and be okay

what secondary pump? this is a .6, one pump. :-)


make sure you torque the valvebody.

be sure to clear etc.6 stand alone, clearing ME aint going to touch it.

dipstick # 140-15-21, this is right off the handle of mine, its missing a number but, the parts guys oughtta be a able to fill in the blanks.

I'd fill it to the 25c line and drive it, once it's been a few miles it should be up to temp and set the level to the bottem of the 80c line.

these really are good units but, are big bucks when they fail, in most cases a replacement requires a updated etc.6 ****rol unit.


Joe

Well, rushing to tell you that things are not so good...:mad:
Replaced all 6 solenoids, electric plate on top of the cover, connector and seal, cleaned valve cover and pan, filled up with genuine fluid, cleared the code and.... went for a road test. Still not shifting from 1st. I am ready for the whole thing changed. Unless there is something else could be done prior??? Thank you all for your replies and help. Lenny.

did you clear etc.6? thats the trans computer, a whole different animal from the engine ecu.



Joe