Volvo RWD 900 Forum

INDEX FOR 10/2025(CURRENT) INDEX FOR 1/2010 900 INDEX

[<<]  [>>]


THREADED THREADED EXPANDED FLAT PRINT ALL
MESSAGES IN THIS THREAD




  REPLY TO THIS MESSAGE    PRINT   SAVE 

AW-71 1-2 Shift Valve Stuck? 900

Hi Everyone,

When "Cold", my AW-71 trans will not automatically upshift from 1st to 2nd gear. I can get it to upshift by manually going into Low (1st) and upshifting into 2 or Drive range while driving. As soon as the engine/trans reaches normal operating temperature, it shifts great.

Seems like a stuck 1-2 shift valve. Any commercial or shade tree products out there to free up this valve body component?

Transmission History: 7,000 miles on complete professional rebuild. Trans fluid has been drained and flushed twice. Fluid is exceptionally clean, red, and not burned. Shift linkage is adjusted properly with new bushings installed. The Kick-Down cable is Volvo OEM and properly adjusted.

Transmission shifts and performs excellent in all ranges when WARMED UP. Problem is only on every COLD start up.

Trichard: What do you think Sir?








  •   REPLY TO THIS MESSAGE    PRINT   SAVE 

    AW-71 1-2 Shift Valve Stuck? 900

    Dear Townshend Act,

    Hope you're well. I concur in the two other opinions. With 7,000 miles on it, the parts have "worn-in" as much as needed. It should still be under warranty.

    The malfunction likely is due to incomplete cleaning before/during rebuild or improper re-assembly.

    Did this malfunction appear on your first day of use, after you picked-up the car from the tranny re-builder? I ask, because this shift malfunction occurs only when cold. Thus, it puzzles me that the re-builder did not notice it, before return of the car to you.

    If the malfunction started after you had driven the car for a couple of thousand miles, I'd guess that some dirt - and it doesn't take very much - dislodged by the re-build but not removed, came loose and lodged in the shift valve.

    Please post the rebuilder's response and findings.

    Hope this helps.

    Yours faithfully,

    Spook








    •   REPLY TO THIS MESSAGE    PRINT   SAVE 

      AW-71 1-2 Shift Valve Stuck? 900

      Mobile 1 atf. Flush. My 740 had black burnt ATF when I brought the car. Flushed it out several time and final fill was with the Mobile 1 ATF. The first shift of the morning I have to let off the pedal. All good after warm .up. Check your warranty first, since it sound like dirt in the valve body.








      •   REPLY TO THIS MESSAGE    PRINT   SAVE 

        AW-71 1-2 Shift Valve Stuck? 900

        Thank you everyone. The transmission rebuilder was a "Friend of a Friend", who did a full overhaul for about half ($850) the retail price, so I guess I got what I paid for.

        He doesn't really inspire confidence. I chose to pull the trans myself and leave the 945 on jack stands at home. I didn't want the car out of my sight.

        He has good technical knowledge, but is "Ham-Fisted" and rough. Bad enough I got my rebuilt unit back with concrete burns on the oil pan from sliding it on the shop floor!

        I can take it back to him under "warranty" for sure, but I was hoping for some snake oil product to free up the valve body and save me further grief.

        I like the Mobil 1 flush idea








        •   REPLY TO THIS MESSAGE    PRINT   SAVE 

          AW-71 1-2 Shift Valve Stuck? 900

          Dear Townshend Act,

          Hope you're well. Those, who are "Ham-Fisted and rough" should not work on transmissions. I suppose that had you known this, you'd have gone elsewhere.

          Flush with ordinary automatic transmission fluid (ATF) bought at Wal-Mart. If possible, while the tranny is pumping-out fluid, move the shift lever rapidly between gears. That causes fluid to course through the valve bodies, and so might dislodge the troublesome dirt.

          Whatever the outcome, replace the Wal-Mart fluid with Mobil 1 ATF. If the troublesome dirt is removed by the Wal-Mart ATF, you'll want to replace it with Mobil 1 ATF. And if the troublesome dirt isn't dislodged, you'll want to see if Mobil 1 ATF will remove it.

          Hope this helps.

          Yours faithfully,

          Spook








          •   REPLY TO THIS MESSAGE    PRINT   SAVE 

            AW-71 1-2 Shift Valve Stuck? 900

            Thank you Spook. I like your logic.








            •   REPLY TO THIS MESSAGE    PRINT   SAVE 

              AW-71 1-2 Shift Valve Stuck? 900

              you might try

              https://www.amazon.com/Sea-Foam-TT-16-Transmission-Additive/dp/B0002JN2F4

              The directions say "...For best results use 1/2 to 1 pint SEA FOAM TRANS TUNE in the transmission fluid prior to a transmission flush or fluid and filter change. Drive at least five miles shifting into all gears. If you are not able to drive the vehicle, shift into all gears for about 3 minutes with the brake or parking brake applied. This will allow SEA FOAM TRANS TUNE to clean transmission valves and parts in each area. "









              •   REPLY TO THIS MESSAGE    PRINT   SAVE 

                AW-71 1-2 Shift Valve Stuck? 900

                And the Winner for correcting my 1-2 upshift is: Seafoam, pan drain, followed by flush with convential ATF, then fill with Mobil 1 ATF.
                All of you are winners. Shifting perfectly. No leaks!
                Thank you everyone.








              •   REPLY TO THIS MESSAGE    PRINT   SAVE 

                AW-71 1-2 Shift Valve Stuck? 900

                Might have to clean / replace the screen a few times. Problem with my trans. Is I should ,because of the lack of maintenance, flushed only the pan ATF out and ran that amount for a a few 100 miles and flush the pan two more time afterwards. I did a complete flush with the Wal-Mart ATF. The new ATF loosen so much dirt the car fail to shift twice on the highway. In the end ,I flushed it out completely ,twice. Followed with screen and pan cleaning. Third time I flushed /screen clean / gasket. Added Mobile 1. Shifts much smoother. Might clean/check the screen one more time. Old trannys need patience. . Best of luck and be careful with the small screen bolts and gaskets.. There's two gaskets and most screen kits come with only one.Be ready for ATF to come pouring down when screen is loosened. When placing the pan gasket inplace, screw every bolt slightly into the gasket with each bolt. Hand tighten evenly. For the best price on Mobile 1. Internet Ebay.....








  •   REPLY TO THIS MESSAGE    PRINT   SAVE 

    AW-71 1-2 Shift Valve Stuck? 900

    if it had NOT been rebuilt recently i would argue varnish was the cause of the ball valve sticking. my own 940 exhibited the same symtoms when i bought it years ago. the fluid was black. it took many flushes and months for it to begin to shift properly and even then it shifted hard for a while. no over a decade later its not perfect but acceptable.

    bring it back to the rebuilder and have him let it sit overnight so he can experience what you do in the morning then you can you inquire what he did wrong.

    maybe the case was not cleaned out properly before it was rebuilt.







<< < > >>



©Jarrod Stenberg 1997-2022. All material except where indicated.


All participants agree to these terms.

Brickboard.com is not affiliated with nor sponsored by AB Volvo, Volvo Car Corporation, Volvo Cars of North America, Inc. or Ford Motor Company. Brickboard.com is a Volvo owner/enthusiast site, similar to a club, and does not intend to pose as an official Volvo site. The official Volvo site can be found here.