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Thread: 750iL tranny problems

  1. #1
    Join Date
    Dec 2018
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    Norway
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    1998 750iL, Saab 9-5

    750iL tranny problems

    Hi all. Bought my Alpinweiss 750iL in August with no problems at 138 000 miles. I drove it about 600 miles home and had it sit for a couple days. When I started it up again I experienced delay engagement in Drive and Reverse. I also got Trans failsafe a couple times whenever I floored it in a too high gear.

    After intense reading I gathered that either a oil and filter job, or a valve body rebuild could fix this kind of problem. I tried my hand at the change first, but it did nothing(Yes, I used the Filtran filter). I am now going for the rebuild, but saw someone selling refurbished VBs on ebay so I bought one of those instead. I'd love to hear what someone with more experience has to say about it, if it is just a simple VB rebuild or something worse.

    PS: I am thinking about returning the used VB I bought and buying the rebuild kit instead. Can you use 740 5hp30 VBs for a 750 5hp30 tranny?

  2. #2
    Join Date
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    I don't have answers to all of your questions, but I believe it is common for the valve bodies to crack in those transmissions, so I would just get a rebuilt one, since yours may be cracked and leaking down pressure. Google about 5hp30 cracked valve body.

    Something also to keep in mind...these transmissions have all kinds of weird electrical things happen when the battery voltage gets low. So make sure your battery is healthy.
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  3. #3
    Join Date
    Dec 2018
    Location
    Norway
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    My Cars
    1998 750iL, Saab 9-5
    Didn't see any cracks when I changed the oil but might be internal eh? My battery had died when I checked the car last, but I had not started it for about 2-3 months so. Thanks for the help friend.

    Does anybody know if the valve body for a 5hp30 740 is compatible with a 5hp30 750?!?

  4. #4
    Join Date
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    Before throwing any money at a valve body or replacement transmission check that battery and charging system closely. 95% of trans failsafe messages are due to voltage/power! Especially if you had a dead battery recently. If volts are low the trans is usually one of the first to suffer and kicks the failsafe message.
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  5. #5
    Join Date
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    1998 750iL, Saab 9-5
    Quote Originally Posted by 740iSport303 View Post
    Before throwing any money at a valve body or replacement transmission check that battery and charging system closely. 95% of trans failsafe messages are due to voltage/power! Especially if you had a dead battery recently. If volts are low the trans is usually one of the first to suffer and kicks the failsafe message.
    Really? What is the lowest amount of battery power I should be having after a normal drive? I got P0733 code for like 30 min before it never returned. Also experienced very odd downshifting as I mentioned and delayed engagement... Will a recharge work or should I buy a new one? So many odd factors

  6. #6
    Join Date
    May 2013
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    I'd be tempted to throw the car on a charger, get the battery good and topped off. Then drive it and see if it behaves better. If it does, that points to the problem being power-related.

  7. #7
    Join Date
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    1998 750iL, Saab 9-5
    I should also explain that my battery seemed fine when the problem occured(in August) and did not die until somewhat recently when the car was stored in a garage. Its somewhat normal for batteries to die when its cold and cars sit.

    - - - Updated - - -

    Quote Originally Posted by rslifkin View Post
    I'd be tempted to throw the car on a charger, get the battery good and topped off.
    I guess thats the next plan of attack. Thanks

    What's the best interval for topping off trans oil? I heard someone said they did: 1. Fill - 2. Warm up for 3-5 min - 3. Let it cool off for 10 min - 4. Repeat
    Any mind on this?

  8. #8
    Join Date
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    1998 750iL Individual
    I would absolutely get a new battery first.
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  9. #9
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    01 Dinan 740iS, 97 318ti
    If the alternator is not putting out enough power while running, the battery being fully charged won't necessarily keep it from going into trans failsafe.
    '01 740i Sport MKIV, Quad Brake Lights, OEM Bi-Xenon retrofit, LED Angel Eyes, HID Fogs, LED Plate Lights, Dinan 7 certification, BM53 radio, OEM Sirius, Aux Input, TCU Bluetooth, Intravee II, iPod, Strong Strut, Dinan Struts, Springs, Camber Plates, Intake, MAF, CAI, Exhaust and Throttle Body

    '99 318ti Titanium Silver '97 318ti Boston Green; '96 318ti Alaska Blue (sold); '08 X5 4.8i Titanium Silver (sold); '13 X5 3.5i Black Sapphire Metallic (sold)
    '84 633csi Black (sold); '88 325iC Black (sold); '97 740iL Black(sold); '01 740iS Black(sold); '97 318ti Alpine White (sold)

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