Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

B&M Shift improver kit

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 90idahoblazer, Jun 24, 2001.

  1. 90idahoblazer

    90idahoblazer 1/2 ton status

    Joined:
    Jun 24, 2001
    Posts:
    183
    Likes Received:
    0
    Location:
    Idaho
    Hello,

    I just joined the club yesterday. Awsome sight. Fatdog sugested that I post this question here. I just purchesed a B&M shift improver kit for my 90 full size 700R4 tranny. I would like some input good or bad on the kit. I installed it but was a little leary on the instructions.
    When they tell you to install only 6 out of the 9 check balls. I have to wonder. Im a jet mechanic by trade trucks are a little forgien to me. My blazer seems to shift fine , stays a little longer through the power bands but shifts firm and positive.

    Thanks ahead of time for the inputs.

    This site is awsom, keep it going
     
  2. CaptCrunch

    CaptCrunch 1/2 ton status

    Joined:
    Feb 2, 2001
    Posts:
    3,596
    Likes Received:
    1
    Location:
    Minnesota
    I don't care for B&M stuff at all. I think it is crap... but a lot of people like it. I would recomend the Gil Younder or Tran-go kits. Also another thing is my buddy is a Tranny guy and he sees a crap load of 700r4's in w/ these kits. He says 700's are not made for shift kits... also he advicees if you have the vette servo remove it unless you have a stronger sprag and sungear shell. I'd also take a look at the fluid... drain the pan and look for cluthc shaving and crude by the magnet. If there is some there chances are it is binding. Binding can feel just like a nice hard shift.... it is also the nember one reason shift kit trannys and rebuilts that have been modified come back 10k later

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
    <A target="_blank" HREF=http://www.geocities.com/milnerlives_2000/blazer.htm>http://www.geocities.com/milnerlives_2000/blazer.htm</A>
     
  3. Derf00

    Derf00 1/2 ton status

    Joined:
    Jul 25, 2000
    Posts:
    1,683
    Likes Received:
    0
    Location:
    Abilene, TX
    Your tranny buddy gave the same advice that a local tranny guy gave me. I am curious about one other thing he told me. He said if you do not know the service history of your 700R4, don't change the fluid in it. I wanted to have mine serviced and checked out, but he advised against changing the fluid. He said you are asking for trouble if the transmission hasn't been serviced properly and you change the fluid, as long as it is full and not burnt, leave it alone.

    What's your opinion?

    Derf00

    "Four wheel drive allows you to get stuck in a more inaccessible place."
     
  4. Thunder

    Thunder 3/4 ton status

    Joined:
    Jul 20, 2000
    Posts:
    8,946
    Likes Received:
    1
    Location:
    Northeast Nevada
    Murphys law definatly applies in 700r4s. if it works dont mess with it. 700r4s are a very touchey tranny. They usually dont like aftermarket shift kits. Many times these kits result in tranny failure. They need other mods in valving, lubrication, and other stuff if you are going to mess with the shift points.
    They are a good tranny just as they are. I would not modify one unless you really know what you are doing.
    The best thing to do to a 700r4 is to change the fluid at least once yearly and run a good tranny cooler.
     
  5. 90idahoblazer

    90idahoblazer 1/2 ton status

    Joined:
    Jun 24, 2001
    Posts:
    183
    Likes Received:
    0
    Location:
    Idaho
    wow alot of mixed feelings on shift kits.. I would like to know if anyone has had a bad experiance with one. Did I make a bad move by putting one in my 700R4.

    Thanks
     
  6. Thunder

    Thunder 3/4 ton status

    Joined:
    Jul 20, 2000
    Posts:
    8,946
    Likes Received:
    1
    Location:
    Northeast Nevada
    I dont think you made a bad move installing the shift kit. It will probablly be ok because you have a 1990. GM modified the 700r4 in mid 1988. They gave it better lubrication and made it a little stronger. As I said before Keep the fluid clean and cool. Dirty burnt fluid is the 700r4s worest enemy. Because they have a overdrive they need the best in lubrication.
    Oh by the way. Welcome to the board. Where in Idaho are ya from? I go up there all the time. mostly to the Twin falls or Boise area.

    <font color=orange>GOT HORSEPOWER?<P ID="edit"><FONT SIZE=-1>Edited by Thunder on 06/25/01 07:27 AM (server time).</FONT></P>
     
  7. CaptCrunch

    CaptCrunch 1/2 ton status

    Joined:
    Feb 2, 2001
    Posts:
    3,596
    Likes Received:
    1
    Location:
    Minnesota
    hmm... haven;t heard that one before derf... I have heard not o chaange it if it is all black or burnt cause the tranny miht not shift when you are done, but never the other way around. The main problem is alot of shops don't know how to properly rebuild and modify them to fix their factory problems... even the 88 update still leaves problems in the 2-3, weaknesses in theshell and sprag. I like the leave it alone thing... just cause it isn't ar ace tranny or even a performance tranny.. it is aplain jane street driver tranny for milage and efficiency... Although my buddy has one 700 perfected and it is surviving behind his 500 hp BBC w/ no problems... But he has a lot of work invested in it. I think he said parts and labor if he was to do it would only be like 1800. Most stock builds are in the 12-1500 range.

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
    <A target="_blank" HREF=http://www.geocities.com/milnerlives_2000/blazer.htm>http://www.geocities.com/milnerlives_2000/blazer.htm</A>
     
  8. Wheels

    Wheels 1/2 ton status

    Joined:
    Aug 18, 2000
    Posts:
    638
    Likes Received:
    0
    Location:
    Native Floridian living in Oklahoma, USA
    Shift kits in a 700 are okay as long as you stay away from the corvette servo (093). This will eventually eat up your tranny in the heavier K5. The reaction gear shell will develop stress cracks (high failure area) and eventually fail. Stay with the 553 (V8) and avoid the 554 (V6) servo. A shift kit basically takes the family lazy shift out and puts the firm shift in. On a stock tranny, when it shifts, the previous gear and the next gear are apllied together and then the previous gear releases (ie first, first/second shift, second). A shift kit takes out the middle part and leaves you with one gear at a time. Result is a firmer shift feel. The 2-4 servo only applies the band in 2nd and 4th. This is where the corvette servo comes into play. The larger apply area applies the band with extra force. On a heavier vehicle it causes the undue strees on the reaction shell where the reaction sun gear fits in. When this cracks and seperates, no reverse is the first sign and loss of power and eventually a trashed out tranny. You'll hear about people or rebuilders recommending a corvette servo. It'll work if you don't romp on the pedal, but over time it will fail early. My nickle.
     

Share This Page