700r shifts at partial throttle

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by tommyboy, Apr 18, 2000.

  1. tommyboy

    tommyboy Newbie

    Apr 11, 2000
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    My 89' Blazer with a 4" suspension and 3" body lift, running 35" tires sometimes shifts out of third gear between 40 and 55 mph only after I hit a bump. It will be running at about 2000 rpm and the rpms will drop to about 1600rpm and I am driving the truck in drive, not over drive. The tranny was rebuilt a year ago and it didn't do that prior to the rebuild. I went back to the shop that rebuilt the tranny and they said it was because of the lift and tires. That I find hard to believe ! Any ideas, I am kind of sick of listening to it down shift every time I hit a bump.
  2. 6.2Blazer

    6.2Blazer 1/2 ton status

    Feb 24, 2000
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    Did it do this before you installed the body lift?
    Sounds like the shifter linkage is not properly adjusted, or maybe getting worn out, that the shock of the bump is physically knocking the shifter/linkage into the OD position.
    Maybe the body mounts are getting worn out and allows movement between the body and frame (and therefore the trans).
    There's really nothing the suspension lift or the tires could have affected to cause this condition. When you have a problem with work a shop did, they will almost always try to blame it on something else and lifts and big tires are just real easy to point out, even if there is no way they could be causing the trouble.

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