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  1. #1

    Default 99 slt shifts rough after about 12 miles

    We just bought a 99 k1500 slt 102,000 miles, automatic with overdrive and we have found it shifts rough from 1st to 2nd then 2nd to 3rd, but only after it has been driven more then 10 miles. When driven less it shifts fine...Any ideas...Anyone. We really hope it is some thing simple and not the transmission already

    Thanks!

  2. #2

    Default

    When you say it shifts rough, do you mean that it hits the gear changes hard and firm, or like it hunts between gears? Two totally different issues, either one could be called rough shifts.

  3. #3

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    It is not hunting for the gear it kinda stutters and it is just hard....kinda get a jolt

  4. #4

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    hmmmm... hafta think about that one.

  5. #5

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    Just a thought, with an all electronically controlled transmission (should be a 4L60E), are there any transmission trouble codes in the PCM? Service Engine Soon light coming on? I've only had my Suburban for a few months, so I'm still learning about it. From what I can gather, the shift points and the firmness/softness of the shifts is all controlled by the computer. If the computer is getting bad information from somewhere, then that could effect shift quality. These OBD2 computers seem to be pretty good at seeing faults when they exist. I think that's where I might start.
    '98 K1500 Suburban LS 5.7 L 4L60E NV246 ARB
    '92 Ford Explorer XLT 4x4 4.0 L A4LD BW13-54 Trac-loc rear
    "My toys were the greasy cogs and springs and pistons that lay around all over the place, and these, I can promise you, were far more fun to play with than most of the plastic rubbish children are given nowadays." Danny in Roald Dahl's Danny The Champion of the World

  6. #6

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    we hooked it up to the computer and it gave us code p1870 which is the control valve body in the transmission. it descrirbed our problem almost perfectly! Only problem is the part is over $400! Atleast it is not the transmission already! Thanks for the help everyone and I hope this can help others too!

  7. #7

    Default

    Glad to know that at least you have an answer now. Is that $400 for just the part?

    Steve
    10 Chevy Traverse LT AWD
    02 Chevy Trailblazer LS (110K+ miles - loaded except for 4WD - WRECKED!)
    99 Chevy Cavalier LS (105K+ miles - commuter car)
    78 Chevy Suburban Silverado (454, 3/4 ton)
    62 GMC 3/4 ton Pickup (350 police interceptor)

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  8. #8
    Master Mechanic Dr_Zero's Avatar
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    Default

    Quote Originally Posted by 99Bo
    we hooked it up to the computer and it gave us code p1870 which is the control valve body in the transmission. it descrirbed our problem almost perfectly! Only problem is the part is over $400! Atleast it is not the transmission already! Thanks for the help everyone and I hope this can help others too!
    I read this and did some searching and found this kit to fix this issue along with some other info on what seems to go wrong and how to pump up the torque some.

    here is some links
    http://www.transmissioncenter.net/PinHole.htm
    For 4L60E / 4L60E transmissions with Code 1870. This kit corrects wear in the valve body that causes code 1870. The reamer is specially designed for use with our TCC regulator valve kits 77754-03K and 77754-04K. This reamer allows the installation of our re-designed TCC regulator sleeve and valve and requires only cutting oil and a speed handle. The reamer also features a depth stop to prevent over boring. This fix will not work on GM remanufactured transmissions. The transmission doesn't need to be removed to install this part.

    #77754-R2, Reamer. Cost $125.00
    Qty

    #77754-03K, valve for 1993-1997 all except EC3. Cost $46.00
    Qty
    #77754-04K, valve for 1998 up EC3 units. Cost $46.00

    http://www.keystonekrawlers.com/Mods...ssion_mods.htm


    http://www.novak-adapt.com/knowledge/4l60e.htm
    My trucks!

    1996 GMC Suburban SLT
    1997 GMC Yukon SLT

  9. #9
    Master Mechanic Dr_Zero's Avatar
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    http://www.cahallperformancetransmissions.com/CPT Home page
    CPT Home page

    700R4 & 4L60E
    back to Tranny Guide
    Pricing Policy
    Shipping Instructions



    BASE REBUILD: Shift quality tailored to customers needs.........................................$700 + hardparts*

    PERFORMANCE REBUILD: Custom shift kit, "Corvette" 2-4 servo, .500" Sonnax pressure regulator boost valve, Raybestos "High Energy" 2-4 band, 6 Borg-Warner 3-4 frictions, Sonnax "High RPM" pump slide spring, New Borg-Warner 28 element input sprag............................................. ....$800 + hardparts*

    RACE REBUILD: Custom shift kit, Fairbanks "Billet" 2 nd servo, Sonnax "Super Hold" 4th servo, .490" Sonnax pressure regulator boost valve, Alto "Wide" Red Lined 2-4 band, 7 Raybestos "Blue" 3-4 frictions, "Kolene" friction coated 3-4 steels OR Raybestos "Z-Pack", Sonnax "High RPM" pump slide spring, "The Beast" H/D sun shell, New Borg-Warner 28 element input sprag, Sonnax "full throttle upshift sleeve" (700)............................................. .................................................. ...........$1000 + hardparts*

    PRO RACE REBUILD: Everything in the Race Rebuild + the addition of the 4L65E front support, 4L65E hardened output shaft, and updated steel piston set for the input drum. Recommended for car's hitting sub 1.7 60' times............................................. .................................................. ...........$1400 + hardparts*
    My trucks!

    1996 GMC Suburban SLT
    1997 GMC Yukon SLT

  10. #10

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