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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!
 

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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.
 

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

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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.
 

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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!
 

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

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99Bo said:
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/GM/4L60E/4l60e_transmission_mods.htm


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

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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*
 
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Awesome info. I'll look later, but I wonder if there are any similar mods for 4L80E owners.
 

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that is awful high considering that most parts stores have it listed for around $25.00 needing the parts for that myself right now is the only reason i know this for a fact. putting it in... well that may be another issue. but not putting it in i am looking for a full on rebuild i just know it.
 
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