I have had a problem with the tranny in this thing. After long highway runs (15-35) miles when I come to a stop and take off again the trans. shifts real hard sort of like a shift kit. The check engine light has come on twice and I have two different readings or they may be the same. One scanner is code 1870 and with a different scanner, it says tranny slipping. Six months ago trans fluid and filter were changed (not flushed). New t-stat 195 deg. I dont know what the 1870 code is and was wondering if anyone has had the same type problem. There is talk about this problem looking back , but not much help Thank you ahead of time jw

 

P1870 - Transmission Component Slipping

 

Make sure it is full of fluid, might not hurt to add one of those Tranny addatives.

 

For 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 12345


#77754-03K, valve for 1993-1997 all except EC3. Cost $46.00
Qty 12345


#77754-04K, valve for 1998 up EC3 units. Cost $46.00
Qty 12345

http://www.transmissioncenter.net/4L60E.htm