Check Engine Light With Code P1870 on Chevrolet 1500 Pickup

Problem Description and Possible Solution

The transmission may develop a harsh 1-2 shift and/or illumination of the Check Engine Light with code P1870 stored. This can be caused by wear of the bore for the TCC isolator and regulator valves in the valve body. This condition does not commonly occur until the transmission reaches normal operating temperature. If the valve body is worn, replacement will be necessary to correct this concern.

Problem Data
RepairPal Verified
Average mileage: 171,178 (102,000–275,000)
4 model years affected: 1996, 1997, 1998, 1999
11 people reported this problem
Viewing 1 - 3 of 3 problem details
My truck does some harsh shifting in the first two revolutions and still haven't fixed it been looking how much will it cost to fix it
i just bought a 96 silverado. wont pass smog due to a p1870 code and i 'm trying to learn how to fix the problem . any help i can get would be appreciated
tcc wont lock, harsh 1st to 2nd shift. after about 30-50 miles trans gets hot and wont shift past 2nd until it cools down.