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.
Check Engine Light With Code P1870 on Chevrolet 1500 Pickup
Average mileage: 171,178 (102,000–275,000)
11 people reported this problem
1996 Chevrolet 1500 Pickup 275,000 mi, Visitor
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
1996 Chevrolet 1500 Pickup 230,000 mi, Visitor
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
1997 Chevrolet 1500 Pickup 210,000 mi, Visitor
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.