Hello Forum!

I am very happy to find this place, it looks like a very resourceful site with lots of information.

I have a 96 blazer that is giving me transmission problems. It is throwing a code (p1870). The main problem is that it seems to shift in and out of overdrive when I am going around 80-90 km/h (50-60 mph)

It also is slipping a bit, I have never owned an automatic tranny vehicle or a truck. 1-2 shift is fine, 2-3 slips about 400 rpm, more if I am going uphill or under heavy load.

I am mainly concerned about stopping the overdrive problem, I am assuming it is the control valve body? Or maybe a shift solenoid? Any tips are appreciated. I have no idea where to start.

If I haven't cleared the problem up enough, let me know, I will be on the site fo most of the day and will try to reply quickly! I really really appreciate the help, it is hard being a girl since I have only been working on cars for 6 months

Thanks

 

Does it slip between 2nd and 3rd shift alike 1-4 seconds and then grab and go the rpms go up and back down while this happens if so change your shift censors b censor is going mine did the same thing continental tried to rob me into a tear out and rebuild i laughed and left. Upon a little research i was right my censor was broke had 1,2,and reverse,no 3rd and 4th. Censor copper windings were broken. My truck did same thing and mine is a 96 blazer 4by4. East fix advance sells delphi oem censors for 18 dollars a piece change both drop pan drop filter and in front of tranny and valve bodt are 2 electrical plugs they are shift censor plug ins pull clips down and slide them back towards the flywheel and slide new one in push clip back up put filter in and pan fill tranny youll be rolling gaurantee it

 

Do you have a part number on the sensor by chance?