P1870 and Shifting Trouble
well you can look at the flat face of converter for discoloration burnish look. Ultimatley no ones going to be able to give you any easy for sure cure there are just to many variables, You can replace the valve body. That may or may not fix it but then if the converter is already damaged even with the valve body fixed the problem will still exist. And there are other possibilities too such as damaged seal on the input shaft or worn bushings in pump stator, Literally I wont advise you on what to do because it is very possible you could invest a 1000 dollars or more and still not have the problem solved 
These are some of the possibilites If you want to try them I would do them in this order.
VALVE BODY AND PWM SOLENOID OR TRANSGO HD2
CONVERTER AND INPUT SHAFT ORING NEW PUMP STATOR BUSHINGS
Honestly though while I wish you luck at a simple solution but if the trans is high milage you would likley be better to replace the trans and converter in the long run
These are some of the possibilites If you want to try them I would do them in this order.VALVE BODY AND PWM SOLENOID OR TRANSGO HD2
CONVERTER AND INPUT SHAFT ORING NEW PUMP STATOR BUSHINGS
Honestly though while I wish you luck at a simple solution but if the trans is high milage you would likley be better to replace the trans and converter in the long run
__________________
Finally!! Performabuilt asked all the right questions and gave you the answer with the right kit, 4L60EHD2. It addresses the P1870 problem, which is the valve wearing out the bore. Your converter clutch is probably burnt and or chattered. Buy a Vigilante or Yank AFTER you repair the trans. If it has alot of miles, do the trans right and be done with it. Good luck!
Wooo, So I went to a transmission place and the guy told me to first change the tran fluid, filter, and gasket, and put in Lucas Oil for Tran Slippage. So today I did all that, got it hot, took it for a spin and punched it all over the place. Light was still on so I took a break...
Then decided to take it out to buy a few things.. and the light went off on the way there!
So Im sorta happy I didnt have to spend a lot of money for the whole thing.. even though I know you should just do the whole thing and get it over with.. I really cant afford to do all that though, being at home from college with no job currently, with a lot of expenses so.
Anyways, if anything else comes up, I will be sure to let you guys know. Thanks!
Then decided to take it out to buy a few things.. and the light went off on the way there!
So Im sorta happy I didnt have to spend a lot of money for the whole thing.. even though I know you should just do the whole thing and get it over with.. I really cant afford to do all that though, being at home from college with no job currently, with a lot of expenses so.
Anyways, if anything else comes up, I will be sure to let you guys know. Thanks!
P1870 happens when the converter is commanded to lock and the PCM detects excessive slip based on engine rpm verse vehicle speed. The transgo HD2 kit addresses this or as you mentioned a new valve body but on top of that many time I have found once this code throws you are also now in need of a converter. How many miles are on your trans and whats the fluid look/smell like ?
How many miles are on your trans and whats the fluid look/smell like ?mine recently threw that code too....I just put in a new built tranny and a new 2800 stall.....i was running a 3500 stall earlier and i havnt got it tuned for the new 2800.....do u think it could have something to do with that? It never did it though until recently when i did a burn out and it did all kinds of wierd **** afterwards.....like it seemed like it was stuck locked up even when i would just throw it in drive at an idle (this only lasted about an hour)....
now its doing wierd stuff like not wanting to downshift from 2 to 1st at wot...
Any ideas man?
