Code P1870 - No power, doesn't seem to be slipping

[TazMan]

Hello everyone. I'm looking for some help with a problem I'm having with a 1997 Olds 88 I picked up for my sis. It's not a 60 degree, but I think it's a transmission problem. She was driving on the highway today and she got a check engine light and the car began to give trouble accelerating. She said everything felt fine but it would only pick up speed very gradually and would take forever to hit 60 mph's. The RPM's aren't jumping or anything. Had it scanned at Autozone and got a code P1870 for transmission slippage or something like that. The way she's describing it to me it kind of sounds like she got stuck in 4th gear. The next day it drove fine. I myself drove this car over 400 miles before I gave it to her and I had no problems, but I did notice an occasional very slight harsh shift from either 2nd to 3rd or 3rd to 4th, I'm not sure which. Is there any chance this could be an easy fix like the transmission modulator or something? Thanks everyone for reading.

[cajuntractorman]

p1870

Hi
P1870 is a Type B dtc. (Diagnostic Trouble Code). That means it has to see the fault in 2 CONSECUTIVE drive cycles to turn ON the Check Engine Light.
That being said , this code is set when the PCM sees an excessive amount of slip during TCC (Torque Converter Clutch) engagement. It determines this by comparing the engine speed and the output shaft speed.
Your sis is corerect, it will "stick" actually in third (Inhibit 4th and TCC Apply).
The USUAL culprit is the Valve Body. It will need to have line pressure guage attached and a scantool.
a 3-4 valve sticking can cause this.
A Valve body spacer plate . Stuck check ball #1. Plugged TCC Orifaced filter.
It is MOST likely an internal tranny problem, doubt it is a wire issue. Could be.. but I doubt it.
You COULD try a fluid/filter change, cheap and wont hurt.
My best advice, unless your a tranny man, is to take it to a good tranny shop and have them diagnose it.
As far as lack of power, USUALLY it will shift OK up to 3rd. If it seems to be overly sluggish have the fuel filter replaced. Do a tune up. have the Catalytic converter checked. It should reach 60 semi normally, except higher rpm due to lower gear ratio.
Just advice.
I Hope this helps

[TazMan]

Thanks for all the info. She has tried to get a few tranny shops to diagnose it. Unfortunatley nobody wants to actually diagnose a tranny. They just want to replace it. Three different places have told her it needs a new one. None of them have driven it, or even opened the hood. Their diagnosis is based solely on her description of the problem. It seems everybody's a crook now a days.

When I say it seemed stuck in gear I mean as if it were stuck in 3rd or 4th gear and wouldn't downshift. When she floored the gas it would only accelerate very slowly and there was no down shift for most of the trip. Then at one point it finally shifted hard and she was able to accelerate quickly. When she got off the highway it was much worse. She still has the SES light but it's not giving her any problems right now. Unfortunatley she lives 200 miles from me so I haven't had a chance to drive it myself. I'm just hoping I didn't just give this dealer $2000 to junk a car for them as no one has the money to put a tranny in this thing.

[cajuntractorman]

1870

Hi
It well may be that the tranny is stuck in 3rd gear. An embedded check ball into the spacer palte will cause this. This will also burn the 3-4 clutches.
If it is an intermintant issue, I would have the driveability items (Tune up, fuel filter, coils, etc..) checked. Eliminate the easy and least expensive first.
Have the cat converter checked at a muffler shop (usually a free service).
Does it slip any? Slam into gears?
Try to find another shop.... I am suprised a tranny shop wouldn't want to build it.
Thanks