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DTC P1870 Transmission Component Slipping 3.8L

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Old 09-28-2010, 08:11 PM
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Default DTC P1870 Transmission Component Slipping 3.8L




I searched, and didn't find exactly the answers i was looking for.

I have a 1997 Olds LSS, 3.8L N/A.

The engine/car has 205,000mi
the trans was replaced with a 68,000mi unit from the same year/proper fit


i've driven it about 30,000mi since the transmission swap


Recently, I got a CEL - DTC P1870 Transmission Component Slipping 3.8L

I had autozone print the explanation, it said - towing/excess load, low trans fluid, OR internal trans fault.

I checked my fluid, and it was down 1qt. I topped it off, reset the code, and it was fine for about 3 weeks.

The other night, while out for a ride, the light came back on.

This time, I properly checked the trans fluid - and it was right on the money.

I have noticed an occasional "slip" in 4th gear overdrive - the car will slip about 3-400RPM'*, not violently - just kind of, a lazy variation - up down up down up down up down - until i either tap the brakes to unlock the Tq convertor, or give it more gas to downshift.


However, My tranny fluid was not flushed completely when it was replaced. They topped it off, road tested it once, brought it back in on the lifht - dropped the pan, changed the filter and gasket, and topped it off again. As we all know, this leaves about 2/3rds of the old, crappy, tranny fluid trapped in the cooler lines, in the tq convertor, etc.

so, my fluid is brownish red - and I've scheduled a transmission flush at the dealership for tomorrow (wed.) they've got the machine that draws old fluid out of the trans cooler line, and re-fills with fresh, while the car is running and the trans does all the work. They will also be replacing the transmission filter, and gasket.

SO, will fresh fluid - and fresh filter - help this nonsense, or is my code going to come back on in another 3 weeks?

the thing'* pretty tight overall, i want to get to the bottom of this

thanks,
Joe
Old 09-28-2010, 08:28 PM
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ALSO -

Tranny fluid smells burnt.

When I romp on it - I often get a "squeak" when it shifts 1st to 2nd, it sounds like tire chirp - but it isn't.

I get the same noise when i romp on it, on the highway, say - when cruise is set at 65mph, and I floor it to pass someone... it chirps when it drops the gear, then makes another noise - that sounds like the same thing, when i let off and it settles back down.

I've been told it could be my serpie belt and tensioner, needing replacement,

at any rate -

Will the transmission flush and filter help / Could my problem be simple, like bad fluid and a clogged filter?
Old 09-29-2010, 06:34 AM
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Romping takes a toll on our transmissions. (stop looking at the pile of them behind me )

There'* a couple things about a trans service that you have a little off. The total system holds ~13qts. Doing a pan drop and service requires ~6.5-7.5qts depending on how long you let it drain. I've had a pan off for a week before while awaiting parts and needed 10qts. Things do drain.

A flush can be a good thing to change fluid as long as the filter is also changed. A flush swapping out all the fluid on a trans like yours that is already beginning to show issues is not the reason the trans dies. It may however make the trans seem worse because changing all the fluid removes any friction material in the fluid and then clutches can slip better with the new slippery fluid.

With the torque converter surging you are getting, I'd try the techinfo writeup about adjusting the brake/TCC switch under the dash to see if that helps.

The code about slippage means that from the input speed sensor to the output speed sensor the pcm saw some variation that made it think your trans is beginning to have issues.
Old 09-29-2010, 07:12 AM
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How did the magnet look when the pan was dropped?
Old 09-29-2010, 01:11 PM
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Originally Posted by BillBoost37
Romping takes a toll on our transmissions.


With the torque converter surging you are getting, I'd try the techinfo writeup about adjusting the brake/TCC switch under the dash to see if that helps.


when i say romp, i really mean - run it through the gears - generally i don't abuse it, i just like to merge onto the highway safely - and get away from tail gaters.


is there a replacement option for that switch? i knew there was something down there...
Old 09-29-2010, 01:12 PM
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Originally Posted by Danthurs
How did the magnet look when the pan was dropped?


dunno yet.

on the NEW trans I had installled, the trans fluid was bright red, the OLD trans fluid was black.

the failure from the old transmission was trans shaft, it was snapped clean off.
Old 09-29-2010, 01:30 PM
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Originally Posted by JoeJetta89
is there a replacement option for that switch? i knew there was something down there...
I'd suggest checking/testing the existing switch. There is a write up in the Techinfo portion of the forum on how to do that.
Old 09-29-2010, 05:19 PM
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Well, the bad news is the dealership stabbed me with a $375.oo bill.

the good news is, they ran it on the trans flush on the machine, all new fluid, new filter, new gasket, and an inspection of all lines, vacuum, electric, etc - it all checks out.

the great news is, the car had a clean magnet - no abnormal debris of any kind, the fluid was just spent - and according to the tech, the filter had expired.

the tranny no longer goes into overdrive/tc lockup is no longer noticable, the trans no longer 'chirps' on hard shifts up/down,also from a dead stop - when you let off the brake, without pressing the gas - it proceeds forward gently by itself (which, it didn't really do before - it just kind of, sat there until you pressed the gas) and the code was cleared, about 75miles so far - not one hiccup.

i think i got lucky, the thing feels BUTTERY smooth, and we have a lot of steep hills here in MASS.

thanks all, I think this problem'* solved. GET YER TRANNY SERVICED : )
Old 09-29-2010, 05:22 PM
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Originally Posted by JoeJetta89
the tranny no longer goes into overdrive/tc lockup is no longer noticable,


(clarification - no longer goes into overdrive, prematurely - sometimes TC would lock up at the bottom/middle of a hill, get a pretty ugly shift and some vibrations - you know what i'm talking about.)


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