97 Grand am se 2.4 code p1870

[paul022112]

Had the check engine light come on and when I had them check the codes it came up as a P1870. I looked it up and it said that there was a sensor on the 4 X 4 transfer case out.
has anyone elese had this problem ?
I dont know weather to blow it off or is it somthing I should worry about..
Thanks for your help !!:eek: :eek:

[urweak]

Strange, that doesnt make sense at all, are you sure you got the correct code?

[paul022112]

Yea I took it to auto zone and they even gave me a print out,
This is the second time my light has came on and it gave the same code

[4kQuad]

Sorry I have nothing for you. When I hear 4x4 transfer case I think 4 whel drive unit, not a GA at all.

Does the car do anything funny when the light goes on? RPM's change, trany shifts...just looking for more info to try to help.

[mikem220153]

P1870 on your car is a transmission slippage code. My first guess is that it comes on after driving on the highway for a while.

[paul022112]

Yes that is when it came on both times, but the transmission
does not seem to be sliping, Is this something I shoud be woried about.
thanks for your help Paul

[mikem220153]

Paul;

It is definitely something you need to be concerned about. The 4T60E transmission has a history of this problem. Essentially the computer is detecting slippage in the torque converter clutch.

The torque converter in additon to turning engine torque into power for the front wheels, also acts to help push the fluid through the transmission for both lubrication and cooling. If it can't do it's job properly due to slippage, the transmission will run hotter than it should and not lubricate as well.

The most common cause of this (but not the only cause) is a worn bore in the valve body. GM, in it's infinite lack of wisdom, stopped producing tranny valve bodies made of steel and started producing them from aluminum. They did this to reduce weight on modern vehicles.

The bad side of this is that the bore in the valve body that contains the piston for the TCC (Torqe Converter Clutch) valve wears over time and allows fluid to bypass the piston. This is most prevailent at sustained speeds such as highway driving. As you drive on the highway the transmission fluid gets warmer and thins out. The more it thins out, the more fluid is allowed to bypass the TCC piston resulting in the TCC not being able to maintian it's lockup.

Here are a couple of links that will probably explain the problem better than I can:

4T60E P1870 Code Page 1 (http://www.specialtytrans.com/specialty/gm/4T60E/4t60e_tcc_slip_diagnosis.htm)

4T60E P1870 Code Page 2 (http://www.specialtytrans.com/specialty/gm/4T60E/gm_4t60e-p1870.htm)

This is a problem you will want to get checked out as soon as you can. You might get lucky and have it turn out to be a bad solenoid inside the transmisson or have the valve body repaird. But if you let it go, You could very well end up shelling out $2000.00+ for a new transmission

Good Luck

P.S. I had this problem 2 times on my 97 and I won't tell you how expensive it got!!

[paul022112]

Thanks Mike I will get it checked out soon !!
I can not afford a new tranny right now..
thank for your detailed help
Paul