Service engine soon

[79403ta]

well this is the second time my light has come on in the past 3 days...the first time i took it to autozone they said it was a wire going to the transfer case was short circuited...so i told them not to clear the code and i went to a mechanic he put his snap on scanner on it and it couldnt pull up a code..so i got him to clear the code and today it came on again so this time i went to advanced auto parts and they said the code was P1870 but they didnt have a book so i came home and was on here searching around and i found a place where it said (DTC P1870 Transmission Component Slipping)..this dont sound good and who can i believe ?? thanks in advance for any help

[sitdusa]

What yr, model is it and how many miles on it?

[79403ta]

its a 1997 Z71 350 and 4l60e its got about 165,000 miles i bought it used 2 months ago well still paying for it but no warranty... so i have no idea if its ever been rebuilt...when i changed the fluid about a month ago there was very little clutch material in the pan and there was no metal shavings..but the fluid was dark thanks

[sitdusa]

Could be a valve body problem in the transmission, I would do a transmission flush first to see if that might clear up the problem. Just changing the filter and gasket does't change the fluid from the torque converter, help me out guys if I am wrong on the flush?

[mountainboy]

Originally Posted by sitdusa

Could be a valve body problem in the transmission, I would do a transmission flush first to see if that might clear up the problem. Just changing the filter and gasket does't change the fluid from the torque converter, help me out guys if I am wrong on the flush?

what exactly is your truck doing? Is it shifting hard or slipping?

[79403ta]

it will shift hard every now and then but not regularly..when its cold in the mornings you have to rev it just a little to get it to move kinda like a stall convertor does but it will start to move around 1000-1200 rpm then after this it is fine no slipping when driving.....

[GMMerlin]

Originally Posted by 79403ta

well this is the second time my light has come on in the past 3 days...the first time i took it to autozone they said it was a wire going to the transfer case was short circuited...so i told them not to clear the code and i went to a mechanic he put his snap on scanner on it and it couldnt pull up a code..so i got him to clear the code and today it came on again so this time i went to advanced auto parts and they said the code was P1870 but they didnt have a book so i came home and was on here searching around and i found a place where it said (DTC P1870 Transmission Component Slipping)..this dont sound good and who can i believe ?? thanks in advance for any help

First question is how did the "expert" at autozone know it was a shorted wire to the transfer case?
You must understand that these guys do not have a great deal of mechanical appitude and all they do is pull a code with the same code reader you can buy and try to sell you some parts that may or may not fix the concern.

An 1870 code is a trans code for a componant slipping. This could be caused by a sticking valve in the valve body or a componant failure.
With the mileage on your vehicle, I would highly recommend that you avoid a trans flush...I have seen too many problems occur on higher mileage vehicles after the trans is flushed.

[79403ta]

th "expert" plugged in his scanner and it pulled up the code we went back inside and looked up the code and it said "transfer case switch short circuit" i think it was...but the funny thing is my 4X4 buttons would light up when you would press them and it would go into 4 wheel drive so i dont think there was a problem there....

[wafrederick]

Do not do the flush!The valve body is on top of the filter and the filter is below the valvebody.Dirt gets stuck inside crevises of the valve body,the valves get stuck and the valves stick.My father knows someone that has his own transmission shop and does valve body cleanings because someone had the transmission flushed.Do not trust that "expert" at AutoZone (really called AutoJunk) and a code reader was used to read the codes.The "experts" at AutoZone are about 99.9% wrong.There is something broken inside the transmission,there is drum oftenly called a sunshell that breaks.The sunshell is common to break inside the 4l60e transmission and most transmission parts places stock that sunshell for that reason

[79403ta]

i thought when the shell drum or shell gear broke all you would have was reverse ?? maybe i'm wrong but besides the SES light and it being a little stubborn in the morning when i first move it it is fine so i dont know what is wrong....thanks again