2000 Chevy Astro/GM transmission "service engine soon" light problems

astro
chevrolet
code
transmissions

#1

I had a P1870 “service engine soon” code to pop up on my Astro van making it fail inspection. The only noticeable glitches were occasional pauses between two gears on the auto trans and a rare “clunk” when shifting.



I contacted several shops and finally paid just over $1,500 for a “transmission rebuild” Driving back from the repairs the “service engine soon” light came back on and the van is shifting worse than ever. I phoned the mechanic and they said their warranty applies and they will try a “new” valve body for the trans. when I bring it back.



My questions are:

Is there a “break in time” for a rebuilt transmission [as the mech. said]when it might “shift erratically”? [never noticed this on new cars]



Should a valve body be replaced on a “trans rebuild” as a matter of course?



Does what was a minor trans problem with a P1870 code cause inspection failure in states other than N.C.?



Anyone else experience this problem or knowledgeable in this area?


#2

Was that the “service engine soon” light or the CEL (Check Engine Light)?


#3

That would be the “service engine soon” light, thanks never new of any other lights. The P1870 code is what came up again after the repairs. I pulled into an Advance shop or some such and had the code read for free on the way home.


#4

Hmmmm…what kind of a mechanic is this? Is it actually a transmission specialty shop? B/c something doesn’t add up - like the price. No one is going to do a real rebuild on this thing for $1500. So if you really want some help you might ask them for a list of exactly what they did in the rebuild. (E.g. a quickie “rebuild” would just involve pulling it apart and then just slapping it back together with new soft parts, but there is a lot more that needs to be done).

In general, a valve body wouldn’t always be replaced - i.e. its not a matter of course for just any transmission. Maybe it is for this one, I don’t know. If your error code is still the same one then the need for a new valve body is plausible - but see my first point. These guys probably don’t know what they are doing since if the valve body needs to be replaced they should have known that to begin with.

It is possible to have some less than perfect transmission behavior after the rebuild - I don’t know that one would call it a “break-in” period, but it would have to do with the computer relearning how you drive. I don’t know if this would apply for your transmission or whatever job it was they did, but if your code is still P1870 then this is not your problem.


#5

They advertise as a transmission shop plus other work. I believe they tried to give a verbal list of stuff over the phone before the work but the details were not on the receipt.
::::EDIT:: UPDATE::: Here is a cut n paste from my post below

Well I got the van worked on again today [Fri 8/21/10], he said he was waiting on a valve body and that he put “new seals” in - something you do whenever you break it down?. No extra charges, said all the work is under the warranty - good so far. The van drove ok back home and I got a list of the parts replaced.

Converter,Banner,Filter,band,shell,solenoid pack & shop supplies.

Would the valve body be the “solenoid pack”? I am still driving with an expired tag as I have to put enough miles on it for the “computer to reset” or whatever. Funny but when shifting between 1st & 2cd or the lowest gears it still hesitates a bit but does not make a clunk noise…yet, maybe that is just typical for the van.

:::::::jEND EDIT:::::::::

I spoke with 4 or so transmission shops on the phone and one in person. Two of the shops had the lowest $1500 price; one with a one year parts & labor warranty and one with a 3 year parts & labor warranty [the one I chose]. The one year warranty was a national chain that would honor the warranty anywhere these 3 year guys are local but that is where I use this service van the most.

I noticed the bottom of the tranny was still pretty hot hours after the drive home on the interstate and it seems to work almost ok when first starting off cold. I have read and heard that the P1870 code is “a general transmission problem” to it being a specific “valve body problem” depending on the exact trans. I also thought more precise information would be available to a specialist.

What really ticks me off is being jerked around by the state not being able to renew my now expired tag until the “generalized problem” is fixed. NC has a rule you can “apply for an inspection waiver” after spending $200 trying to fix a problem. So that means all the manufacturer has to do is program a light to come on for any trivial reason and the consumer has to throw money at it to use the vehicle. I agree with safety inspections but this fuzzy line of demarcation is designed for abuse by the car repair industry it seems to me. [A lot of local politicos and their contributors are in the car industry, sales & repair, in NC.


#6

P1870 is about the transmission slipping. This is may be what you are feeling as a pause between gears and may also lead to the clunk-type shifts on occasion as the computer pumps up the line pressure to reduce the slipping.

I am going on very general knowledge - nothing particularly specialized. However, if you want the best help you can get here a complete list of what went into this rebuild may help others give you specific advice. (There is a trans specialist who comes by the boards on occasion).


#7

GM products notoriously stores codes. The code is very likely a seperate issue that has to do with the emission system parts only. Or it may be as minor as a bad fuel cap. All this emission stuff is a racket anyway. You probably have a Liberal Governor. Definetly have the throttle body replaced, which should have absolutely no problem if they did quality work and really did replace the throttle body if a new trans was put back in. Either way, a reputable shop would have replaced the throttle body anyway during rebuild since this is mostly where issues are.
As far as the code issue goes. Go to a convenience parts store and have them hook up their hand held computer to the car. Thats all they’re good for anyway. If you have a clerk who is knowlegable and agreeable he can find the area in his handheld that says “Clear Codes.” My Son does it all the time and you wouldn’t beleive the garbage they dictate to him to pass on to the consumer. My Ram 1500 had a code problem that only came on when the outside temperature was below 20 degrees (Beats the heck out of me), and only during that specific condition (???). Sonny and I found an unrecognized area in the handheld that tells the computer to erase, or take a code out of memory. Can you just imagine how much money a dishonest shop can perpetually make because of this code remembering issue!And, just how many cars are being driven out there which have had codes erased and really have problems? This is a scam even Bill Clinton would be proud of.


#8

It sounds like someone in the shop didnt address the valve body during the overhaul. This is why they are telling you that they will try a new valve body. The P-1870 code means “Transmission component slipping” These transmissions are notorious for wearing out valve bodies. Most all of the time when this code comes up it has to do with the TCC regulator valve in the valve body. What happens is the steel tcc regulator valve wears out its valve bore causing ATF to pass by the valve which in turn lowers the apply pressure to the converter clutch and makes it slip. The harsh shifting is there because when the computer picks up a slip and sets a slip code it automatically maxes out the line pressure in the trans to protect it. This is such a common problem in these transmissions that the trans shop should have had this right the first time in.

transman


#9

Well I got the van worked on again today, he said he was waiting on a valve body and that he put “new seals” in - something you do whenever you break it down?. No extra charges, said all the work is under the warranty - good so far. The van drove ok back home and I got a list of the parts replaced.

Converter,Banner,Filter,band,shell,solenoid pack & shop supplies.

Would the valve body be the “solenoid pack”? I am still driving with an expired tag as I have to put enough miles on it for the “computer to reset” or whatever. Funny but when shifting between 1st & 2cd or the lowest gears it still hesitates a bit but does not make a clunk noise…yet, maybe that is just typical for the van.


#10

I am susceptible to conspiracy theories, extremely so when spending money on car repairs. The shop working on my van said they would “upload the updates” to my car computer [which I didn’t know existed]. That set me to wondering - could a place I previously had the van at or some scoundrel just jack in the wrong software for my transmission or is this all hardwired in the unit? I am theorizing the wrong software would guarantee bad shifting, good transmission or not. Ponder…Maybe that is how Clinton balanced the budget???

My van does have 184,000 miles on it however and everyone I spoke with gleefully explained that a “complete transmission overhaul” was the only solution at that age.