2001 Sierra Transmission Problem

[egrison]

I have a 2001 Sierra Ext 4x4 4.8L My transmission is slipping. Code P1870.

The truck has around 100,000 Kilometers. I replaced the trany fluid and filter, the fluid was dirty and smelt burnt. The bottom of the pan was dirty and had some metal shavings. The transmission works intermittantly, the slipping occurs when it shifts from 2nd to 3rd and sometimes it will not shift to 3rd at all. Also how do I find out what model of transmission is installed on my truck. I can't find any markings on the trany.

Any suggestions would be greatly appreciated.

[txab]

4L60E I believe. Sounds like it's time to visit a trans shop.

[bill190]

As to the factory installed transmission (assuming no previous owner switched it), you could take your VIN to a GM dealer parts counter and they should be able to tell you what transmission you have.

 

They can also give you a printout of the "RPO codes" for everything on the vehicle. Basically all options you have.

 

This comes in handy when you go to an auto parts counter for a part and they start asking a bunch of questions:

 

What engine? Ummmm???

What transmission? Ummmmm???

Gear ratio? Ummmmm???

Etc.

[Grip72]

let me know how this goes for you

 

i just took my 2000 sierra in to GM for a diagnostic last week with similar problems. it randomly shifts rough from 1st to 2nd and not quite as bad from 2nd to 3rd, had the p1870 code as well. the service writer said the tech said my tranny will need replacing the valve body needs replacing and the torque convertor isn't working problem. it's not locking up or whatever

 

i'm not impressed lol, i think i'll take it to a trans shop next week...gonna be expensive!

[Jsdirt]

2000 GMC Jimmy had the same issue & it was just the 1-2 shift solenoid (would start out in 3rd gear & just slip up to speed).

 

Very easy fix. Get a printout from dealer fiche to identify the 1-2 from the 3-4 solenoids (identical). Just drop the pan, unplug wires, pull out & install new. Cost about $25

[gmtech4]

i disagree with jsdirt ,you have a cooked 3-4 clutch,it can be fixed by only replacing the 3-4 fibers and steel plates and a pump gasket and an quick R & R ,or go for the full rebuild ,very common ,dealer tranny guys do them in their sleep ,I know I have lol

 

another option is a GM rebuild ,it comes with a very nice 3 yr 80 k KM warranty ,if you are keeping the truck ,it is somthing to concider ,