While at the parts store I had them hook a scanner and it brought up this code. After internet searching I'm SO happy to learn it's a transmission slip. I've babied this damned truck since the day I bought it and it's been nothing but small problems. It does shift hard sometimes between 1st and 2nd. Is this definitely the TCC valve or could the solenoid be going bad? My transmission fluid is full whenever I check and it's nicely red and clear. I guess there's really no way of knowing until ohming out the solenoid. I'm not sure whether to bother with the a74741q upgrade valve before trying to sell as I've read it's really just a temporary fix. It's a shame because I really like how it looks, handles and drives but my word constantly dealing with issues is tiring. Meanwhile my eyesore '93 Escort wagon (that's really a Mazda) keeps chugging along with no annoying problems that this Blazer has been plagued with. I'm a Mazda convert which will be my replacement vehicle....I'm finished with domestics.

 

Not sure if it helps you, as every vehicle's history is different, but in my '96 I had the same code. To fix it I opted to just buy an upgraded valve-body with the upgraded solenoids, and after the repair I drove the truck for another 5 years without any other transmission problems. At the time I did not do a transmission flush because my transmission fluid looked good. I only changed out the filter and then topped up the transmission to replace the fluid dumped from the pan.

If you're having other problems with the truck then you'll have to take that into account when you decide whether to replace your truck or not.

 

Thanks for the advise. I wrote that pretty hot when I found out what the code meant. I originally thought it was my gas cap as when I bought this 2 years ago the new cap made the light go out-temporarily. Now I'm thinking it was totally unrelated and it's just getting worse as my light stays on all the time now. Hopefully I can find that upgrade valve spool locally and I'll go ahead and drain the fluid and change the filter while I have it out. Watched a video where the guy was able to remove the spool by grinding a set of needle nose down to fit the slot and get the retainer pin out. He did it without having to remove the entire valve body-how bad is it to remove? An automatic tranny is new territory for me. I'll ohm out the stock solenoid to make sure it's not the problem but it would be nice to upgrade it while I have the pan off. What is the solenoid upgrade?

Yes, I've had other problems but small ones. The 4x4 has never worked right, my front gearbox has a slow leak, and my passenger floorboard gets wet at random that I cannot find where it's getting in at.

 

Passenger floor, do you top up anti freeze often? Or on a scheduled basis

 

Dropping the transmission oil pan is a bit of a pain because there's no stock drain system, so you basically just have to loosen and remove all but 2 bolts, then carefully lower one corner and dump as much oil as you can. I had no experience with transmissions prior to doing the swap, but was able to do it with normal hand tools. Just be prepared for a mess. The upgraded valve body I bought came with great instructions that helped a lot. The valve body has several floating check bearings that you have to be careful to not lose, but other than that it just takes a little while.

 

P1870 Explained

 

I haven't had to ever put anti-freeze in. I think it's rain water. Removed the cowling, cleaned it up, replaced passenger door seal, condensate is draining fine. Just when I think it's stopped, it'll just get wet again and no, it's not anti-freeze.

 

Thanks for the link!

 

After looking online, I know I definitely need the TCC valve but should I go ahead and change the A and B shift solenoids along with the torque converter pulse width component? I'm on a budget and I think I'll get the upgrade tranny pan with drain plug that holds an additional 3 quarts of fluid.

 

Dropping the ATF pan on a 2 wheel drive Blazer is straight forward. On a 4 WD, other 4 WD machinery get in the way. One trick is to raise the trans a little to allow more clearance between the ATF pan and the trans cross member. Some suggest removing the cross member, but that is not necessary! Just loosen the two nuts on the rear trans mount and it will give you the ability to raise the trans. an inch or so. Don't go crazy on the lift. All you need is an inch or 1.5 ". I rec. a wooden board to cushion the jack head and the alum. trans while doing this procedure. Use caution and all standard safety procedures.