4L60E no 3rd or 4th
 

I just bought a 01 Blazer. It had just a drop of transmission fluid in it. It's slipping really bad into 3rd and has no 4th. Reverse, 1st, 2nd works great. It's throwing three codes as follows: P0741 - Torque Converter Clutch / Solenoid / Circuit Performance Or Stuck Off; P1870 - Trans Component Slipping ; P1870 , again. I'm changing 3-4 clutches and steel rings. Will this fix my problem or will I also have to change 2-4 bands?

Change the 3/4 clutches, but also replace the torque converter clutch solenoid. My .02

So no new bands? And I can leave the value body on because I'm not having to pull the pin, right?

It's called the 2-4 band cause it's only one big band and you'll be able to tell by looking at it if it should be replaced or not. If it is bad then you will need to replace the reverse input drum as well or your new band will not last. And if you put in a new band you will need to borrow a band pin length checking tool to make sure your pin is the right length. But since you have a p1870 code yes you will need to remove the valve body and either repair the tcc regulator valve bore with a sonnax setup or replace the valve body with a good one. It is also a good time to check for worn out checkball seats in the separator plate.

the 2-4 band is like 8-12 bucks I would change it, you will have to remove it anyway if your gonna rebuild the 3/4 clutches. pin is easy to remove, just use a magnet pops right out, take out the 2/4 servo also. I would get a 4L60E ATSG book if your considering doing this yourself.

sorry i know this is an old post but i am having the same problem and just wondering if you ever ended up getting it solved?and what it was u had done? ty