Hello, I have a 98 blazer, 4L60E, deep pan, with 143k and no rebuilds (engine or tranny)
For some time I have delt with the P1870 Code, but I just kept her in town on light duty (groceries).
I recently found out about teckpacks tcc valve fix, TCC VALVE from Teckpak / Fitzall and went ahead and got it.

Now I have installed it accordingly, properly, and with a new trans filter and fluid. I believe it is in "limp home mode" now. I am not sure why. After the fix, I drove it around the block and it never shifted, just rev's out searching for a shift. reverse works fine, but D-1st is all the same and Very sluggish, possibly locked in 3rd?

I am wondering if anyone else has tried this fix and gotten simular results, or knowledge of why. Also, I believe there is a way of pegging the tcc valce in place rather than replacing it, which i think works with the same principals as the new valve I have put in.

Do i need to get a new PCW-TCC? Shift solaniod? I am trying to avoid replacing the valve body with the updated one, and replacing the transmission.

 

I put in a drain plug, and its putting pressure on the filter. the pan was leaking so I've drained it. I'm going to move the drain plug out of the way, get another filter and gasket, and get fluids back in there. Any ideas while I'm back in there?

 

My only excuse is that it was freezing cold outside. I forgot to put the retaining clip back on the pcm-tcc, so that was most likely the problem, gonna button her back up and see what happens.

 

Transmission seams to shift fine, but the real test will be when I can heat it up. As for now I've been fixing stripped out threads, chasing a leak from the pan, and customized my shift cable bracket for better access to that one bolt, I'm sure I'm not the only guy that hates it. I put fluids back in her tomorrow. Assuming it doesn't leak I'll post back on the TCC fix. For now I just hope it doesn't leak....

 

To finish this one sided conversation that I hope helps someone:
Leak is fixed. That being said I got her up on the road and did some freeway driving, after some back roads, to heat the tranny up best I could, and then back into town for some stop and go.

It did not give me the 1-2 hard shift.

Now my tranny is old and will need to be replaced sometime, but if you catch it in time, Id say try the TCC VALVE from Teckpak / Fitzall. I drove mine for far, far too long with its issues, and this still locked things back up, for now.

 

Nice job! When mine went I ended up replacing the whole valve body with a rebuilt one and that worked great too. The guy I got mine from even sent me all the gaskets with a new flex plate and a diagram so I could locate all the check ***** in the right position. I bet I paid more but I ended up putting another 90,000 km on the tranny before the torque converter main bearing came apart and barfed metal into the trans and killed it.

 

I did the same thing with replacing the valve body with a rebuilt one to solve the P1870 and hard 1-2 shift when warm. Cost me less than $100 including gaskets, a new filter, and fluid. My Blazer is still going strong 4 1/2 years later, and is my daily driver.

I'm glad you figured out your problems and hopefully it drives great for a long time now!