[imnprsd]

I have a 1997 Blazer 4/4 and every so often my tranny will shift hard, and then go away... if I restart my engine. Note: the SES light will remain on and no codes can be recovered. However, if I don't shut off the engine then the 1870 code is detected. So what's causing this?

The tranny seems to be working properly 99% of the time, and the Tranny shops (I talked with two) want me to drive it some more so that a "hard failure" can help them pin point the problem. Personally, that does not sound like a good idea to me.

However, now that I have read a few other threads... (this is a great site) I think my problem sounds like my TCC solenoid may be the culprit. Can someone tell me how to change out this part next week when I get my Tranny flushed properly!

NOTE 1: THIS PROBLEM STARTED WHEN I LET MY MECHANIC CHANGE TRANNY FLUID. He later told me he did not have the equipment to change the torque converter fluid. Then he sold me some JB Tranny stuff to see if that helps my shifting problem . It didn't work.

NOTE 2: I get the feeling the SES goes off more often when I drive long distances, so I also think this has something to do with the "lock out" feature I read in other Threads; however, I'm not sure how all this is related.

It would be great if someone can clarify for me what I can do cheaply to possibly fix my hard shifting problem which is intermittent at best.

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Here's a good comment, which I took from another thread, that seems to describe my problem:

a) A low input TPS code (P0122) will set off an intermittent SES light. This will inhibit TCC lock-up on the transmission, which will give you the P1870 code, excessive component slipping - the TCC. The computer will then, by default, set maximum line pressure for the transmission, which will most likely give you the hard 1-2 shift. The P1870 will also inhibit fourth gear from applying.

Yup, check connections, at computer and at the TPS. If you know how to check the TPS with a voltmeter, that would be a good idea, but it most likely needs to be replaced. Clear codes, take it for a spin and see what happens. Tranny flush is a good idea, fluid and filter.


Question 1 : Where is the TCC Solenoid? Is something a fluids shop like Jiffy Lube can do. They seem to have the right tranny flush equipment in my area.

Question 2: Do I need to get that JB Transmission additive out of my Tranny ASAP or is it a good additive? (Personally, I have use Lucas oil additives and I find them to be a good product. BTW, Lucas makes a Tranny additive... Any comments on using it?)