97 Transport: Transmission (P1870) Problems

1997 Pontiac Transport with 185,000 miles.
A month or so back, I started getting a 2-3 second squeel that sounded like a slipping belt that eventually engaged at the end of the 2-3
second squeel. I noticed the power steering was dripping onto the Serpentine belt and dismissed the problem as a slipping belt. Then on a subsequent trip down to South Carolina, the Service Engine Soon (SES) light appeared and the tranmission would no longer lock up the torque converter.
Autozone found two (2) error codes, both of which were P1870.
After surfing the web last night I found a bunch of info on the P1870 that had to do with slipping Torque Converter Clutch (TCC) problems. Most of the posts had to do with Chevy Trucks, not minivans. It appears that GM replaced cast iron their valve body with Aluminum and suffered loss of wear resistance. Apparently the valve gets worn and fails to generate proper pressure to the TCC, and causes it to slip. Last evening I pulled the PowerTrain Control Module (PCM) fuse in effort to clear the code. This didn't work, but this morning I once again experienced the 2-3 second squeel as the TCC tried to engage.
I have called the Transmission shop and they are quoting prices from $800 to $2000. I am about ready to sell the minivan for $2000-2500; hence, this sort of investment seems foolish.
Questions: 1) Is the TCC probably toast? 2) If I replace the Torque converter ($119 at Autozone) will I also be replacing the TCC? 3) How much of an effort is it to replace the torque converter on a 97 transport? Do I have to remove the tranny onto a bench? 4) For the valve body, I see there are several companies that make a "Bore & Sleeve Kit." Anyone have experience with this kit? What special tools are required? How much of an effort to get the valve body out so it can be bored and resleeved? 5) Is there any wisdom in rebuilding the valve body first and then replacing the torque converter only if the problem persists? (Does it make far more sense to replace both while I'm elbow deep in the tranny? (remember, I am going to resell this soon and I want to be honest as to what I have repaired)
Thanks in advance. Justin Koch
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1. Your torque converter clutch is probably fine. 2. The torque converter includes the clutch. 3. Yes, you must remove the trans, and then swap converters. 4. I have no experience with the bore and sleeve kit. 5. In my experience, this problem has been the valve body or a shift solenoid. I'd be tempted to replace the valve body and all solenoids to avoid a large amount of labor for a $20 solenoid later.
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This problem is common throughout the aluminum valve bdies, the torque convertor is not the problem, it is the worn TCC valve body bore. The kit will fix this, but it really isn't a "dyer" job. Big yes to number 5!

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Firstly, thanks for the feedback thus far. These newsgroups are terrific.
When I spoke with the Tranny guy yesterday, he mentioned that the P1870 did not prevent the TCC from trying to lock up. I have put well over 1000 miles since I had the problem and I just wonder if the TCC has been slipping this whole time.
If so, I am surprised by everyone's confidence that the TCC is still fine. I plan to change the Tranny fluid this weekend. If it is clean then I will join you in believing the TCC is fine. IF there is bunches of junk, then it will be another story I presume.
Also, I have no clue where the valve body is located. Do I have to remove the Tranny to get to this or is it accessable once I remove the Pan? I have a Haynes manual at home, but have not looked into this yet.
Lastly, does anyone know the tranny number that is used for the Pontiac Transport/Montana for 1997?
TIA, Justin Koch

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It's inside the side cover. You must remove the subframe or lower the left side and then tilt the engine/trans to allow enough access to get the cover off the side. I recommend you don't try it without a lift.
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