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Discussion Starter · #1 · (Edited)
I searched, plus poked around the stickies and there's a lot of stuff on TCs!​

I got a problem that's either gonna be real simple to diagnose, or I'll start doing the readings to track down my current lockup problem.​

The setup:
-Normal motor and a good tunejob
-I rebuilt the tranny all the best stuff and a 3000 Edge 4 years ago = maybe 12,000miles on it all.​

Current State:
-Last year when REAL hot outside I noticed the car ran hot on the interstate and lockup would kick out and a CEL would come on after running 1-1 1/2 hours at 75. Turned out the light was P1870.
-So, I replace thermostat. A Dealer friend says his decision-tree book says it's plugged cats. They supposedly overheat the car and cause the lockup to kick out.
-So, good excuse to get Tri-Ys and cats and new AC O2s last year.
-This year the car's doing fine but been getting P1870 light even around town - but it resets itself every 5th trip out or so.
-This weekend (with light off) it's real cool outside, the car never even gets to 1/4 on the temp gauge, but I lose lockup and get a new light again after 1/2 hour on the hiway. It happens again like clockwork coming home. The light's still on starting out but lockup is fine until pulling a grade at 1/2 hour, and then no more lockup after that.​

So, it ain't temp related. And, what's so magic about exactly a 1/2 hour running at 75? Andre is stumped too. This garage queen ain't exactly getting pushed anywhere near the TC's limits.​

Like I said it's either real obvious for you guys or I'll have to just tear into it.​
 

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I'm in the same boat

I have a 96 Caprice that is mildly modded with bolt-ons and just had the trans rebuilt this past May, with 132K miles on it. The trans has had a 3200 Edge in it for the past two years, and it has been raced in the SEIRS. The trans broke the sunshell while driving it back a forth to work, which is a 30 mile commute. After having it rebuilt with all good parts and a Trans-Go shift kit, it performed fine for about 3 months. One day while driving home from work, up a very slight grade, the trans went into "Limp" mode, dropping out of lockup and the check engine light came on. Upon stopping and starting, it started in 2nd gear. I stopped, turn off the engine and restarted, and it performed fine other than the CE light still on. Had the code checked and it was an 1870, trans problem. Had a new TC lockup solenoid installed, thought it was fixed, and it just did it again coming home tonight. During one of these episodes, I changed the PCM, as that was mentioned as the culprit on some of the forums for Chevy trucks with the same trans. The second PCM was in it tonight when it acted up again.

Sorry for the long description, but I'm at a loss also. The shop I am using now wants to install a new valve in the valve body after boring it out and putting a sleeve in to take up the possible loose play. Sounds good, but so did the solenoid replacement.

Thanks in advance for your help.
 

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Discussion Starter · #3 ·
Well darn. It appears we're just two Bob's all on our own here eh. :( No one is throwing in so I have a thought or two. I trust you took advantage of going over the big stickie and a little search-ing.

You mentioned losing lockup and getting a 1890 code, which for all I can tell is basically the computer saying "hey fella something is slipping in your transmission but we don't know what". I didn't think that equated to an official 'limp mode' as you stated however, which is when the computer loses touch with the transmission. The only difference between us is I'm not losing 1st like you.

You mentioned a sleeve repair and I'm not certain this is a magic pill but it's worth looking into as an alternate to what you already mentioned.
http://stores.ebay.com/CT-POWERTRAI...h&LH_TitleDesc=1&_fsub=12564917&_sid=79392277


For my case, there's good stuff on the code in search in this section but nothing hits the "lose lockup like clockwork even when it's not overheated" like I am getting now. You mentioned truck forums and I suppose you found this:
http://www.gm-trucks.com/forums/index.php?showtopic=100760


I'm gonna get the line pressure gauge off e-bay and collect hints from watching it while I drive.
Bob M to Bob D out for now.
 

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Bob, I wouldn't buy that kit you referenced. Honestly that looks like throwing parts at it, since most of those will not directly impact lockup.

I'm assuming that both of you either installed the TransGo HD2C kit's mod parts to the TCC valve or staked it into the full-open position, so that shouldn't be an issue. How many miles are on the torque converter? The other thing I'd do is contact Pro-Built Automatics or Carolina Performance Transmissions and see if they have any suggestions.
 

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Discussion Starter · #5 ·
Thanks Joel. I'm with you on not throwing parts in without knowing what the problem is first. I recall the 'stake' and 'TransGo spring' Methods to curing the code from this thread;

http://www.impalassforum.com/vBulletin/showthread.php?t=227225

When rebuilding my transmission 5 years ago I reused all the parts from the 'Full' TransGo kit I installed around 2000. I honestly don't know if a kit that old had the fixer binding spring. I sure don't remember whether I did the stake procedure. If the procedure is not in the FSM or ASTG Manuals I probably didn't.

Before dropping the pan I figure I should get the gauge and collect readings to help with legit diagnosis instead of guessing.
 

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Discussion Starter · #6 ·

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The kit that Edge uses to build their converters are made with a small diameter
front wheel drive converter cores
which are not designed to hold a 4000 lb car.
Lock-up clutch will wear out quickly b/c its too small

Nab
 

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The kit that Edge uses to build their converters are made with a small diameter
front wheel drive converter cores
which are not designed to hold a 4000 lb car.
Lock-up clutch will wear out quickly b/c its too small

Nab
That is what I was thinking. Expect this problem to return.

Also, while I am by no means a 4L60 expert, I do not like the "stake TCC valve wide open" method.

PS. This thread originally posted in 2010!??!?!! I'm glad you finally sorted this out!
 

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Discussion Starter · #9 ·
..... 2010!??!?!!
hahaha Yep, but it didn't graduate from sporadic nuisance to permanent malady until maybe 1 1/2 years back and I don't get it out much. I eventually found TransGo instructions showing I had done the TCC valve mod after all so that was not the problem getting the code. It must have been the strange gray iridescent looking fluid that came out. I'm going to be more abusive to it for awhile. It'll either hit failure mode, or turn out fine from here on.
 

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I just did a full tranny fluid flush per this thread:

http://www.impalassforum.com/vBulle...-how-flush-your-4l60e-transmission-fluid.html

My nagging code is no more! And consistent lockup is back. So, add this to all the hints above and items listed in the TSB for this code.
the fluid exchange method is you drop pan replace filter. fill up the tranny with 4 qts. then disconnect the cooler line. start engine as 1 qt comes out add one qt. continue until the fluid is clean . using a gallon jug with qt level marks . add 1 qt when one comes out .

my guess total of about 12 qts should do it.

when its looking good suck out any excess fluid on level ground after you run it a bit so the fluid is normal hot just below the full mark never above fill mark.

if you had Dexron III in it and it got over heated that would cause this type fluid to cause slippage and the lock up will be shutdown.
 
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