4l60E TCC slip problems, is there a way to tune it out

2003 Yukon Denali 6.0 with 4L65e, built with Beast sunshell, shift kit, alto frictions, Trailblazer converter. 3rd and 4th do not slip but the TCC slips once my tranny oil gets to the 170 degree range. Thats not hot by any means, but it is consistent. Under a partial load the TCC slips when cruising up a hill or under throttle, which makes the temp rise even more. TCC slip is 90 min 100max and I tried bumping up the EPC by turning the milliamps down after 150degree trans temps. Even if I lock it manually with diagnostics in scanner it still slips under a load. I know its a smaller converter but at some point trailblazers had to pull a load as heavy as my Denali is unloaded. This has been going on for about a year and surfaced about 4k after rebuild/reman converter install. Any ideas?

I had this EXACT same problem after trans fluid got above 150* F. Its a 4l60e in 1997 silverado 4x4.

It ended up being the TCC solenoid was leaking fluid past it when commanded ON once it got warm. The seam in the snout from manufacturing split and would close back up when it was cold.

Of course you'll have to change the whole wiring harness in the transmission to fix this as the TCC solenoid is the only solenoid in a 4l60e without a connector on it, that is its directly wired to the harness unlike the shift solenoids.

This is that little bastard.
https://m.imgur.com/gallery/wWkLiTG

I can't see your pic but I do know what solenoid you mean. They make a replacement that is aluminum by Sonnax with anti drainback valve, but it requires pump removal to insert an orifice cap..dont wanna pull the whole tranny if I dont have to. Maybe I will splice in a new OEM replacement. Thanks for the advice. Did it work fine and just slip under a load once hot with yours?

Yes its exactly what it did. At first it would only do it pulling a trailier down the highway in overdrive then it got to the point any time trans temp went above 150 i would loose lockup. Cold it worked fine.

And on mine it wouldn't even attempt to lockup after it got hot, slip RPM wouldnt change at all between locked and unlocked. The TCC valve actually controls your trans cooler flow which is your lube circuit for the planetary sets. So if that TCC valve isn't stroking all the way and gets stuck "in between" the lock and unlock circuits you lose all lube and cooler flow and the thing melts to the ground.

You dont have to pull the front pump to change the TCC solenoid or the TCC valve itself, just have to pull the pan. If you buy the internal wiring harness for a 4l60e it comes with the new TCC solenoid.

These danm 4l60s / 700-r4s are finicky with lockup. I have to ask is it throwing the dreaded p1870 trans component slip code?

Replaced both the lockup solenoid with the snout that goes into the pump and the pwm solenoid. It still slips. I was hopeful because I couldnt blow through the old one(black) and I could blow through the new one (white) with it deactivated, but maybe its an anti-drainback design or something. Found some black material in the pan, and some shiny aluminum particles but the trans still doesnt slip under WOT with converter unlocked or locked when cold. I assume this is from the rebuild as I put in new bushings and something has to wear somewhat when its tight. I also built my 3-4 stack pretty tight because I heard they spread after break-in, so maybe some material there. I honestly think maybe its the lockup clutch material though, which means the converter might be shot..but why does it lockup under 160 degrees fine?

No 1870 code btw. I have videos of it doing this if that helps.

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Originally Posted by 3strokeEngine

I had this EXACT same problem after trans fluid got above 150* F. Its a 4l60e in 1997 silverado 4x4.

It ended up being the TCC solenoid was leaking fluid past it when commanded ON once it got warm. The seam in the snout from manufacturing split and would close back up when it was cold.

Of course you'll have to change the whole wiring harness in the transmission to fix this as the TCC solenoid is the only solenoid in a 4l60e without a connector on it, that is its directly wired to the harness unlike the shift solenoids.

This is that little bastard.
https://m.imgur.com/gallery/wWkLiTG

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Exact same situation I'm in. Trans was rebuilt in my 2011 V8 ZQ8 Colorado to handle more. Got it back and after about 4 to 5 thousand miles, it started allowing the TCC to slip after 150?F fluid temp. 1 time it lost it completely for the last few miles home. I kept it in 3rd till I got home. I let the fluid cool and tried again. Worked fine. I'm only slightly concerned about the cooling circuit consideration, but not thinking I hurt anything there. What do you think a few miles of driving in 3rd would do vs letting it attempt to do a lockup and slipping all the way home.

Currently looking for a last gen harness with a blue and brown plug. Then I'll book some time at a shop that I trust.

TCC slip speed is zero in gears 2-8 when engine RPM is greater than 1600 RPM. Drive the vehicle while monitoring TCC slip speed. TCC slip speed should be 10 rpm or less also note if the shudder takes place during TCC apply.

Quote:

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Originally Posted by glozingclipclop

TCC slip speed is zero in gears 2-8 when engine RPM is greater than 1600 RPM. Drive the vehicle while monitoring TCC slip speed. TCC slip speed should be 10 rpm or less also note if the shudder takes place during TCC apply.

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Prove you are human: How many forward gears does a 4L60E transmission have?

Quote:

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Originally Posted by blindsquirrel

Prove you are human: How many forward gears does a 4L60E transmission have?

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Ha i had to laugh at this