7.4L 4L80e Locked During Shifts

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andy396

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For anyone that has a L29 custom tuned, has anyone had the guts to try enabling the TCC to remain locked during a shift?

I know it is enabled in the GMT800 trucks but that’s only with a 6.0/4L80 combo. I’m guessing GM left it disabled on the 7.4’s to prevent shock overloading the trans?

I really want to try it but I’m skeered [emoji51]

It’s probably fine for part throttle shifts, but I’m worried the first full throttle shift I do I’m going to kiss my input shaft bye bye.

What’s your experience and/or thoughts?
 

L31MaxExpress

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For anyone that has a L29 custom tuned, has anyone had the guts to try enabling the TCC to remain locked during a shift?

I know it is enabled in the GMT800 trucks but that’s only with a 6.0/4L80 combo. I’m guessing GM left it disabled on the 7.4’s to prevent shock overloading the trans?

I really want to try it but I’m skeered [emoji51]

It’s probably fine for part throttle shifts, but I’m worried the first full throttle shift I do I’m going to kiss my input shaft bye bye.

What’s your experience and/or thoughts?

8.1 and Duramax vans stay locked during shifting. Also the 01+ 0411 5.7 Vans do. Even the 60E locked up in 2nd at WOT on the 5.7 van tune I used when I still had the 4L60E.
 

Mangonesailor

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Hell, I know the bronco with the E4OD trans goes 1, 2, 3, TCC locked, 4th when shifting. When you click off the OD the TCC stays locked.

I'll say I don't like how much it bangs into the next gear. I'd prefer it to unlock, shift, and relock ASAP.
 
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