LoveOurGMTs

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Hey everyone I have a question about rebuilding the 2004-2006 4l60e, ive been debating on putting a performance kit/Alto rebuild kit mixed a little with sonnax to make it more durable, im just curious if anyone has done it and is it even worth it, the estimate that i made myself is 1800$, this is pretty much everything from the valve body parts to the clutch packs and sunshell, i know all the weak points i want to do but the question pretty much is, is it worth doing it to everything or just the crappy parts like sunshell for EX. or 3-4 clutch packs i already bought a sonnax upgradded servo/super hold.. but the truck is basically stock no hp upgrades yet but i do want a cam later down the line with ported heads, intake blah blah blah....
 

99Sierra2500

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Welcome! All that sounds good to make the 4L60E stronger. Nick on youtube I think is pretty knowledgeable.

 

Tonimus

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If I'm going through all that, I'm going with a 4L80E. Just do a segment swap on the PCM and send it. A cost effective but decent 4L80E rebuilt kit is about $300. Figure $1k for a 4L80 out of something, $300 for a rebuild kit, another $400 for a torque converter and you're at $1700. OBD2 adapter to do a segment swap on the PCM is $80. 4L60E to 4L80E adapter harness is $30-100 depending on the source.
 

stutaeng

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Another vote for a 4L80e swap as @Tonimus pointed out. I did that on my 99 Silverado ECSB 2wd while I swapped from a 4.3 to a 5.3. On my truck configuration, there's no need for a drisveshaft shortening because the 2 piece driveshaft frame mount crossmember has slots for the center carrier bearing.


LT1swap.com has information for repinning the case connector and adding the other speed sensor. A new sensor pigtail is like $15. You don't need the adapter and actually some of the adapters have had reported issues.

There's a special yoke that mates the 4L80e output shaft and uses your stock driveshaft u joint.

You'll also need to modify your transmission crossmember (or get an aftermarket one from ebay).

It sounds kinda like a PIA, but it's pretty straightforward and easy. 4x4 does add a complexity with the Tcase.

The good news is that after you swap a 4L80e, you can mash the skinny pedal all day long and that transmission is just gonna laugh at you! Lol
 

INW-Iron-Steel

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Hey everyone I have a question about rebuilding the 2004-2006 4l60e, ive been debating on putting a performance kit/Alto rebuild kit mixed a little with sonnax to make it more durable, im just curious if anyone has done it and is it even worth it, the estimate that i made myself is 1800$, this is pretty much everything from the valve body parts to the clutch packs and sunshell, i know all the weak points i want to do but the question pretty much is, is it worth doing it to everything or just the crappy parts like sunshell for EX. or 3-4 clutch packs i already bought a sonnax upgradded servo/super hold.. but the truck is basically stock no hp upgrades yet but i do want a cam later down the line with ported heads, intake blah blah blah....
I'd do everything. My philosophy is to build the strongest/best unit I can afford to build because I KNOW I will be hard on it. I told the shop who built mine that I fully intended to put a cammed 6.0 in the truck. They essentially built a 4l70 with some aftermarket extras. Stout unit, I've beat the snot out of it. Sonnax/Rostra parts are solid. I am a big fan of their pinless pistons and springs/shift kits. I own 4x4s exclusively, which makes the 4l80 swap a bit more difficult
 

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