L31/6L80e

[1998_K1500_Sub]

Here's another stupid thought:

Powertrains since the 1990s have employed engine torque management schemes. The 6L80E, which I have to assume was designed with engine torque management as a prerequisite, might not live a long and healthy life without it, i.e., when using PCS's TCM2650.

Anybody have any thoughts on this?

Are the friction disks going to get wiped clean in relatively short order because there's no engine torque reduction during the shifts?

Will clutch dust rapidly accumulate in the oil, and deposit in the oil passages and transmission internals?

 

[stutaeng]

This particular setup came out of an ambulance. 10 or 12 Dmax with a 6L90

Yes, they definitely did offer this setup, which I was not aware of. I recently saw en Express cab & chasis listed for sale with this option. I can't remember the year, but this seems correct.

 

[618 Syndicate]

Yes, they definitely did offer this setup, which I was not aware of. I recently saw en Express cab & chasis listed for sale with this option. I can't remember the year, but this seems correct.

Drove it yesterday! It's got a mild tune in it, pulls great.

 

[Jmbrad]

Well, my first official post here. As the title states, I am in the middle of swapping my 4L60e to a 6L80e, yes, behind the L31. I've done countless hours of research and contacting companies on how and what the swap would entail. Some of this swap is trial-by-error. I haven't really seen any forums/posts of folks swapping over to a modern transmission behind an older engine, but in fact, the reverse. I see threads on this site talking about a 6L80e swap, but with gen 3 and up engines. So...I figured I'd take you folks along my journey if you're interested. And yes, I do have the means of swapping an LS, and yes, I have argued with myself about how much of a waste of time this could be, etc... I don't need power as I have a Whipple'd 2014 Silverado, and a built 2010 Camaro SS. But I do like different. The goal is to keep it as simple and cheap as possible going this route.

Without boring you with my life story on where I started with this... I've got the 6L80e, modified the L31 torque converter (168 tooth), and just purchased the TCM-2650 from zerogravityperformance to talk to the TEHCM. One problem that I am very unsure of is the 6L80e torque converter's snout is too long, and thus I pose my question for help to you folks: The bolt pads are about an inch away from the flexplate. Keeping in mind I need at least 1/8" of play, would torque converter bolt spacers of that length mess with anything?

I've read through all 11 pages of this thread and am curious how the truck is running after a year? How's the mpg and performance?

 

[Erik the Awful]

I don't know if he follows the forum much, but last time I asked - probably about two months ago - he said it was running great.

 

[Supercharged111]

I don't know if he follows the forum much, but last time I asked - probably about two months ago - he said it was running great.

Give him a nudge, we want an update! I'm more interested in any quirks if there are any.

 

[SomeTahoe]

Once I get done tidying things up, I will compile everything into a single go-to post.

@97Centurion are things tidy enough for that write-up on the swap? This is very cool and there isn't much out there about such a thing.

 

[L31MaxExpress]

I like the idea. That being said the 6spds do not seem to live nearly as long as the 4L80Es do. Massive numbers of failures and they are expensive to rebuild when they break.

 

[Christian Steffen]

I like the idea. That being said the 6spds do not seem to live nearly as long as the 4L80Es do. Massive numbers of failures and they are expensive to rebuild when they break.

From what I understand, it's primarily due to a ****** torque converter and bad transmission tuning from the factory. On the 14+ 6l80s (haven't looked at older) they're tuned to slip the tcc 10-30 rpm when locked. They also unlock and relock every time they switch from v4 to v8, and some other stupid stuff.. tuned correctly I've heard they can hold good power.

But at the end of the the day 4l80 is king

 

[Supercharged111]

From what I understand, it's primarily due to a ****** torque converter and bad transmission tuning from the factory. On the 14+ 6l80s (haven't looked at older) they're tuned to slip the tcc 10-30 rpm when locked. They also unlock and relock every time they switch from v4 to v8, and some other stupid stuff.. tuned correctly I've heard they can hold good power.

But at the end of the the day 4l80 is king

I've heard the same. The 4L80 can overrun the previous gear with a sprag. The 6L80/90 has to release a clutch before applying another, 2nd can overrun 1st but after that it's clutch off/on.