4l60e to 4l80e Conversion

tjmrider · Aug 10, 2020

Looking to upgrade the transmission due to buying a new boat. 4l60e will struggle, and be maxed out.. What goes into doing a swap like this? Is is reletively straight forward or do you have to buy a complete conversion kit (transmission adapter, tranny mount adapter, new wiring harness, tune, etc)

Rocket Man · Aug 10, 2020

Depends if you’re 4wd or not. If so you’ll need a transfer case adapter. Minimum is a torque converter, custom trans cross member but these can be bought, wiring harness, custom driveshaft and your tcm will need a segment swap tune. More info is available over at www.performancetrucks.net if you go there and search. There’s been one or two members here who have done it.

Foggy · Aug 10, 2020

There are companies that make a very stout 4L60E that will hold up to towing
and additional power.. It would be a lot easier and cheaper to stick with the
factory configuration due to the things RocketMan mentioned..
I have done this is my older C1500 due to my power level and towing, but
it was much easier as I am 2wd and use a stand alone computer/controller just for
the trans.
Try companies like PATC and such .. there are a few very reputable co's that
build very strong 4L60E's .. Make sure to run a high quality torque converter.

Remember, a stock 4l80e isn't perfect either.. You would want at least a
"stage 2" type build in the 80e

intheburbs · Aug 10, 2020

Seems like an unnecessary expense.

The 4L60 in my 2001 Suburban is still the original gearbox at 275k miles. I did a ton of heavy towing - trailers in the 6k-7k range, including the Rockies and the Continental Divide passes.

Now, what did break, multiple times, was the rear axle. It is currently on rear #4. I'd be more concerned about that than the transmission.

Simple rule of thumb with 4L60/80 - tow in 3rd. 3rd is a 1:1 ratio, so it puts zero stress on the transmission. Tow in overdrive and you're forcing all that power/torque through the weakest part of the transmission.

Rocket Man · Aug 10, 2020

Foggy said:
There are companies that make a very stout 4L60E that will hold up to towing
and additional power.. It would be a lot easier and cheaper to stick with the
factory configuration due to the things RocketMan mentioned..
I have done this is my older C1500 due to my power level and towing, but
it was much easier as I am 2wd and use a stand alone computer/controller just for
the trans.
Try companies like PATC and such .. there are a few very reputable co's that
build very strong 4L60E's .. Make sure to run a high quality torque converter.

Remember, a stock 4l80e isn't perfect either.. You would want at least a
"stage 2" type build in the 80e

Performabuilt is one such company. I have a Stage 3 in my 02 Denali with a supercharger and I have managed to f**k it up twice but they finally figured it out- I was using RTV on the pan gasket when I changed the filter at their 2000 mile break-in period which unknown to me is a no-no with a 4l60 because it clogged the servo passages up so they weren’t releasing which caused a super violent 1-2 shift. The last time it twisted the output shaft in half and they still covered it under warranty. I did have to ship it to them but all it cost me was shipping one way. They build them specifically for towing or in my case high hp. Their service is the best in the business. Www.performabuilt.com

4l60e to 4l80e Conversion

tjmrider

TYF Newbie

Rocket Man

Mark

Foggy

Full Access Member

intheburbs

Full Access Member

Rocket Man

Mark

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