5.3 4L80e swap into 5.7 with blown 4l60e on a 1999 2 door tahoe in decent shape

[JesseObs]

Hey all, I've recently picked up this blue and silver 1999 Chevy 2 door tahoe for 600 bucks on the fact that the transmission was destroyed and the engine hadn't ran in about a year and with some bargaining here I am, in the past I was planning on doing a 5.3/6.2 swap on another truck in town that turned would've been a real headache to even get to the point of doing an ls swap.... I digress I am curious if anyone has done this swap before because I've seen posts and threads about single aspects but all the stars haven't lined up, from what I've found at least. all that said I'm just curious about the wiring and mounting for the 4l80e with an engine that wasn't really meant to go there. And ideally I'd like to have all my gauges, especially with my last tranny swap in a vw golf leaving me speedometer-less.

 

[JesseObs]

I am planning top do a drive by cable throttle if that helps at all. Also I've seen wiring adapter kits for the 4l60 to 4l80 and was wondering if that would work. furthermore would the speedo work from a 4l60 transfer case or however the 60 gets its speed reading to the speedometer to an NP241 paired to the 4l80

 

[L31MaxExpress]

Hope you are planning a really loose converter and a re-gear in your future. 5.3L is boarderline gutless with a 4L60E much less a 4L80E. Some 03+ vans came with a 4.8L/4L80E and even with 4.10s running in an empty cargo van with the cruise set at 70 mph, those will double downshift to 2nd gear to hold 65 mph on even a slight uphill grade.

 

[stutaeng]

I drive an ECSB that I did a 4.3/4L60e to 5.3/4L80e. Engine/transmission is stock , but I really like that combination. It's a 99 NBS and 2wd though, so I can't help on the guages and transfer case on your truck.

But I did a thread on the swap and has useful information on the 4L80e swap here on this subforum. Tip: it's easier than you think and you really don't "need" the wiring adapter. The wiring is all there. You just have to repin the case plug and add the additional speed sensor. $15 or something like that.

Mine has 3.42 and I thought I was going to need to swap to 4.10, but honestly 3.42 are just fine. I run LT265/75/16 tires. I'm swapping an 9.5" K2XX axle that I regeared to 4.10, so I'm kinda stuck with 4.10s. 3.73 would be perfect for all-around driving if I had to do it again. A Tahoe is on the lighter end of the weights of these generation trucks, so you'll probably be okay on what gears you have.

Edit: get a junkyard 6.0 flexplate from a 2500HD. Or a ATP brand standard auto parts store flexplate replacement. Both will have the little 0.400" spacer. You can also use a 2500 '01 to '06 suburban 6.0 as truck look-up. Also get the longer bolts for the flexplate.

 

[JesseObs]

Hope you are planning a really loose converter and a re-gear in your future. 5.3L is boarderline gutless with a 4L60E much less a 4L80E. Some 03+ vans came with a 4.8L/4L80E and even with 4.10s running in an empty cargo van with the cruise set at 70 mph, those will double downshift to 2nd gear to hold 65 mph on even a slight uphill grade.

im sure ill do headers with bigger injectors at some point and ill take the re gear into consideration

 

[L31MaxExpress]

im sure ill do headers with bigger injectors at some point and ill take the re gear into consideration

If you are only adding headers there is no reason to upgrade injectors, unless you are running 99-00 injectors.