terravast4

iTrader: (25)

I am getting ready to make a 4L80 swap and have heard from a lot of people that due to the gearing in the 4L80 it is kind of sluggish off idle. Can those of you who made the swap chime in on this? Has anyone changed the rear gearing to compensate for this?

firebladeJJ

iTrader: (1)

I havent done the 4l80 swap but I was in the same boat with the t56, much lower gear ratio with the 2.66 first, i did 4.56 but i also have 2 more gears and a .50 od. The 4l80 first gear is like 2.48 or some thing. my nieghbor years ago did his, he changed to a 4.10 like the HD trucks, he was pretty happy with it. All so take in to account how tall your tires are.

terravast4

iTrader: (25)

[QUOTE=firebladeJJ;5478893]I havent done the 4l80 swap but I was in the same boat with the t56, much lower gear ratio with the 2.66 first, i did 4.56 but i also have 2 more gears and a .50 od. The 4l80 first gear is like 2.48 or some thing. my nieghbor years ago did his, he changed to a 4.10 like the HD trucks, he was pretty happy with it. All so take in to account how tall your tires are.[/QUOTE

was the gear swap and trans done at the same time or did you swap the trans and feel a difference then swap the gears to compensate?

firebladeJJ

iTrader: (1)

I did them at the same time, i created a spreadsheet in excel that would calculate the MPH at the desired RPM in any given gear with editable rear ratios and tire sizes, used that a bunch to look at how my truck would drive with various tire sizes and rear gears. if i had left the stock 3.73 gears in there with the 2.66 first gear, top end of first gear would be around 60mph, i wanted it to be around 40 or 45, 6th with the 3.73 would have been useless, running 80 just a hair above idle. not good for high way cruising.
with a 32" tire and the 4.56, first runs up to about 45 and gets there quick, also in 6th I'm running down the highway at 80 around 2k rpm.

madmann26

iTrader: (7)

I run 3.90s and a loose converter and honestly I like it better.

1st to 53mph. Lol

terravast4

iTrader: (25)

Thanks for the comments

vmaxpro

When I do the 80e swap which seems to be the only option, Im going 5.13 gears. However, thats with a 14 bolt and 9.25 up front and 36” tires

terravast4

iTrader: (25)

I am running a 28.6” rear tire. Considering a 4.56 rear gear to make up for the 4L80 and get a better 60 ft time

madmann26

iTrader: (7)

Don’t. The gearing isn’t as bad as folks say.

4.56s are fun but on the highway you’ll turn about 3500rpm at 80. That suuuuuuucks.

I used to have them. I swapped to 3.90s as a split between the 4’series and 3.73s.

1994Vmax

iTrader: (4)

The gearing in the 4L80e is absolute dog ****... same as a turbo 400. It's fine in something light enough with a bunch of power but anything else it's a turd. Regular cab short box with short rubber will be okay... but running 4.56 will basically be like my Nova with 4.10 and a turbo 400 and it's useless on the highway. It's not a street car though so I don't really care.