what tranny should i go with for turbo ls build

[69trk]

should i go with a 4l80e, or a turbo 400 with 3:23 gears?

[BR3W CITY]

the 4l80e is going to give you the same level of strength, with the bonus of overdrive and computer control (and if you'r running an ls, its almost easier just to run the o/d trans).

4l80e
1 2 3 4 R
2.48 1.48 1.00 0.75 2.07


thm400
First Gear - 2.48 to 1.00
Second Gear - 1.48 to 1.00
Third Gear - 1.00 to 1.00
Reverse - 2.07 to 1.00

essentially the same gearing.
you can run a higher rear gear to pep it up, and let the o/d keep the rev's down on the highway.

with 3:23 rear end you would be smooth as a caddy on the freeway with a 4l80e

what rear end are you running? The 3;23 was much less common in truck.

[Clyde65]

What BR3W said!

[69trk]

thanks, 4l80e it is!!! The rearend that i have now is truck 12bolt with moser 33spline axles and a full spool and 3:73's.

[69trk]

Originally Posted by BR3W CITY

the 4l80e is going to give you the same level of strength, with the bonus of overdrive and computer control (and if you'r running an ls, its almost easier just to run the o/d trans).

4l80e
1 2 3 4 R
2.48 1.48 1.00 0.75 2.07


thm400
First Gear - 2.48 to 1.00
Second Gear - 1.48 to 1.00
Third Gear - 1.00 to 1.00
Reverse - 2.07 to 1.00

essentially the same gearing.
you can run a higher rear gear to pep it up, and let the o/d keep the rev's down on the highway.

with 3:23 rear end you would be smooth as a caddy on the freeway with a 4l80e

what rear end are you running? The 3;23 was much less common in truck.

Where did you get your 4l80?

[BR3W CITY]

Originally Posted by 69trk

thanks, 4l80e it is!!! The rearend that i have now is truck 12bolt with moser 33spline axles and a full spool and 3:73's.

same exact setup as me! 5 lug truck 12 bolt with mosers and 3:73 nice.


I got my 4l80e off of craigslist. I found a kid who stripped cars in his backyard and JUST found a 96 2wd 2500 truck that he was selling for parts. I offered him $300 for the running trans and picked it up later that day. The price wasn't bad even if it ended up being a core, but it worked. I had her built anyway tho.

[69trk]

how much do you have in the build of your trans? How did you get speedometer to work? thanks

[69trk]

I found a 4l80e trans for $80. I plan on rebuilding to handle the power. My question is that this trans came out of a box truck with a drum mounted on the tailshaft. Will this trans still work? thanks

[usmcchevy]

$80! I don't care what it is, it would be mine Coming out of a box truck though, I think it may be a 4L85E with straight cut planetary gears....noisy.

[69trk]

it has a stamping on it that says it's a 4l80e

[BR3W CITY]

is the drum for a pto or something? no idea what thats about.
For $80 at worst you'd have to swap out the tailshaft, no biggie if your already gonna build the trans up.

I had my trans built with all new insides,seals, springs etc and a hd lockup converter (28 or 3200 rpm I can't remember) for about $1500ish.
The converter was actually spec'd based on future nitrous use, but I might not actually go that direction. I was told in conversation that the setup should be good to close to 800hp without grenading.