NMTB

I recently bought a 2001 silverado I am going to build a mud truck out of it. I an wanting to put a 400 turbo in it the 4l80e is dead. Does anybody know what all I will have to change to make this work. Will I have to have the computer flashed.

RandomHero

iTrader: (24)

Why not just rebuild the 4l80e? It's essentially the same transmission just without overdrive and the electronics.

L7 Sierra

Rebuild or aquire a used 4L80. You will want the OD to help you get home so you can gear it deeper if you want.

You can make a 400 work, but hooking up a ported vac would be hard and a kick down cable would be too. That or you have to run the truck with a manual valve body to make it work. Either way the 4L80 would be cheaper.

2005 Silverado

iTrader: (19)

From reading around the site, flexplate, converter, trans, lines,and driveshaft, not sure about crossmember setup, and you would have to have a custom trans tune made im pretty sure.

But 80e is strong, but way more expensive.

Dustin

RandomHero

iTrader: (24)

LOL, 4l80e parts are pretty cheap and he already has one. Granted TH400s are dirt cheap, but the swap parts will cost more than the trans will.

Dgrown

I can understand why going with the TH400 over the 4L80E but for this application it might be in your best interest to go to a reputable trans shop and tell them your plans and have a trans custom built

NMTB

The truck is a 2 wheel drive that I am going to make a 4 wheel drive out of it. I am going to run 2.5 ton front and rearends sodrive shafts will have to be made anyway.I just dont thank the 4l80e will hold and its cheaper to have the 400 built when it breaks.

Dgrown

the 4L80E is just the newer version on the TH400 if you going to be running that big of diffs i would possibly be looking into going with an Allison

TieRod

LOL we use internals from a 4l80e in 400s to make them stronger. Basically an 80e is a 400 with overdrive. 75% of the parts are interchangeable.