What is the strongest automatic transmission to run behind a 4.6L I need something that can handle 500 to 700 hp, (depending on boost). Any direction would be appreciated. Thank you!

 

5r55s from Level 10.

 

The best bet for those power levels is doing a swap to a built 4R70W trans. The 5R55S can be built to hold about 600 max after that its just a matter of time until it breaks. The builders are advertising bigger hp numbers for the 5R55 but in reality the trans just doesn't have the internal capability to hold big power no matter how it's built.

In the long run you will be better off to just do the swap rather than try and get the 5R55 to hold up with big power. I know I wish I had gone that route. I have a built 5R55 in mine and I know I will eventually have to go with the swap.


Earl

 

Im happy with my built 5R55S. At retains five speeds and it is controlled by the PCM. If you go 4R70W you need a seperate controller or manual valve body.
I also have a fox body with a built Lentech AOD and I wanted to keep the factory tranny in this car.

 

I'd say the strongest is probably the 3-speed going in modaddict's 1000+whp turbo build...

 

I'm really flirting with the idea of putting in an automatic if my stocker explodes. I like the strength of the 4r70w but don't want a manual valve body. I would like an OEM looking shifter with the drivability of the stock tranny.


How often do you go to the track?

Have you had any issues?

Can discuss about how much the tranny costs?

 

TCI makes a good automatic transmission for the S197. We run them in several of our track cars.

 

At 700, none of the rebuilt 5r55's out there are going to hold up for any length of time. You need a 4r70 or TH400 IMO.

They make a full electric 4r70 so you don't have to have a manual valve body or trans brake if you didn't want one.

 

[QUOTE=modaddict;6172614]At 700, none of the rebuilt 5r55's out there are going to hold up for any length of time. You need a 4r70 or TH400 IMO.

They make a full electric 4r70 so you don't have to have a manual valve body or trans brake if you didn't want one.[/QUOTE]

That's awesome. I see one coming to me in the future.

 

You just use a Bauman controller or the likes. You cant control the 4R70W with your PCM though.
I have around 525 RWHP and my Level 10 tranny works for that power level just fine. I have no interest in going to a 4-speed 4R70W or 4R75W. However if you are planning on going over 650 RWHP the 4R trannies would be a good solution.