If you were switching from a manual trans to an auto...

[ulev1st]

What would be your choice and why? HP level to the wheels will hopefully be in the 650 range..Thanks for your input.

 

[Hawgman]

Probably the 4r70w. Should be fine for the horsepower, one less gear but the final drive is about the same as the 5r55s, and it is less complicated. Although it would require a separate computer.

 

[tom281]

I am debating this very thing right now, although I'm just shy of 500 rwhp and don't plan to go any higher. I am leaning towards the 5r55 trans over the 4r70. From what I've read, a 4r built for power and with options, including a driveshaft, etc. will cost a pretty decent sized penny. Where as there seem to be many people running the 5r with decent amounts of power reliably.

 

[yzfone]

I converted to a Lentech 4R-70 from a manual, and I love it. You dont need a new computer if you set up 4th gear and convertor lock-up (if used) on a switch, otherwise yes you need something like a Baumanator.

 

[SC boss]

I am debating this very thing right now, although I'm just shy of 500 rwhp and don't plan to go any higher. I am leaning towards the 5r55 trans over the 4r70. From what I've read, a 4r built for power and with options, including a driveshaft, etc. will cost a pretty decent sized penny. Where as there seem to be many people running the 5r with decent amounts of power reliably.

I beleive the guys at Larry's Trans are takeing the stock 5R and doing a few mods and holding up to 600 safely! If you plan on staying 500 you should be fine as long as your line pressure isnt to high. And I still have a good tranny for sale!

 

[SC boss]

What would be your choice and why? HP level to the wheels will hopefully be in the 650 range..Thanks for your input.

I sure hope to reach and exceed your hp range and im going with the 4R70W! Better safe than sorry and I hear nothing but good things about the switchover.

 

[racevert]

I am running the Level 10 Stage III 5R55S tranny and it shifts great and holds up fine. I did not want to downgrade to a 4-speed auto or use a stand-alone computer. This way mine is a stock trans beefed up to handle higher power.
These 5r55s trannies (stock) are a crapshoot with anything over 425HP

 

[SC boss]

I am running the Level 10 Stage III 5R55S tranny and it shifts great and holds up fine. I did not want to downgrade to a 4-speed auto or use a stand-alone computer. This way mine is a stock trans beefed up to handle higher power.
These 5r55s trannies (stock) are a crapshoot with anything over 425HP

What kind of power are they rateing your stage III tranny for? Personal opinion but I wouldnt call a 4R70W swap a downgrade by no means. Yes you lose a gear but like Hawgman said final drive is about the same and you can hold alot of power for future upgrades with these trannys.

 

[Error404]

for a manual valve body (4R-70/W) with a converter switch, is any computer needed? I'm looking at doing this in the future.

 

[Born To Run]

Trans swap

No computer needed for manual to 4R70W auto.Len has rated & tested these trannys upto 900-1000 RWHP.He also holds 2 patents on the valve body,smart guy & a drag racer,give him a call,tell him Randy from Toronto sent ya.

 

[Ken3030]

I and others are happy with the trans built from Larry's Trans in Corona Ca. I know of 4 cars over 600 hp he built that are holding up. If you don't want to swap to the 4r70w give him a try.

 

[PenguinGT]

You're probably dead set on an auto, but for all the associated costs with upfitting for an auto, it'd be cheaper to go with a T56 6-spd. You know that can handle the power...

 

[boosted performance2]

TCI will have their built 5r55 out in about a month, saw it at PRI show

 

[MSgt46270]

I and others are happy with the trans built from Larry's Trans in Corona Ca. I know of 4 cars over 600 hp he built that are holding up. If you don't want to swap to the 4r70w give him a try.

Larry's Transmission has been good to me and my auto trans is doing great. Yes I had two codes the other day, but they are gone after talking to Tony and if I do have a problem he said to bring the car to him and he'll get it fix.

In fact, my son in the Air Force (in NoCal) has transmission problems (over Drive?) on his 03 Mach I and Larry's Transmission will be working on his car after Christmas.

Larry's Transmission is a great shop for trans work, great prices, and most of all honesty.

 

[SixtySix]

I wish I had or at least have heard about any good shops here in AZ. But at least Southern Ca, isn't that far away!