Manual to auto swap

Hello,
I'm looking to swap my 2007 mustang gt from manual to auto. What is the easiest and most cost effective way to get this done. This car is primarily a strip car with occasional street cruises. Currently a full bolt on, cammed, 150 shot Lito tuned car with full built rear-end 35 spline axles, spool and 4:30 gears. Thank you, any help will be appreciated.

Hi Bruce,

I can tell you stay away from the 5R55. I put out about 500RWHP and have gone through the stock one and a beefed up one. I am currently putting in a Level 10 that should be good to 700HP. Fingers crossed !

If I was going to make that swap I would go with a purpose built turbo 400.

Bruce Tolliver said:

Hello,
I'm looking to swap my 2007 mustang gt from manual to auto. What is the easiest and most cost effective way to get this done.

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Just my opinion, the "easiest and most cost effective" is going to be to swap to a 4R70. GI Joe has an extensive write up on how to do it and everything you need here

KLJ777 said:

Hi Bruce,

I can tell you stay away from the 5R55. I am currently putting in a Level 10 that should be good to 700HP.

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I realize everybody's build and experience is different. But I have a fully built by Level 10 5R55 in mine, am around that rwhp, have beat on it like it owes me money for over 10 years, and it has never once given me any issue.

Midlife Crises said:

If I was going to make that swap I would go with a purpose built turbo 400.

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That would definitely be a good swap for a high horsepower track car. But given his description of his car I think it would be extreme overkill for his setup

If it's going to be as strip mostly car I would definitely just stay away from the 5R tranny. Going from manual to auto is kinda a pia unless you go with a stand along transmission controller. That way you don't have to mess with the stock ecu tuning, especially if your dragging the car. When we go to the track we put unusual loads and inputs into he car and if it's not tuned just right you can have issues. But back to the 5R tranny, I'm on my third, and my second was a Level 10 "Bulletproof" one that I fried the bands on. That could have been because I didn't have the 3rd gear upshift set with enough pressure but I have since had the Level 10 rebuilt locally with Kolene clutches. I wanna say the Alto Reds is what they used. I told the guy I drag the car and he still gave me his 30K mile warranty. It's been about 50K since and still going OK but I hardly race this car anymore.

I'm sure you're going to upgrade the input shaft of course but what convertor are you planning on?

After alot of reading I'm leaning towards the 4r70 swap. Thanks for all the help.

Why not just 6R80 swap the car?

Powerglide!

Anyone running 4:30 gears with a 4r70w?

Bruce Tolliver said:

Anyone running 4:30 gears with a 4r70w?

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Not the same I know but, I was running 4.30s with a T56 Magnum that has a 2.66 first gear. 1st gear was very short and the second gear shift came quickly after launch. I am trying 4.10s now.

white95 said:

Why not just 6R80 swap the car?

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Maybe I'm missing something but that sounds like more cost and PITA than it's worth on a 3V drag car. What advantage would a 6R80 have over a 4r70 with a steep rear gear (which the OP already has) in this situation?

AHaze said:

Maybe I'm missing something but that sounds like more cost and PITA than it's worth on a 3V drag car. What advantage would a 6R80 have over a 4r70 with a steep rear gear (which the OP already has) in this situation?

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None, I suppose, but rear gear changes aren’t hard.