My 4R70w Conversion

2bscrewed

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I finally got rid of the 6 speed and went automatic since the stick and turbos didn't really get along that well from a dig. I decided to go with the 4R70W because my car is primarily a street car that I drive to work whenever it's nice outside and it's not broke. I have a 35 mile highway trip to work one way, so OD was necessary.

I won't go into great detail about everything, since we already have a great article by Dave King on the web to use, but I figured I would post up how I did mine.

I sold my complete Magnum, Mcleod, drive shaft set up for $2700, which in hind sight was not enough since it all had very little miles on it. But it was a good start to funding the auto swap. After talking to FB, LenTech, and BC Automotive, I ended up Going with Darrin at BC. Between Price and the fact that he was willing to talk to me at length anytime I called, he made it an easy decision.

Out with the Magnum set up. (sorry for the crappy cell phone pics, I always forget the good camera when I'm working on the car)

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Once everything was removed, the first thing I did was make a plate from steel to cove the hole in the tunnel that the stick used to run through. I used the existing bolts, and holes, then sealed it up with the pretty orange RTV I had lying around. haha

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Took a little modifying to make it fit in the stock location, but it worked out pretty decent. I over trimmed the bezel a bit, and still have to stitch up the boot, but it should look pretty decent when it's done. I'm a tall guy with long arms, so moving the shifter back on the console was not really an option for me.

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The transmission came with a Billet triple disc converter from Circle D. I wanted it to be able to foot brake to at least 3k rpm, but the one I got was pretty tight and only foot brakes to 2200 rpm. I can only build about 2.5#'s down there, so it's a big turd from a stop until I get it restalled.

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The tranny bolted into place with no issues, but I did forget to put the dip stick tube in first, and that was kind of a pain in the ass to put in after the fact, even with stock exhaust manifolds. The passenger O2 sensor on the Hellion kit also sits right where the dip stick goes, so some serious prying was needed to get it back in also.

The custom Drive shaft was sourced from Shaftmasters for a great price with 3550 billet yoke, and I also purchased a Billet pinion yoke from the Driveshaft shop to make the drive shaft set up as strong as possible.

Next since I was using the Hurst Quarter Stick, I had to remove the factory shift lever and replace it with a B+M kit for the AOD's. Just had to drop the pan and take a couple things loose and pull it out and swap it., then had to modify the bracket that holds the cable to the pan, but no big deal with a friend and his welder. One note, if you ever use this piece, you do have to tap and plug the center of the pin, or it will leak. I didn't know this till after i installed it, so I just used some epoxy to fill it in, as there is no pressure behind it, just a weep hole leak.

Once that was done, I wired everything up. Since I'm using a full manual valve body, I stuck with the T-56 harness, and spliced the Auto speed sensor to the harness. My shifter has a neutral safety switch, so the only other thing I needed to worry about was the reverse lights. I still haven't wired them up, but I may just put them on a switch if no one has an easier way to do it.
The valve body wiring was pretty simple as you just hook 2 wires to 12V, and the other two to a ground source for OD and Lock up activation. Those are the two switches you see next to my tranny temp gauge in my shifter pic. I also ran the tranny temp gauge up with the valve body wires.

Next I mounted the tranny cooler that Darrin sent with the tranny. It is made by Be cool, and is big as hell. So I didn't really have many options on where to put it. I ended up putting it under the radiator support towards the front of the car. I didn't like the barb and push on fittings that came with the cooler, so I made some braided teflon lines for it.

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After getting everything buttoned up I took it for a test drive. It shifts really crisp and slow parking lot speeds are much easier and smoother now with no bucking. Once I got it up to speed to test the OD it worked great, but when I tried to use L/U, nothing happened. I tested all my wiring, and was getting 12V through the circuit, so I called Darrin up and told him what was going on. He had me swap wiring with the OD switch and try that, but still no luck. So the next day he sent me a new solenoid for the L/U. I was a little nervous as I know nothing about the internals of an auto tranny, but he said it was super easy, and to call him if I had any questions. So I dropped the pan.

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It really couldn't have been any easier. Drop the pan, and there it sits right below the two shift solenoids. Two bolts and it was out. Put it all back together and went for the test drive. L/U now works! I really thought it was gonna be more of a headache.

After driving it around for a week or so, I'm pretty impressed with how cool the cooler keeps the tranny fluid. I have the sensor in the pan, and the highest temps I've seen so far were 165.

I threw it on the dyno to see how much internet power I lost on my pump/meth tune with the auto in there now. I did this when I was waiting for the L/U solenoid, so I wasn't able to lock it up on the dyno. This tune made 850 SAE with the magnum in the car. We didn't change the tune at all, and for some reason the AFR nose dived to below 10.0 once boost hit. I watched my in car AFR gauge and never saw it go below 10.0, so I don't know if the Dyno gauge was off or what.

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So far I haven't really beat on it too much until I know for sure what the fuel is doing, but I know once boost hits in first, it's pretty ridiculous, and the car feels waaay faster. Hopefully when I take it to the track this fall, 9's in full street rim won't be an issue. I also got 18 MPG with 3.73's on my first tank of gas with the auto in, granted it was mostly highway miles.
 

Parts-is-Parts

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I hope the trans works out. Many reports of failures are popping up all over the place.

You aren't gonna lock the converter at WOT are you?
 

2bscrewed

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I hope the trans works out. Many reports of failures are popping up all over the place.

You aren't gonna lock the converter at WOT are you?

Failures of 4R70W's in general, or BC Automotives 4R70W's are failing? I was gonna lock it up WOT, as I'm supposed to be able to, or else I wouldn't have bought such an expensive triple disc converter.
 

Blackedout

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Congrats on the swap... I'm just finishing up mine went with FB... trying to figure out what to do with my back up lites also... can't wait to drive it...
 

2bscrewed

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Why are you waiting till FALL to take it to the track?
Would like to see what this enjoying your car thing is all about! haha I've been working on this thing for pretty much 2 years straight. Every time I've broken it in the past was at the track, so I'm gonna hold off a few months.
 

2bscrewed

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Congrats on the swap... I'm just finishing up mine went with FB... trying to figure out what to do with my back up lites also... can't wait to drive it...
Cool, Darrin uses FB's valve bodies.

Should put up some great times at the track now!
I hope so,I don't know how it can't, even leaving soft it should be much quicker without going in and out of boost on every shift.
incar video? Looks awesome!!
I'll def have video once I'm ready to beat on it.
 

steeltoe

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Looks good Shane.

That dyno wouldn't happen to be Street's old dyno? I know when Ed Hutchins had it. The AFR sensor would go out on it mid pull.
 
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2bscrewed

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Looks good Shane.

That dyno wouldn't happen to be Street's old dyno? I know when Ed Hutchins had it. The AFR sensor would go out on it mid pull.
No, it didn't come from street, and the AFR is usually right on, so we need to do some more testing. It just got ridiculously hot here, so I'm not doing anything til it cools off a bit.
 

2bscrewed

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how much was everything???

If my T56 craps out again im going with a 4r70w
Transmission (without T brake) was about $4k and that came with the converter and cooler.
Drive shaft set up was $470
Misc swap parts were about $150-$200
Shifter was $240
Fluid was $150
Cooler lines/fittings were about $150
So you are looking at about $5500-$6000 for everything depending on what you get.
 

TRBO VNM

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looking good Shane, but thought you have had this done for a while now. just now posting the thread?
 

2bscrewed

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Looks good! :beer:
Thanks, I'll have to hit you up if I ever get to bring my car home on one of my visits with my family up there.

looking good Shane, but thought you have had this done for a while now. just now posting the thread?
It's been running for a couple weeks, just got the lock up fixed last Friday though. Didn't want to post the thread til that was straight.
 

Blackedout

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FYI go to the Hurst web site they have a back up switch for their shifters...Just ordered mine.. $25.?? + shipping
 

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