[QUOTE=Huitt24;3392142]So am I the other member over the 400 mark? and I put out just a hair more than Matt... LoL hey Matt crank it up man!
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Haha when I get to the dyno again it will be more I need to get the AIT's in the 50's I think it will make 430 in a few weeks I'll post up my new dyno graph

 

Oops, I forgot about you. Sorry about that. The one I was thinking of only put down 406 (I think) don't remember who it was.

So I was incorrect, there are at least 3 who have cracked 400 with a roush.

 

I disagree. The rating it at the input shaft. The torque multiplication of 1st gear in the 4R70w is 2.84:1. The converter on the 5.4 multiplies torque at a ratio of 1.9:1. So if you are using only 250 ft-lbs of torque x 1.9 x 2.84 you are putting 1354 ft-lbs of torque through the output shaft on a stock 4R70W Why is the 4R70W numbered with a 70? The rating is at the input shaft. So the intent of my post was to clear up the misinformation that the 4R75 was rated at 375. Yes, if you are putting 400+ to the wheels you have exceeded the rating of the 4R75 when the conditions are right. And that is why I recommend talking with your tuner........

Regards

Jean Marc Chartier

 

Actually, you're saying the same thing I said with more detail. I agree that its not "rated" at 375, but its not going to handle 750 once it gets to the drive-shaft. That's the point of my post. It's really not a well suited transmission for late model F150s.

 

how come im not the other member lol i know mine is over the 400hp mark. im close to that number with the 22's on the truck now but can pass right by that with the stock wheels and i have no transmission issues. maybe when MT does another dyno day you might see quite a few Roush over 400 with no trans issues. it all depends on how you take care of it. my buddy just got his truck back together with the blown motor. 2 weeks ago he blew the trans and you talk about hard on it. never let it warm up. constantly shifting the gears doing burnouts. some pretty ones at that. now its slipping from 1st to 2nd and doesnt want to lock up in overdrive lol. hes putting in one from dirtydog and i cant wait to see what his makes on 15lbs of boost.