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Thread: 4R75E high speed durability questions

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    I shall not pass this way again. Smokestacklightnin's Avatar
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    Default 4R75E high speed durability questions

    Wanting opinions and facts about the 4R75E in my 2011. From my research I know it is stronger than the 4r70w. Are they prone to tail shaft bearing failure or other issues due to high speed? Is this transmission identical to those used in police application? Thinking about getting a tuner and raising the speed governor to 125 or 130. Thinking about maybe in the future to participate in the Texas Mile 😁. Any drive shaft concerns? My tires are T rated so I know higher will be needed. Thanks for all info info and ideas.

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    I shall not pass this way again. Smokestacklightnin's Avatar
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    After some research the transmission for police is not much different than civilian. The tail shaft housing is longer due a longer input shaft. The drive shaft is aluminum and shorter than the steel civilian shaft. The steel driveshaft is good to 110 mph sustained. The aluminum is good to 150. The police driveshaft can be used by using the civilian yokes with a fabtech spacer to compensate for the shorter drive shaft. The civilian yokes are stronger than the police. This is easier labor than swapping all the police specific components.

  3. #3
    I shall not pass this way again. Smokestacklightnin's Avatar
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    atdr.net has a very good explanation on the driveshaft swap.

    2011 Grand Marquis LS Ultimate Edition
    1984 2Dr Crown Vic "The Millennium Falcon" RIP
    Carbed 5.0 HO w/nitrous , Performer RPM intake, GT40P heads, E303 cam, FRP Shorties, FRP 9mm plug wires, Off-Road H-pipe, Magnaflow round mufflers, 2000 rpm stall
    NA-15.78@91.21, 80hp shot-14.48@96.21

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    Beater gonna beat sly's Avatar
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    I can say for a fact that my 93 LX with it's rebalanced steel shaft, solid slip yoke, and 3.55L gears are stable for sustained 100mph runs while fully loaded with the cargo box hanging off the hitch. Followed a Charger for about 2 hours at that speed headed down to Houston one Christmas.

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    Yeah my 04 had no problems with quite a few early morning high speed runs over its life.
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    I shall not pass this way again. Smokestacklightnin's Avatar
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    Quote Originally Posted by tjc78 View Post
    Yeah my 04 had no problems with quite a few early morning high speed runs over its life.
    About how high? Main concern is safety. Don't want to chunk a drive shaft at speed. If I can get away with stock I'll use a drive shaft loop with it. Would be running a standing Mile, so not a constant speed.

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    If you're going with 2.73 gears... You'll have no worries I'd imagine. I've had my 93 up to 110 with zero issues. That was almost 5000 rpm driveshaft. With 2.73 gears, that would be about 3800 RPM. So with 2.73, you'll be good up to 145mph at least. I can't imagine a panther getting much that in a standing mile without much mods. Also, unless the PCM has been tuned, it'll be limited to 110 mph or so for a civilian PCM or 140 for CVPI IIRC (CVPI may not be limited). Besides... you'll know well before the driveshaft gives up. The vibrations will be pronounced.

    I do suggest having the driveshaft balanced though.
    Last edited by sly; 03-10-2019 at 12:46 PM.

    Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. -- Albert Einstein
    rides: 88 MGM (SOLD), 93 Vic, 2000 Crown Vic, 2003 Expedition
    Quote Originally Posted by gadget73
    ... and it should all work like magic and unicorns and stuff.
    Quote Originally Posted by dmccaig
    Overhead, some poor bastards are flying in airplanes.

  8. #8
    I shall not pass this way again. Smokestacklightnin's Avatar
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    I'll be sticking with 2.73. Like you said Sly, and based on further research, the stock driveshaft should be okay just above 5500 rpm. Looking at a hypertech tuner to raise the speed governor and a 93 octane tune. Plan to get driveshaft balanced, replace u joints, and add driveshaft loop. With everything else stock would be happy to see 125+ mph. But if not would still be fun to try, and mark something off the bucket list.

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    Quote Originally Posted by Smokestacklightnin View Post
    About how high? Main concern is safety. Don't want to chunk a drive shaft at speed. If I can get away with stock I'll use a drive shaft loop with it. Would be running a standing Mile, so not a constant speed.
    Up to the limiter with 2.73s out back.
    2017 Buick Enclave 3.6 (Burgundy/Beige)
    2017 Hyundai Elantra SE w/tech (Silver/Grey)
    Past Panthers
    1989 Grand Marquis LS (Cabernet/Grey), 1989 Lincoln Town Car SS (White/Blue), 2004 Mercury Grand Marquis Ultimate (White/Black)

    Quote Originally Posted by Lincolnmania View Post
    if its got tits or tires it's bound to give you trouble

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